Redefine the meaning of sample counts in GPU backend.

Old: 0 -> nonMSAA 1+ -> MSAA New: 0 -> error/unsupported 1 -> nonMSAA 2+ -> MSAA We still allow 0 to mean nonMSAA in three sets of public APIs for backwards compatibility: 1) SkSurface factories 2) GrBackendRenderTarget constructors 3) GrCaps::getSampleCnt()'s requestedCount parameter However, we immediately clamp to 1 and treat 0 as invalid/non-renderable internally. This also changes the behavior when using a large sample count. We now fail in that case rather than using the largest sample available sample count. GrCaps::getSampleCount() will return 0 in this case. Bug: skia: Change-Id: Ida22c6b22c1365e563c9046b611e88bf5eb3ff33 Reviewed-on: https://skia-review.googlesource.com/101560 Reviewed-by: Greg Daniel <egdaniel@google.com> Commit-Queue: Brian Salomon <bsalomon@google.com>
author: Brian Salomon <bsalomon@google.com> 2018-02-01 12:54:30 -0500
committer: Skia Commit-Bot <skia-commit-bot@chromium.org> 2018-02-01 18:16:58 +0000
commit: 48825b11ad25c98b9a4884d5cc0edd4e290c4409 (patch)
tree: 4278b01107ad8da03453c879ee50ce1a471d2ee2
parent: f8393c861975350c4ca9d4f6c95b186c081dbbcf (diff)
86 files changed, 366 insertions, 266 deletions
diff --git a/debugger/QT/SkGLWidget.cpp b/debugger/QT/SkGLWidget.cpp
index baee2bbdac..44a15dca38 100644
--- a/debugger/QT/SkGLWidget.cpp
+++ b/debugger/QT/SkGLWidget.cpp
@@ -20,7 +20,7 @@ SkGLWidget::~SkGLWidget() {
 
 void SkGLWidget::setSampleCount(int sampleCount) {
     QGLFormat currentFormat = format();
-    currentFormat.setSampleBuffers(sampleCount > 0);
+    currentFormat.setSampleBuffers(sampleCount > 1);
     currentFormat.setSamples(sampleCount);
     setFormat(currentFormat);
 }
@@ -89,6 +89,7 @@ GrBackendRenderTarget SkGLWidget::getBackendRenderTarget() {
     int sampleCnt;
     GR_GL_GetIntegerv(fCurIntf.get(), GR_GL_FRAMEBUFFER_BINDING, &info.fFBOID);
     GR_GL_GetIntegerv(fCurIntf.get(), GR_GL_SAMPLES, &sampleCnt);
+    sampleCnt = SkTMax(sampleCnt, 1);
     GR_GL_GetIntegerv(fCurIntf.get(), GR_GL_STENCIL_BITS, &stencilBits);
     // We are on desktop so we assume the internal config is RGBA
     info.fFormat = GR_GL_RGBA8;
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index db1e064d72..157a484d2b 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -350,7 +350,7 @@ public:
     bool serial() const override { return !fThreaded; }
     const char* fileExtension() const override { return "png"; }
     SinkFlags flags() const override {
-        SinkFlags::Multisampled ms = fSampleCount > 0 ? SinkFlags::kMultisampled
+        SinkFlags::Multisampled ms = fSampleCount > 1 ? SinkFlags::kMultisampled
                                                       : SinkFlags::kNotMultisampled;
         return SinkFlags{ SinkFlags::kGPU, SinkFlags::kDirect, ms };
     }
diff --git a/example/HelloWorld.cpp b/example/HelloWorld.cpp
index 5954e71532..b20d30a780 100644
--- a/example/HelloWorld.cpp
+++ b/example/HelloWorld.cpp
@@ -38,7 +38,7 @@ HelloWorld::~HelloWorld() {
 }
 
 void HelloWorld::updateTitle() {
-    if (!fWindow || fWindow->sampleCount() < 0) {
+    if (!fWindow || fWindow->sampleCount() <= 1) {
         return;
     }
 
diff --git a/include/core/SkSurface.h b/include/core/SkSurface.h
index 1f2c4b7f07..d621fdf062 100644
--- a/include/core/SkSurface.h
+++ b/include/core/SkSurface.h
@@ -90,7 +90,7 @@ public:
     /**
      *  Used to wrap a pre-existing backend 3D API texture as a SkSurface. Skia will not assume
      *  ownership of the texture and the client must ensure the texture is valid for the lifetime
-     *  of the SkSurface. If sampleCnt > 0, then we will create an intermediate mssa surface which
+     *  of the SkSurface. If sampleCnt > 1, then we will create an intermediate mssa surface which
      *  we will use for rendering. We then resolve into the passed in texture.
      */
     static sk_sp<SkSurface> MakeFromBackendTexture(GrContext* context,
@@ -102,13 +102,13 @@ public:
     /**
      *  Used to wrap a pre-existing backend 3D API texture as a SkSurface. Skia will not assume
      *  ownership of the texture and the client must ensure the texture is valid for the lifetime
-     *  of the SkSurface. If sampleCnt > 0, then we will create an intermediate mssa surface which
+     *  of the SkSurface. If sampleCnt > 1, then we will create an intermediate mssa surface which
      *  we will use for rendering. We then resolve into the passed in texture.
      *
      *  The GrBackendTexture must have a valid backend format supplied (GrGLTextureInfo::fFormat,
      *  GrVkImageInfo::fFormat, etc.) in it. The passed in SkColorType informs skia how it should
      *  interpret the backend format supplied by the GrBackendTexture. If the format in the
-     *  GrBackendTexture is not compitable with the sampleCnt, SkColorType, and SkColorSpace we
+     *  GrBackendTexture is not compatible with the sampleCnt, SkColorType, and SkColorSpace we
      *  will return nullptr.
      */
     static sk_sp<SkSurface> MakeFromBackendTexture(GrContext* context,
@@ -128,7 +128,7 @@ public:
      *  The GrBackendRenderTarget must have a valid backend format set (GrGLTextureInfo::fFormat,
      *  GrVkImageInfo::fFormat, etc.) in it. The passed in SkColorType informs skia how it should
      *  interpret the backend format supplied by the GrBackendRenderTarget. If the format in the
-     *  GrBackendRenderTarget is not compitable with the sampleCnt, SkColorType, and SkColorSpace
+     *  GrBackendRenderTarget is not compatible with the sampleCnt, SkColorType, and SkColorSpace
      *  we will return nullptr.
      */
     static sk_sp<SkSurface> MakeFromBackendRenderTarget(GrContext* context,
@@ -162,7 +162,7 @@ public:
      *  The GrBackendTexture must have a valid backend format supplied (GrGLTextureInfo::fFormat,
      *  GrVkImageInfo::fFormat, etc.) in it. The passed in SkColorType informs skia how it should
      *  interpret the backend format supplied by the GrBackendTexture. If the format in the
-     *  GrBackendTexture is not compitable with the sampleCnt, SkColorType, and SkColorSpace we
+     *  GrBackendTexture is not compatible with the sampleCnt, SkColorType, and SkColorSpace we
      *  will return nullptr.
      */
     static sk_sp<SkSurface> MakeFromBackendTextureAsRenderTarget(GrContext* context,
diff --git a/include/gpu/GrCaps.h b/include/gpu/GrCaps.h
index f4d6e06280..ab77c8877f 100644
--- a/include/gpu/GrCaps.h
+++ b/include/gpu/GrCaps.h
@@ -135,7 +135,9 @@ public:
     int maxRasterSamples() const { return fMaxRasterSamples; }
 
     // Find a sample count greater than or equal to the requested count which is supported for a
-    // color buffer of the given config. If MSAA is not support for the config we will return 0.
+    // color buffer of the given config or 0 if no such sample count is supported. If the requested
+    // sample count is 1 then 1 will be returned if non-MSAA rendering is supported, otherwise 0.
+    // For historical reasons requestedCount==0 is handled identically to requestedCount==1.
     virtual int getSampleCount(int requestedCount, GrPixelConfig config) const = 0;
 
     int maxWindowRectangles() const { return fMaxWindowRectangles; }
diff --git a/include/gpu/GrContext.h b/include/gpu/GrContext.h
index f85efc4940..3c79ac74ce 100644
--- a/include/gpu/GrContext.h
+++ b/include/gpu/GrContext.h
@@ -226,7 +226,7 @@ public:
                                                  int width, int height,
                                                  GrPixelConfig config,
                                                  sk_sp<SkColorSpace> colorSpace,
-                                                 int sampleCnt = 0,
+                                                 int sampleCnt = 1,
                                                  GrMipMapped = GrMipMapped::kNo,
                                                  GrSurfaceOrigin origin = kBottomLeft_GrSurfaceOrigin,
                                                  const SkSurfaceProps* surfaceProps = nullptr,
@@ -242,7 +242,7 @@ public:
                                                  int width, int height,
                                                  GrPixelConfig config,
                                                  sk_sp<SkColorSpace> colorSpace,
-                                                 int sampleCnt = 0,
+                                                 int sampleCnt = 1,
                                                  GrMipMapped = GrMipMapped::kNo,
                                                  GrSurfaceOrigin origin = kBottomLeft_GrSurfaceOrigin,
                                                  const SkSurfaceProps* surfaceProps = nullptr,
diff --git a/include/gpu/GrRenderTarget.h b/include/gpu/GrRenderTarget.h
index 4eee7f63ce..9be6e1d8d0 100644
--- a/include/gpu/GrRenderTarget.h
+++ b/include/gpu/GrRenderTarget.h
@@ -33,10 +33,11 @@ public:
     const GrRenderTarget* asRenderTarget() const  override { return this; }
 
     // GrRenderTarget
-    bool isStencilBufferMultisampled() const { return fSampleCnt > 0; }
+    bool isStencilBufferMultisampled() const { return fSampleCnt > 1; }
 
     GrFSAAType fsaaType() const {
-        if (!fSampleCnt) {
+        SkASSERT(fSampleCnt >= 1);
+        if (fSampleCnt <= 1) {
             SkASSERT(!(fFlags & GrRenderTargetFlags::kMixedSampled));
             return GrFSAAType::kNone;
         }
@@ -53,7 +54,7 @@ public:
      * Returns the number of samples/pixel in the color buffer (Zero if non-MSAA or mixed sampled).
      */
     int numColorSamples() const {
-        return GrFSAAType::kMixedSamples == this->fsaaType() ? 0 : fSampleCnt;
+        return GrFSAAType::kMixedSamples == this->fsaaType() ? 1 : fSampleCnt;
     }
 
     /**
diff --git a/include/gpu/GrTypes.h b/include/gpu/GrTypes.h
index 3081543aac..ab21fba732 100644
--- a/include/gpu/GrTypes.h
+++ b/include/gpu/GrTypes.h
@@ -402,13 +402,12 @@ struct GrMipLevel {
  */
 struct GrSurfaceDesc {
     GrSurfaceDesc()
-        : fFlags(kNone_GrSurfaceFlags)
-        , fOrigin(kTopLeft_GrSurfaceOrigin)
-        , fWidth(0)
-        , fHeight(0)
-        , fConfig(kUnknown_GrPixelConfig)
-        , fSampleCnt(0) {
-    }
+            : fFlags(kNone_GrSurfaceFlags)
+            , fOrigin(kTopLeft_GrSurfaceOrigin)
+            , fWidth(0)
+            , fHeight(0)
+            , fConfig(kUnknown_GrPixelConfig)
+            , fSampleCnt(1) {}
 
     GrSurfaceFlags         fFlags;  //!< bitfield of TextureFlags
     GrSurfaceOrigin        fOrigin; //!< origin of the texture
@@ -422,11 +421,11 @@ struct GrSurfaceDesc {
     GrPixelConfig          fConfig;
 
     /**
-     * The number of samples per pixel or 0 to disable full scene AA. This only
+     * The number of samples per pixel. Zero is treated equivalently to 1. This only
      * applies if the kRenderTarget_GrSurfaceFlag is set. The actual number
      * of samples may not exactly match the request. The request will be rounded
-     * up to the next supported sample count, or down if it is larger than the
-     * max supported count.
+     * up to the next supported sample count. A value larger than the largest
+     * supported sample count will fail.
      */
     int                    fSampleCnt;
 };
diff --git a/include/private/GrRenderTargetProxy.h b/include/private/GrRenderTargetProxy.h
index 1cd3d5d1a2..1d5d8042ce 100644
--- a/include/private/GrRenderTargetProxy.h
+++ b/include/private/GrRenderTargetProxy.h
@@ -26,7 +26,7 @@ public:
     bool instantiate(GrResourceProvider*) override;
 
     GrFSAAType fsaaType() const {
-        if (!fSampleCnt) {
+        if (fSampleCnt <= 1) {
             SkASSERT(!(fRenderTargetFlags & GrRenderTargetFlags::kMixedSampled));
             return GrFSAAType::kNone;
         }
@@ -50,7 +50,7 @@ public:
      * Returns the number of samples/pixel in the color buffer (Zero if non-MSAA or mixed sampled).
      */
     int numColorSamples() const {
-        return GrFSAAType::kMixedSamples == this->fsaaType() ? 0 : fSampleCnt;
+        return GrFSAAType::kMixedSamples == this->fsaaType() ? 1 : fSampleCnt;
     }
 
     int maxWindowRectangles(const GrCaps& caps) const;
diff --git a/src/gpu/GrBackendSurface.cpp b/src/gpu/GrBackendSurface.cpp
index 406cb228ea..16fa793d25 100644
--- a/src/gpu/GrBackendSurface.cpp
+++ b/src/gpu/GrBackendSurface.cpp
@@ -106,7 +106,7 @@ GrBackendRenderTarget::GrBackendRenderTarget(int width,
                                              const GrVkImageInfo& vkInfo)
         : fWidth(width)
         , fHeight(height)
-        , fSampleCnt(sampleCnt)
+        , fSampleCnt(SkTMax(1, sampleCnt))
         , fStencilBits(stencilBits)
         , fConfig(GrVkFormatToPixelConfig(vkInfo.fFormat))
         , fBackend(kVulkan_GrBackend)
@@ -121,7 +121,7 @@ GrBackendRenderTarget::GrBackendRenderTarget(int width,
                                              const GrGLFramebufferInfo& glInfo)
         : fWidth(width)
         , fHeight(height)
-        , fSampleCnt(sampleCnt)
+        , fSampleCnt(SkTMax(1, sampleCnt))
         , fStencilBits(stencilBits)
         , fConfig(config)
         , fBackend(kOpenGL_GrBackend)
@@ -134,7 +134,7 @@ GrBackendRenderTarget::GrBackendRenderTarget(int width,
                                              const GrGLFramebufferInfo& glInfo)
         : fWidth(width)
         , fHeight(height)
-        , fSampleCnt(sampleCnt)
+        , fSampleCnt(SkTMax(1, sampleCnt))
         , fStencilBits(stencilBits)
         , fConfig(GrGLSizedFormatToPixelConfig(glInfo.fFormat))
         , fBackend(kOpenGL_GrBackend)
diff --git a/src/gpu/GrBackendTextureImageGenerator.cpp b/src/gpu/GrBackendTextureImageGenerator.cpp
index ae27912b32..af28409cfe 100644
--- a/src/gpu/GrBackendTextureImageGenerator.cpp
+++ b/src/gpu/GrBackendTextureImageGenerator.cpp
@@ -186,8 +186,8 @@ sk_sp<GrTextureProxy> GrBackendTextureImageGenerator::onGenerateTexture(
         GrMipMapped mipMapped = willNeedMipMaps ? GrMipMapped::kYes : GrMipMapped::kNo;
 
         sk_sp<GrRenderTargetContext> rtContext(context->makeDeferredRenderTargetContext(
-                SkBackingFit::kExact, info.width(), info.height(), proxy->config(), nullptr,
-                0, mipMapped, proxy->origin(), nullptr, SkBudgeted::kYes));
+                SkBackingFit::kExact, info.width(), info.height(), proxy->config(), nullptr, 1,
+                mipMapped, proxy->origin(), nullptr, SkBudgeted::kYes));
 
         if (!rtContext) {
             return nullptr;
diff --git a/src/gpu/GrBlurUtils.cpp b/src/gpu/GrBlurUtils.cpp
index b79a38a884..b6e3092d5a 100644
--- a/src/gpu/GrBlurUtils.cpp
+++ b/src/gpu/GrBlurUtils.cpp
@@ -110,7 +110,7 @@ static sk_sp<GrTextureProxy> create_mask_GPU(GrContext* context,
                                              int sampleCnt) {
     if (GrAA::kNo == aa) {
         // Don't need MSAA if mask isn't AA
-        sampleCnt = 0;
+        sampleCnt = 1;
     }
 
     sk_sp<GrRenderTargetContext> rtContext(context->makeDeferredRenderTargetContextWithFallback(
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index b427e70beb..baa5232032 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -862,6 +862,7 @@ sk_sp<GrRenderTargetContext> GrContextPriv::makeBackendTextureRenderTargetContex
                                                                    sk_sp<SkColorSpace> colorSpace,
                                                                    const SkSurfaceProps* props) {
     ASSERT_SINGLE_OWNER_PRIV
+    SkASSERT(sampleCnt > 0);
 
     sk_sp<GrTextureProxy> proxy(this->proxyProvider()->createWrappedTextureProxy(tex, origin,
                                                                                  sampleCnt));
@@ -898,7 +899,7 @@ sk_sp<GrRenderTargetContext> GrContextPriv::makeBackendTextureAsRenderTargetRend
                                                      sk_sp<SkColorSpace> colorSpace,
                                                      const SkSurfaceProps* props) {
     ASSERT_SINGLE_OWNER_PRIV
-
+    SkASSERT(sampleCnt > 0);
     sk_sp<GrSurfaceProxy> proxy(this->proxyProvider()->createWrappedRenderTargetProxy(tex, origin,
                                                                                       sampleCnt));
     if (!proxy) {
@@ -949,7 +950,8 @@ sk_sp<GrRenderTargetContext> GrContext::makeDeferredRenderTargetContextWithFallb
                                                                  GrSurfaceOrigin origin,
                                                                  const SkSurfaceProps* surfaceProps,
                                                                  SkBudgeted budgeted) {
-    if (!this->caps()->isConfigRenderable(config, sampleCnt > 0)) {
+    SkASSERT(sampleCnt > 0);
+    if (!this->caps()->isConfigRenderable(config, sampleCnt > 1)) {
         config = GrPixelConfigFallback(config);
     }
 
@@ -968,6 +970,7 @@ sk_sp<GrRenderTargetContext> GrContext::makeDeferredRenderTargetContext(
                                                         GrSurfaceOrigin origin,
                                                         const SkSurfaceProps* surfaceProps,
                                                         SkBudgeted budgeted) {
+    SkASSERT(sampleCnt > 0);
     if (this->abandoned()) {
         return nullptr;
     }
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index eb005d110a..bea6a601e6 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -94,12 +94,16 @@ static bool check_texture_creation_params(const GrCaps& caps, const GrSurfaceDes
     }
 
     *isRT = SkToBool(desc.fFlags & kRenderTarget_GrSurfaceFlag);
-    if (*isRT && !caps.isConfigRenderable(desc.fConfig, desc.fSampleCnt > 0)) {
+    if (*isRT && !caps.isConfigRenderable(desc.fConfig, desc.fSampleCnt > 1)) {
+        return false;
+    }
+
+    if (desc.fSampleCnt < 1) {
         return false;
     }
 
     // We currently do not support multisampled textures
-    if (!*isRT && desc.fSampleCnt > 0) {
+    if (!*isRT && desc.fSampleCnt > 1) {
         return false;
     }
 
@@ -131,9 +135,14 @@ sk_sp<GrTexture> GrGpu::createTexture(const GrSurfaceDesc& origDesc, SkBudgeted
         return nullptr;
     }
 
-    desc.fSampleCnt = caps->getSampleCount(desc.fSampleCnt, desc.fConfig);
+    if (isRT) {
+        desc.fSampleCnt = caps->getSampleCount(desc.fSampleCnt, desc.fConfig);
+        if (!desc.fSampleCnt) {
+            return nullptr;
+        }
+    }
     // Attempt to catch un- or wrongly initialized sample counts.
-    SkASSERT(desc.fSampleCnt >= 0 && desc.fSampleCnt <= 64);
+    SkASSERT(desc.fSampleCnt > 0 && desc.fSampleCnt <= 64);
 
     if (mipLevelCount && (desc.fFlags & kPerformInitialClear_GrSurfaceFlag)) {
         return nullptr;
@@ -179,8 +188,11 @@ sk_sp<GrTexture> GrGpu::wrapBackendTexture(const GrBackendTexture& backendTex,
 sk_sp<GrTexture> GrGpu::wrapRenderableBackendTexture(const GrBackendTexture& backendTex,
                                                      int sampleCnt, GrWrapOwnership ownership) {
     this->handleDirtyContext();
+    if (sampleCnt < 1) {
+        return nullptr;
+    }
     if (!this->caps()->isConfigTexturable(backendTex.config()) ||
-        !this->caps()->isConfigRenderable(backendTex.config(), sampleCnt > 0)) {
+        !this->caps()->isConfigRenderable(backendTex.config(), sampleCnt > 1)) {
         return nullptr;
     }
 
@@ -197,7 +209,7 @@ sk_sp<GrTexture> GrGpu::wrapRenderableBackendTexture(const GrBackendTexture& bac
 }
 
 sk_sp<GrRenderTarget> GrGpu::wrapBackendRenderTarget(const GrBackendRenderTarget& backendRT) {
-    if (!this->caps()->isConfigRenderable(backendRT.config(), backendRT.sampleCnt() > 0)) {
+    if (!this->caps()->isConfigRenderable(backendRT.config(), backendRT.sampleCnt() > 1)) {
         return nullptr;
     }
     this->handleDirtyContext();
@@ -207,7 +219,7 @@ sk_sp<GrRenderTarget> GrGpu::wrapBackendRenderTarget(const GrBackendRenderTarget
 sk_sp<GrRenderTarget> GrGpu::wrapBackendTextureAsRenderTarget(const GrBackendTexture& tex,
                                                               int sampleCnt) {
     this->handleDirtyContext();
-    if (!this->caps()->isConfigRenderable(tex.config(), sampleCnt > 0)) {
+    if (!this->caps()->isConfigRenderable(tex.config(), sampleCnt > 1)) {
         return nullptr;
     }
     int maxSize = this->caps()->maxTextureSize();
diff --git a/src/gpu/GrProxyProvider.cpp b/src/gpu/GrProxyProvider.cpp
index ec05243d18..193b321190 100644
--- a/src/gpu/GrProxyProvider.cpp
+++ b/src/gpu/GrProxyProvider.cpp
@@ -322,12 +322,16 @@ sk_sp<GrTextureProxy> GrProxyProvider::createProxy(const GrSurfaceDesc& desc,
     }
 
     bool willBeRT = SkToBool(desc.fFlags & kRenderTarget_GrSurfaceFlag);
-    if (willBeRT && !caps->isConfigRenderable(desc.fConfig, desc.fSampleCnt > 0)) {
+    if (willBeRT && !caps->isConfigRenderable(desc.fConfig, desc.fSampleCnt > 1)) {
         return nullptr;
     }
 
     // We currently do not support multisampled textures
-    if (!willBeRT && desc.fSampleCnt > 0) {
+    if (!willBeRT && desc.fSampleCnt > 1) {
+        return nullptr;
+    }
+
+    if (willBeRT && !caps->getSampleCount(desc.fSampleCnt, desc.fConfig)) {
         return nullptr;
     }
 
@@ -505,7 +509,7 @@ sk_sp<GrTextureProxy> GrProxyProvider::createFullyLazyProxy(LazyInstantiateCallb
     desc.fWidth = -1;
     desc.fHeight = -1;
     desc.fConfig = config;
-    desc.fSampleCnt = 0;
+    desc.fSampleCnt = 1;
 
     return this->createLazyProxy(std::move(callback), desc, GrMipMapped::kNo,
                                  SkBackingFit::kApprox, SkBudgeted::kYes);
diff --git a/src/gpu/GrRenderTarget.cpp b/src/gpu/GrRenderTarget.cpp
index 3090219751..36fa4ddf1b 100644
--- a/src/gpu/GrRenderTarget.cpp
+++ b/src/gpu/GrRenderTarget.cpp
@@ -27,7 +27,7 @@ GrRenderTarget::GrRenderTarget(GrGpu* gpu, const GrSurfaceDesc& desc,
         , fMultisampleSpecsID(0)
         , fFlags(flags) {
     SkASSERT(desc.fFlags & kRenderTarget_GrSurfaceFlag);
-    SkASSERT(!(fFlags & GrRenderTargetFlags::kMixedSampled) || fSampleCnt > 0);
+    SkASSERT(!(fFlags & GrRenderTargetFlags::kMixedSampled) || fSampleCnt > 1);
     SkASSERT(!(fFlags & GrRenderTargetFlags::kWindowRectsSupport) ||
              gpu->caps()->maxWindowRectangles() > 0);
     fResolveRect = SkRectPriv::MakeILargestInverted();
diff --git a/src/gpu/GrRenderTargetProxy.cpp b/src/gpu/GrRenderTargetProxy.cpp
index 9eb37a0b2f..841d4b18fd 100644
--- a/src/gpu/GrRenderTargetProxy.cpp
+++ b/src/gpu/GrRenderTargetProxy.cpp
@@ -26,7 +26,7 @@ GrRenderTargetProxy::GrRenderTargetProxy(const GrCaps& caps, const GrSurfaceDesc
         , fRenderTargetFlags(GrRenderTargetFlags::kNone) {
     // Since we know the newly created render target will be internal, we are able to precompute
     // what the flags will ultimately end up being.
-    if (caps.usesMixedSamples() && fSampleCnt > 0) {
+    if (caps.usesMixedSamples() && fSampleCnt > 1) {
         fRenderTargetFlags |= GrRenderTargetFlags::kMixedSampled;
     }
     if (caps.maxWindowRectangles() > 0) {
@@ -97,7 +97,11 @@ sk_sp<GrSurface> GrRenderTargetProxy::createSurface(GrResourceProvider* resource
 }
 
 size_t GrRenderTargetProxy::onUninstantiatedGpuMemorySize() const {
-    int colorSamplesPerPixel = this->numColorSamples() + 1;
+    int colorSamplesPerPixel = this->numColorSamples();
+    if (colorSamplesPerPixel > 1) {
+        // Add one for the resolve buffer.
+        ++colorSamplesPerPixel;
+    }
 
     // TODO: do we have enough information to improve this worst case estimate?
     return GrSurface::ComputeSize(this->config(), this->width(), this->height(),
diff --git a/src/gpu/GrResourceProvider.cpp b/src/gpu/GrResourceProvider.cpp
index 9cf4e6c3e7..011ad6f5a9 100644
--- a/src/gpu/GrResourceProvider.cpp
+++ b/src/gpu/GrResourceProvider.cpp
@@ -47,6 +47,10 @@ GrResourceProvider::GrResourceProvider(GrGpu* gpu, GrResourceCache* cache, GrSin
 }
 
 bool validate_desc(const GrSurfaceDesc& desc, const GrCaps& caps, int levelCount = 0) {
+    if (desc.fSampleCnt < 1) {
+        return false;
+    }
+
     if (desc.fWidth <= 0 || desc.fHeight <= 0) {
         return false;
     }
@@ -54,11 +58,11 @@ bool validate_desc(const GrSurfaceDesc& desc, const GrCaps& caps, int levelCount
         return false;
     }
     if (desc.fFlags & kRenderTarget_GrSurfaceFlag) {
-        if (!caps.isConfigRenderable(desc.fConfig, desc.fSampleCnt > 0)) {
+        if (!caps.isConfigRenderable(desc.fConfig, desc.fSampleCnt > 1)) {
             return false;
         }
     } else {
-        if (desc.fSampleCnt) {
+        if (desc.fSampleCnt > 1) {
             return false;
         }
     }
@@ -156,7 +160,6 @@ sk_sp<GrTexture> GrResourceProvider::createTexture(const GrSurfaceDesc& desc,
 sk_sp<GrTexture> GrResourceProvider::createTexture(const GrSurfaceDesc& desc, SkBudgeted budgeted,
                                                    uint32_t flags) {
     ASSERT_SINGLE_OWNER
-
     if (this->isAbandoned()) {
         return nullptr;
     }
diff --git a/src/gpu/GrResourceProvider.h b/src/gpu/GrResourceProvider.h
index bf7f28e93d..18df8597bd 100644
--- a/src/gpu/GrResourceProvider.h
+++ b/src/gpu/GrResourceProvider.h
@@ -88,7 +88,7 @@ public:
                                         GrWrapOwnership = kBorrow_GrWrapOwnership);
 
     /**
-     * This makes the backend texture be renderable. If sampleCnt is > 0 and the underlying API
+     * This makes the backend texture be renderable. If sampleCnt is > 1 and the underlying API
      * uses separate MSAA render buffers then a MSAA render buffer is created that resolves
      * to the texture.
      */
diff --git a/src/gpu/GrSurface.cpp b/src/gpu/GrSurface.cpp
index ec503d7066..b35683c548 100644
--- a/src/gpu/GrSurface.cpp
+++ b/src/gpu/GrSurface.cpp
@@ -29,8 +29,9 @@ size_t GrSurface::WorstCaseSize(const GrSurfaceDesc& desc, bool useNextPow2) {
     bool isRenderTarget = SkToBool(desc.fFlags & kRenderTarget_GrSurfaceFlag);
     if (isRenderTarget) {
         // We own one color value for each MSAA sample.
-        int colorValuesPerPixel = SkTMax(1, desc.fSampleCnt);
-        if (desc.fSampleCnt) {
+        SkASSERT(desc.fSampleCnt >= 1);
+        int colorValuesPerPixel = desc.fSampleCnt;
+        if (desc.fSampleCnt > 1) {
             // Worse case, we own the resolve buffer so that is one more sample per pixel.
             colorValuesPerPixel += 1;
         }
diff --git a/src/gpu/GrSurfaceProxy.cpp b/src/gpu/GrSurfaceProxy.cpp
index 64c47b56b1..4020758259 100644
--- a/src/gpu/GrSurfaceProxy.cpp
+++ b/src/gpu/GrSurfaceProxy.cpp
@@ -26,7 +26,7 @@ static bool is_valid_fully_lazy(const GrSurfaceDesc& desc, SkBackingFit fit) {
     return desc.fWidth <= 0 &&
            desc.fHeight <= 0 &&
            desc.fConfig != kUnknown_GrPixelConfig &&
-           desc.fSampleCnt == 0 &&
+           desc.fSampleCnt == 1 &&
            SkBackingFit::kApprox == fit;
 }
 
@@ -190,7 +190,7 @@ bool GrSurfaceProxy::instantiateImpl(GrResourceProvider* resourceProvider, int s
 void GrSurfaceProxy::computeScratchKey(GrScratchKey* key) const {
     SkASSERT(LazyState::kFully != this->lazyInstantiationState());
     const GrRenderTargetProxy* rtp = this->asRenderTargetProxy();
-    int sampleCount = 0;
+    int sampleCount = 1;
     if (rtp) {
         sampleCount = rtp->numStencilSamples();
     }
diff --git a/src/gpu/GrTexture.cpp b/src/gpu/GrTexture.cpp
index b4cefb0174..dd0631775f 100644
--- a/src/gpu/GrTexture.cpp
+++ b/src/gpu/GrTexture.cpp
@@ -78,7 +78,7 @@ bool GrTexture::StealBackendTexture(sk_sp<GrTexture>&& texture,
 
 void GrTexture::computeScratchKey(GrScratchKey* key) const {
     const GrRenderTarget* rt = this->asRenderTarget();
-    int sampleCount = 0;
+    int sampleCount = 1;
     if (rt) {
         sampleCount = rt->numStencilSamples();
     }
@@ -92,8 +92,10 @@ void GrTexturePriv::ComputeScratchKey(GrPixelConfig config, int width, int heigh
                                       GrMipMapped mipMapped, GrScratchKey* key) {
     static const GrScratchKey::ResourceType kType = GrScratchKey::GenerateResourceType();
     uint32_t flags = isRenderTarget;
-
-    SkASSERT(0 == sampleCnt || isRenderTarget);
+    SkASSERT(width > 0);
+    SkASSERT(height > 0);
+    SkASSERT(sampleCnt > 0);
+    SkASSERT(1 == sampleCnt || isRenderTarget);
 
     // make sure desc.fConfig fits in 5 bits
     SkASSERT(sk_float_log2(kLast_GrPixelConfig) <= 5);
diff --git a/src/gpu/GrTextureProducer.cpp b/src/gpu/GrTextureProducer.cpp
index 9593cb6873..9b344cb831 100644
--- a/src/gpu/GrTextureProducer.cpp
+++ b/src/gpu/GrTextureProducer.cpp
@@ -25,8 +25,8 @@ sk_sp<GrTextureProxy> GrTextureProducer::CopyOnGpu(GrContext* context,
     GrMipMapped mipMapped = dstWillRequireMipMaps ? GrMipMapped::kYes : GrMipMapped::kNo;
 
     sk_sp<GrRenderTargetContext> copyRTC = context->makeDeferredRenderTargetContextWithFallback(
-        SkBackingFit::kExact, dstRect.width(), dstRect.height(), inputProxy->config(), nullptr,
-        0, mipMapped, inputProxy->origin());
+            SkBackingFit::kExact, dstRect.width(), dstRect.height(), inputProxy->config(), nullptr,
+            1, mipMapped, inputProxy->origin());
     if (!copyRTC) {
         return nullptr;
     }
diff --git a/src/gpu/GrTextureProxy.cpp b/src/gpu/GrTextureProxy.cpp
index 8e6afbf0a7..54d0769a63 100644
--- a/src/gpu/GrTextureProxy.cpp
+++ b/src/gpu/GrTextureProxy.cpp
@@ -64,7 +64,7 @@ bool GrTextureProxy::instantiate(GrResourceProvider* resourceProvider) {
     if (LazyState::kNot != this->lazyInstantiationState()) {
         return false;
     }
-    if (!this->instantiateImpl(resourceProvider, 0, /* needsStencil = */ false,
+    if (!this->instantiateImpl(resourceProvider, 1, /* needsStencil = */ false,
                                kNone_GrSurfaceFlags, fMipMapped, fMipColorMode,
                                fUniqueKey.isValid() ? &fUniqueKey : nullptr)) {
         return false;
@@ -76,7 +76,7 @@ bool GrTextureProxy::instantiate(GrResourceProvider* resourceProvider) {
 }
 
 sk_sp<GrSurface> GrTextureProxy::createSurface(GrResourceProvider* resourceProvider) const {
-    sk_sp<GrSurface> surface= this->createSurfaceImpl(resourceProvider, 0,
+    sk_sp<GrSurface> surface= this->createSurfaceImpl(resourceProvider, 1,
                                                       /* needsStencil = */ false,
                                                       kNone_GrSurfaceFlags,
                                                       fMipMapped, fMipColorMode);
diff --git a/src/gpu/GrTextureRenderTargetProxy.cpp b/src/gpu/GrTextureRenderTargetProxy.cpp
index da8e48307d..843524c062 100644
--- a/src/gpu/GrTextureRenderTargetProxy.cpp
+++ b/src/gpu/GrTextureRenderTargetProxy.cpp
@@ -53,7 +53,11 @@ GrTextureRenderTargetProxy::GrTextureRenderTargetProxy(sk_sp<GrSurface> surf,
 }
 
 size_t GrTextureRenderTargetProxy::onUninstantiatedGpuMemorySize() const {
-    int colorSamplesPerPixel = this->numColorSamples() + 1;
+    int colorSamplesPerPixel = this->numColorSamples();
+    if (colorSamplesPerPixel > 1) {
+        // Add one to account for the resolve buffer.
+        ++colorSamplesPerPixel += 1;
+    }
 
     // TODO: do we have enough information to improve this worst case estimate?
     return GrSurface::ComputeSize(this->config(), this->width(), this->height(),
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index 976339b96f..a702d06395 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -47,7 +47,7 @@ GrSurfaceDesc GrImageInfoToSurfaceDesc(const SkImageInfo& info, const GrCaps& ca
     desc.fWidth = info.width();
     desc.fHeight = info.height();
     desc.fConfig = SkImageInfo2GrPixelConfig(info, caps);
-    desc.fSampleCnt = 0;
+    desc.fSampleCnt = 1;
     return desc;
 }
 
@@ -169,7 +169,7 @@ sk_sp<GrTextureProxy> GrCopyBaseMipMapToTextureProxy(GrContext* ctx, GrTexturePr
     desc.fWidth = baseProxy->width();
     desc.fHeight = baseProxy->height();
     desc.fConfig = baseProxy->config();
-    desc.fSampleCnt = 0;
+    desc.fSampleCnt = 1;
 
     sk_sp<GrTextureProxy> proxy = proxyProvider->createMipMapProxy(desc, SkBudgeted::kYes);
     if (!proxy) {
diff --git a/src/gpu/ddl/GrDDLGpu.h b/src/gpu/ddl/GrDDLGpu.h
index 16deab0353..e1f463f073 100644
--- a/src/gpu/ddl/GrDDLGpu.h
+++ b/src/gpu/ddl/GrDDLGpu.h
@@ -46,7 +46,7 @@ public:
     void onQueryMultisampleSpecs(GrRenderTarget* rt, GrSurfaceOrigin, const GrStencilSettings&,
                                  int* effectiveSampleCnt, SamplePattern*) override {
         SkASSERT(0);
-        *effectiveSampleCnt = 0; // ??
+        *effectiveSampleCnt = 1;  // ??
     }
 
     GrGpuRTCommandBuffer* createCommandBuffer(
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 3b90676be1..93a7e614fd 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -1958,6 +1958,8 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
 
     for (int i = 0; i < kGrPixelConfigCnt; ++i) {
         if (ConfigInfo::kRenderableWithMSAA_Flag & fConfigTable[i].fFlags) {
+            // We assume that MSAA rendering is supported only if we support non-MSAA rendering.
+            SkASSERT(ConfigInfo::kRenderable_Flag & fConfigTable[i].fFlags);
             if ((kGL_GrGLStandard == ctxInfo.standard() &&
                  (ctxInfo.version() >= GR_GL_VER(4,2) ||
                   ctxInfo.hasExtension("GL_ARB_internalformat_query"))) ||
@@ -1970,10 +1972,15 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
                     int* temp = new int[count];
                     GR_GL_GetInternalformativ(gli, GR_GL_RENDERBUFFER, format, GR_GL_SAMPLES, count,
                                               temp);
+                    // GL has a concept of MSAA rasterization with a single sample but we do not.
+                    if (count && temp[count - 1] == 1) {
+                        --count;
+                        SkASSERT(!count || temp[count -1] > 1);
+                    }
                     fConfigTable[i].fColorSampleCounts.setCount(count+1);
-                    // We initialize our supported values with 0 (no msaa) and reverse the order
+                    // We initialize our supported values with 1 (no msaa) and reverse the order
                     // returned by GL so that the array is ascending.
-                    fConfigTable[i].fColorSampleCounts[0] = 0;
+                    fConfigTable[i].fColorSampleCounts[0] = 1;
                     for (int j = 0; j < count; ++j) {
                         fConfigTable[i].fColorSampleCounts[j+1] = temp[count - j - 1];
                     }
@@ -1982,14 +1989,16 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
             } else {
                 // Fake out the table using some semi-standard counts up to the max allowed sample
                 // count.
-                int maxSampleCnt = 0;
+                int maxSampleCnt = 1;
                 if (GrGLCaps::kES_IMG_MsToTexture_MSFBOType == fMSFBOType) {
                     GR_GL_GetIntegerv(gli, GR_GL_MAX_SAMPLES_IMG, &maxSampleCnt);
                 } else if (GrGLCaps::kNone_MSFBOType != fMSFBOType) {
                     GR_GL_GetIntegerv(gli, GR_GL_MAX_SAMPLES, &maxSampleCnt);
                 }
+                // Chrome has a mock GL implementation that returns 0.
+                maxSampleCnt = SkTMax(1, maxSampleCnt);
 
-                static constexpr int kDefaultSamples[] = {0, 1, 2, 4, 8};
+                static constexpr int kDefaultSamples[] = {1, 2, 4, 8};
                 int count = SK_ARRAY_COUNT(kDefaultSamples);
                 for (; count > 0; --count) {
                     if (kDefaultSamples[count - 1] <= maxSampleCnt) {
@@ -2000,6 +2009,9 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
                     fConfigTable[i].fColorSampleCounts.append(count, kDefaultSamples);
                 }
             }
+        } else if (ConfigInfo::kRenderable_Flag & fConfigTable[i].fFlags) {
+            fConfigTable[i].fColorSampleCounts.setCount(1);
+            fConfigTable[i].fColorSampleCounts[0] = 1;
         }
     }
 
@@ -2457,17 +2469,22 @@ void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {
 }
 
 int GrGLCaps::getSampleCount(int requestedCount, GrPixelConfig config) const {
+    requestedCount = SkTMax(1, requestedCount);
     int count = fConfigTable[config].fColorSampleCounts.count();
-    if (!count || !this->isConfigRenderable(config, true)) {
+    if (!count || !this->isConfigRenderable(config, requestedCount > 1)) {
         return 0;
     }
 
+    if (1 == requestedCount) {
+        return fConfigTable[config].fColorSampleCounts[0] == 1 ? 1 : 0;
+    }
+
     for (int i = 0; i < count; ++i) {
         if (fConfigTable[config].fColorSampleCounts[i] >= requestedCount) {
             return fConfigTable[config].fColorSampleCounts[i];
         }
     }
-    return fConfigTable[config].fColorSampleCounts[count-1];
+    return 0;
 }
 
 bool validate_sized_format(GrGLenum format, SkColorType ct, GrPixelConfig* config,
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index ae31495b06..e117488647 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -545,7 +545,7 @@ sk_sp<GrTexture> GrGLGpu::onWrapBackendTexture(const GrBackendTexture& backendTe
     surfDesc.fWidth = backendTex.width();
     surfDesc.fHeight = backendTex.height();
     surfDesc.fConfig = backendTex.config();
-    surfDesc.fSampleCnt = 0;
+    surfDesc.fSampleCnt = 1;
 
     GrMipMapsStatus mipMapsStatus = backendTex.hasMipMaps() ? GrMipMapsStatus::kValid
                                                             : GrMipMapsStatus::kNotAllocated;
@@ -582,6 +582,9 @@ sk_sp<GrTexture> GrGLGpu::onWrapRenderableBackendTexture(const GrBackendTexture&
     surfDesc.fHeight = backendTex.height();
     surfDesc.fConfig = backendTex.config();
     surfDesc.fSampleCnt = this->caps()->getSampleCount(sampleCnt, backendTex.config());
+    if (surfDesc.fSampleCnt < 1) {
+        return nullptr;
+    }
 
     GrGLRenderTarget::IDDesc rtIDDesc;
     if (!this->createRenderTargetObjects(surfDesc, idDesc.fInfo, &rtIDDesc)) {
@@ -686,7 +689,7 @@ bool GrGLGpu::onGetWritePixelsInfo(GrSurface* dstSurface, GrSurfaceOrigin dstOri
     }
 
     // If the dst is MSAA, we have to draw, or we'll just be writing to the resolve target.
-    if (dstSurface->asRenderTarget() && dstSurface->asRenderTarget()->numColorSamples() > 0) {
+    if (dstSurface->asRenderTarget() && dstSurface->asRenderTarget()->numColorSamples() > 1) {
         ElevateDrawPreference(drawPreference, kRequireDraw_DrawPreference);
     }
 
@@ -704,7 +707,7 @@ bool GrGLGpu::onGetWritePixelsInfo(GrSurface* dstSurface, GrSurfaceOrigin dstOri
     tempDrawInfo->fTempSurfaceDesc.fConfig = srcConfig;
     tempDrawInfo->fTempSurfaceDesc.fWidth = width;
     tempDrawInfo->fTempSurfaceDesc.fHeight = height;
-    tempDrawInfo->fTempSurfaceDesc.fSampleCnt = 0;
+    tempDrawInfo->fTempSurfaceDesc.fSampleCnt = 1;
     tempDrawInfo->fTempSurfaceDesc.fOrigin = kTopLeft_GrSurfaceOrigin; // no CPU y-flip for TL.
 
     bool configsAreRBSwaps = GrPixelConfigSwapRAndB(srcConfig) == dstSurface->config();
@@ -1277,13 +1280,13 @@ bool GrGLGpu::createRenderTargetObjects(const GrSurfaceDesc& desc,
     idDesc->fTexFBOID = 0;
     SkASSERT((GrGLCaps::kMixedSamples_MSFBOType == this->glCaps().msFBOType()) ==
              this->caps()->usesMixedSamples());
-    idDesc->fIsMixedSampled = desc.fSampleCnt > 0 && this->caps()->usesMixedSamples();
+    idDesc->fIsMixedSampled = desc.fSampleCnt > 1 && this->caps()->usesMixedSamples();
 
     GrGLenum status;
 
     GrGLenum colorRenderbufferFormat = 0; // suppress warning
 
-    if (desc.fSampleCnt > 0 && GrGLCaps::kNone_MSFBOType == this->glCaps().msFBOType()) {
+    if (desc.fSampleCnt > 1 && GrGLCaps::kNone_MSFBOType == this->glCaps().msFBOType()) {
         goto FAILED;
     }
 
@@ -1296,7 +1299,7 @@ bool GrGLGpu::createRenderTargetObjects(const GrSurfaceDesc& desc,
     // the texture bound to the other. The exception is the IMG multisample extension. With this
     // extension the texture is multisampled when rendered to and then auto-resolves it when it is
     // rendered from.
-    if (desc.fSampleCnt > 0 && this->glCaps().usesMSAARenderBuffers()) {
+    if (desc.fSampleCnt > 1 && this->glCaps().usesMSAARenderBuffers()) {
         GL_CALL(GenFramebuffers(1, &idDesc->fRTFBOID));
         GL_CALL(GenRenderbuffers(1, &idDesc->fMSColorRenderbufferID));
         if (!idDesc->fRTFBOID ||
@@ -1313,7 +1316,7 @@ bool GrGLGpu::createRenderTargetObjects(const GrSurfaceDesc& desc,
     // below here we may bind the FBO
     fHWBoundRenderTargetUniqueID.makeInvalid();
     if (idDesc->fRTFBOID != idDesc->fTexFBOID) {
-        SkASSERT(desc.fSampleCnt > 0);
+        SkASSERT(desc.fSampleCnt > 1);
         GL_CALL(BindRenderbuffer(GR_GL_RENDERBUFFER, idDesc->fMSColorRenderbufferID));
         if (!renderbuffer_storage_msaa(*fGLContext,
                                        desc.fSampleCnt,
@@ -1338,7 +1341,7 @@ bool GrGLGpu::createRenderTargetObjects(const GrSurfaceDesc& desc,
     fStats.incRenderTargetBinds();
     GL_CALL(BindFramebuffer(GR_GL_FRAMEBUFFER, idDesc->fTexFBOID));
 
-    if (this->glCaps().usesImplicitMSAAResolve() && desc.fSampleCnt > 0) {
+    if (this->glCaps().usesImplicitMSAAResolve() && desc.fSampleCnt > 1) {
         GL_CALL(FramebufferTexture2DMultisample(GR_GL_FRAMEBUFFER,
                                                 GR_GL_COLOR_ATTACHMENT0,
                                                 texInfo.fTarget,
@@ -1415,7 +1418,7 @@ sk_sp<GrTexture> GrGLGpu::onCreateTexture(const GrSurfaceDesc& desc,
                                           const GrMipLevel texels[],
                                           int mipLevelCount) {
     // We fail if the MSAA was requested and is not available.
-    if (GrGLCaps::kNone_MSFBOType == this->glCaps().msFBOType() && desc.fSampleCnt) {
+    if (GrGLCaps::kNone_MSFBOType == this->glCaps().msFBOType() && desc.fSampleCnt > 1) {
         //SkDebugf("MSAA RT requested but not supported on this platform.");
         return return_null_texture();
     }
@@ -1694,7 +1697,7 @@ GrStencilAttachment* GrGLGpu::createStencilAttachmentForRenderTarget(const GrRen
     CLEAR_ERROR_BEFORE_ALLOC(this->glInterface());
     // we do this "if" so that we don't call the multisample
     // version on a GL that doesn't have an MSAA extension.
-    if (samples > 0) {
+    if (samples > 1) {
         SkAssertResult(renderbuffer_storage_msaa(*fGLContext,
                                                  samples,
                                                  sFmt.fInternalFormat,
@@ -2194,7 +2197,7 @@ bool GrGLGpu::onGetReadPixelsInfo(GrSurface* srcSurface, GrSurfaceOrigin srcOrig
     tempDrawInfo->fTempSurfaceDesc.fFlags = kRenderTarget_GrSurfaceFlag;
     tempDrawInfo->fTempSurfaceDesc.fWidth = width;
     tempDrawInfo->fTempSurfaceDesc.fHeight = height;
-    tempDrawInfo->fTempSurfaceDesc.fSampleCnt = 0;
+    tempDrawInfo->fTempSurfaceDesc.fSampleCnt = 1;
     tempDrawInfo->fTempSurfaceDesc.fOrigin = kTopLeft_GrSurfaceOrigin; // no CPU y-flip for TL.
     tempDrawInfo->fTempSurfaceFit = this->glCaps().partialFBOReadIsSlow() ? SkBackingFit::kExact
                                                                           : SkBackingFit::kApprox;
@@ -3334,8 +3337,8 @@ static inline bool can_blit_framebuffer_for_copy_surface(
         }
     }
     if (GrGLCaps::kResolveMustBeFull_BlitFrambufferFlag & blitFramebufferFlags) {
-        if (srcRT && srcRT->numColorSamples()) {
-            if (dstRT && !dstRT->numColorSamples()) {
+        if (srcRT && srcRT->numColorSamples() > 1) {
+            if (dstRT && 1 == dstRT->numColorSamples()) {
                 return false;
             }
             if (SkRect::Make(srcRect) != srcRT->getBoundsRect()) {
@@ -3344,7 +3347,7 @@ static inline bool can_blit_framebuffer_for_copy_surface(
         }
     }
     if (GrGLCaps::kNoMSAADst_BlitFramebufferFlag & blitFramebufferFlags) {
-        if (dstRT && dstRT->numColorSamples() > 0) {
+        if (dstRT && dstRT->numColorSamples() > 1) {
             return false;
         }
     }
@@ -3354,12 +3357,12 @@ static inline bool can_blit_framebuffer_for_copy_surface(
         }
     } else if (GrGLCaps::kNoFormatConversionForMSAASrc_BlitFramebufferFlag & blitFramebufferFlags) {
         const GrRenderTarget* srcRT = src->asRenderTarget();
-        if (srcRT && srcRT->numColorSamples() && dst->config() != src->config()) {
+        if (srcRT && srcRT->numColorSamples() > 1 && dst->config() != src->config()) {
             return false;
         }
     }
     if (GrGLCaps::kRectsMustMatchForMSAASrc_BlitFramebufferFlag & blitFramebufferFlags) {
-        if (srcRT && srcRT->numColorSamples()) {
+        if (srcRT && srcRT->numColorSamples() > 1) {
             if (dstPoint.fX != srcRect.fLeft || dstPoint.fY != srcRect.fTop) {
                 return false;
             }
@@ -3376,7 +3379,7 @@ static bool rt_has_msaa_render_buffer(const GrGLRenderTarget* rt, const GrGLCaps
     // 1) It's multisampled
     // 2) We're using an extension with separate MSAA renderbuffers
     // 3) It's not FBO 0, which is special and always auto-resolves
-    return rt->numColorSamples() > 0 && glCaps.usesMSAARenderBuffers() && rt->renderFBOID() != 0;
+    return rt->numColorSamples() > 1 && glCaps.usesMSAARenderBuffers() && rt->renderFBOID() != 0;
 }
 
 static inline bool can_copy_texsubimage(const GrSurface* dst, GrSurfaceOrigin dstOrigin,
diff --git a/src/gpu/gl/GrGLRenderTarget.cpp b/src/gpu/gl/GrGLRenderTarget.cpp
index 443128d4d4..6f3714c504 100644
--- a/src/gpu/gl/GrGLRenderTarget.cpp
+++ b/src/gpu/gl/GrGLRenderTarget.cpp
@@ -224,7 +224,7 @@ int GrGLRenderTarget::msaaSamples() const {
     if (fTexFBOID == kUnresolvableFBOID || fTexFBOID != fRTFBOID) {
         // If the render target's FBO is external (fTexFBOID == kUnresolvableFBOID), or if we own
         // the render target's FBO (fTexFBOID == fRTFBOID) then we use the provided sample count.
-        return SkTMax(1, this->numStencilSamples());
+        return this->numStencilSamples();
     }
 
     // When fTexFBOID == fRTFBOID, we either are not using MSAA, or MSAA is auto resolving, so use
diff --git a/src/gpu/gl/GrGLStencilAttachment.cpp b/src/gpu/gl/GrGLStencilAttachment.cpp
index aa813ed50e..5c07a7d383 100644
--- a/src/gpu/gl/GrGLStencilAttachment.cpp
+++ b/src/gpu/gl/GrGLStencilAttachment.cpp
@@ -14,7 +14,7 @@ size_t GrGLStencilAttachment::onGpuMemorySize() const {
     uint64_t size = this->width();
     size *= this->height();
     size *= fFormat.fTotalBits;
-    size *= SkTMax(1,this->numSamples());
+    size *= this->numSamples();
     return static_cast<size_t>(size / 8);
 }
 
diff --git a/src/gpu/mock/GrMockCaps.h b/src/gpu/mock/GrMockCaps.h
index edec5563c4..399517b0f5 100644
--- a/src/gpu/mock/GrMockCaps.h
+++ b/src/gpu/mock/GrMockCaps.h
@@ -33,8 +33,8 @@ public:
 
         this->applyOptionsOverrides(contextOptions);
     }
-    int getSampleCount(int /*requestCount*/, GrPixelConfig /*config*/) const override {
-        return 0;
+    int getSampleCount(int requestCount, GrPixelConfig /*config*/) const override {
+        return (requestCount > 0 && requestCount <= 16) ? GrNextPow2(requestCount) : 0;
     }
     bool isConfigTexturable(GrPixelConfig config) const override {
         return fOptions.fConfigOptions[config].fTexturable;
diff --git a/src/gpu/mock/GrMockTexture.h b/src/gpu/mock/GrMockTexture.h
index 9b6501a3c4..b5cc4a27c0 100644
--- a/src/gpu/mock/GrMockTexture.h
+++ b/src/gpu/mock/GrMockTexture.h
@@ -90,8 +90,11 @@ private:
     }
 
     size_t onGpuMemorySize() const override {
-        // The plus 1 is to account for the resolve texture.
-        int numColorSamples = this->numColorSamples() + 1;
+        int numColorSamples = this->numColorSamples();
+        if (numColorSamples > 1) {
+            // Add one to account for the resolve buffer.
+            ++numColorSamples;
+        }
         return GrSurface::ComputeSize(this->config(), this->width(), this->height(),
                                       numColorSamples,
                                       this->texturePriv().mipMapped());
diff --git a/src/gpu/vk/GrVkCaps.cpp b/src/gpu/vk/GrVkCaps.cpp
index 0ae7c00995..e9f239c294 100644
--- a/src/gpu/vk/GrVkCaps.cpp
+++ b/src/gpu/vk/GrVkCaps.cpp
@@ -346,7 +346,7 @@ void GrVkCaps::ConfigInfo::initSampleCounts(const GrVkInterface* interface,
                                                                  &properties));
     VkSampleCountFlags flags = properties.sampleCounts;
     if (flags & VK_SAMPLE_COUNT_1_BIT) {
-        fColorSampleCounts.push(0);
+        fColorSampleCounts.push(1);
     }
     if (kImagination_VkVendor == physProps.vendorID) {
         // MSAA does not work on imagination
@@ -386,18 +386,39 @@ void GrVkCaps::ConfigInfo::init(const GrVkInterface* interface,
     }
 }
 
+bool GrVkCaps::isConfigRenderable(GrPixelConfig config, bool withMSAA) const {
+    if (!SkToBool(ConfigInfo::kRenderable_Flag & fConfigTable[config].fOptimalFlags)) {
+        return false;
+    }
+    if (withMSAA && fConfigTable[config].fColorSampleCounts.count() < 2) {
+        // We expect any renderable config to support non-MSAA rendering.
+        SkASSERT(1 == fConfigTable[config].fColorSampleCounts.count());
+        SkASSERT(1 == fConfigTable[config].fColorSampleCounts[0]);
+        return false;
+    }
+    return true;
+}
+
 int GrVkCaps::getSampleCount(int requestedCount, GrPixelConfig config) const {
+    requestedCount = SkTMax(1, requestedCount);
     int count = fConfigTable[config].fColorSampleCounts.count();
-    if (!count || !this->isConfigRenderable(config, true)) {
+
+    if (!count || !this->isConfigRenderable(config, requestedCount > 1)) {
         return 0;
     }
 
+    if (1 == requestedCount) {
+        SkASSERT(fConfigTable[config].fColorSampleCounts.count() &&
+                 fConfigTable[config].fColorSampleCounts[0] == 1);
+        return 1;
+    }
+
     for (int i = 0; i < count; ++i) {
         if (fConfigTable[config].fColorSampleCounts[i] >= requestedCount) {
             return fConfigTable[config].fColorSampleCounts[i];
         }
     }
-    return fConfigTable[config].fColorSampleCounts[count-1];
+    return 0;
 }
 
 bool validate_image_info(const GrVkImageInfo* imageInfo, SkColorType ct, GrPixelConfig* config) {
diff --git a/src/gpu/vk/GrVkCaps.h b/src/gpu/vk/GrVkCaps.h
index d63c2ba9b5..4468d89697 100644
--- a/src/gpu/vk/GrVkCaps.h
+++ b/src/gpu/vk/GrVkCaps.h
@@ -35,9 +35,7 @@ public:
         return SkToBool(ConfigInfo::kTextureable_Flag & fConfigTable[config].fOptimalFlags);
     }
 
-    bool isConfigRenderable(GrPixelConfig config, bool withMSAA) const override {
-        return SkToBool(ConfigInfo::kRenderable_Flag & fConfigTable[config].fOptimalFlags);
-    }
+    bool isConfigRenderable(GrPixelConfig config, bool withMSAA) const override;
 
     bool isConfigCopyable(GrPixelConfig config) const override {
         return true;
diff --git a/src/gpu/vk/GrVkGpu.cpp b/src/gpu/vk/GrVkGpu.cpp
index f7e3d47dd9..4550dfe1ed 100644
--- a/src/gpu/vk/GrVkGpu.cpp
+++ b/src/gpu/vk/GrVkGpu.cpp
@@ -352,7 +352,7 @@ bool GrVkGpu::onGetWritePixelsInfo(GrSurface* dstSurface, GrSurfaceOrigin dstOri
     tempDrawInfo->fTempSurfaceDesc.fConfig = srcConfig;
     tempDrawInfo->fTempSurfaceDesc.fWidth = width;
     tempDrawInfo->fTempSurfaceDesc.fHeight = height;
-    tempDrawInfo->fTempSurfaceDesc.fSampleCnt = 0;
+    tempDrawInfo->fTempSurfaceDesc.fSampleCnt = 1;
     tempDrawInfo->fTempSurfaceDesc.fOrigin = kTopLeft_GrSurfaceOrigin;
 
     if (dstSurface->config() == srcConfig) {
@@ -914,7 +914,7 @@ sk_sp<GrTexture> GrVkGpu::onWrapBackendTexture(const GrBackendTexture& backendTe
     surfDesc.fWidth = backendTex.width();
     surfDesc.fHeight = backendTex.height();
     surfDesc.fConfig = backendTex.config();
-    surfDesc.fSampleCnt = 0;
+    surfDesc.fSampleCnt = 1;
 
     return GrVkTexture::MakeWrappedTexture(this, surfDesc, ownership, backendTex.getVkImageInfo());
 }
@@ -943,7 +943,7 @@ sk_sp<GrRenderTarget> GrVkGpu::onWrapBackendRenderTarget(const GrBackendRenderTa
     // general this is not an issue since swapchain images in vulkan are never multisampled. Thus if
     // you want a multisampled RT it is best to wrap the swapchain images and then let Skia handle
     // creating and owning the MSAA images.
-    if (backendRT.sampleCnt()) {
+    if (backendRT.sampleCnt() > 1) {
         return nullptr;
     }
 
@@ -961,7 +961,7 @@ sk_sp<GrRenderTarget> GrVkGpu::onWrapBackendRenderTarget(const GrBackendRenderTa
     desc.fWidth = backendRT.width();
     desc.fHeight = backendRT.height();
     desc.fConfig = backendRT.config();
-    desc.fSampleCnt = 0;
+    desc.fSampleCnt = 1;
 
     sk_sp<GrVkRenderTarget> tgt = GrVkRenderTarget::MakeWrappedRenderTarget(this, desc, info);
     if (tgt && backendRT.stencilBits()) {
@@ -990,6 +990,9 @@ sk_sp<GrRenderTarget> GrVkGpu::onWrapBackendTextureAsRenderTarget(const GrBacken
     desc.fHeight = tex.height();
     desc.fConfig = tex.config();
     desc.fSampleCnt = this->caps()->getSampleCount(sampleCnt, tex.config());
+    if (!desc.fSampleCnt) {
+        return nullptr;
+    }
 
     sk_sp<GrVkRenderTarget> tgt = GrVkRenderTarget::MakeWrappedRenderTarget(this, desc, info);
     return tgt;
@@ -1796,7 +1799,7 @@ inline bool can_copy_as_resolve(const GrSurface* dst, GrSurfaceOrigin dstOrigin,
                                 const GrSurface* src, GrSurfaceOrigin srcOrigin,
                                 const GrVkGpu* gpu) {
     // Our src must be a multisampled render target
-    if (!src->asRenderTarget() || src->asRenderTarget()->numColorSamples() <= 1) {
+    if (!src->asRenderTarget() || 1 == src->asRenderTarget()->numColorSamples()) {
         return false;
     }
 
@@ -1894,7 +1897,7 @@ bool GrVkGpu::onGetReadPixelsInfo(GrSurface* srcSurface, GrSurfaceOrigin srcOrig
     tempDrawInfo->fTempSurfaceDesc.fFlags = kRenderTarget_GrSurfaceFlag;
     tempDrawInfo->fTempSurfaceDesc.fWidth = width;
     tempDrawInfo->fTempSurfaceDesc.fHeight = height;
-    tempDrawInfo->fTempSurfaceDesc.fSampleCnt = 0;
+    tempDrawInfo->fTempSurfaceDesc.fSampleCnt = 1;
     tempDrawInfo->fTempSurfaceDesc.fOrigin = kTopLeft_GrSurfaceOrigin; // no CPU y-flip for TL.
     tempDrawInfo->fTempSurfaceFit = SkBackingFit::kApprox;
 
diff --git a/src/gpu/vk/GrVkRenderTarget.cpp b/src/gpu/vk/GrVkRenderTarget.cpp
index c5a8628cc4..2a745ed51c 100644
--- a/src/gpu/vk/GrVkRenderTarget.cpp
+++ b/src/gpu/vk/GrVkRenderTarget.cpp
@@ -39,7 +39,7 @@ GrVkRenderTarget::GrVkRenderTarget(GrVkGpu* gpu,
     , fResolveAttachmentView(resolveAttachmentView)
     , fFramebuffer(nullptr)
     , fCachedSimpleRenderPass(nullptr) {
-    SkASSERT(desc.fSampleCnt);
+    SkASSERT(desc.fSampleCnt > 1);
     this->createFramebuffer(gpu);
     this->registerWithCache(budgeted);
 }
@@ -62,7 +62,7 @@ GrVkRenderTarget::GrVkRenderTarget(GrVkGpu* gpu,
     , fResolveAttachmentView(resolveAttachmentView)
     , fFramebuffer(nullptr)
     , fCachedSimpleRenderPass(nullptr) {
-    SkASSERT(desc.fSampleCnt);
+    SkASSERT(desc.fSampleCnt > 1);
     this->createFramebuffer(gpu);
 }
 
@@ -82,7 +82,7 @@ GrVkRenderTarget::GrVkRenderTarget(GrVkGpu* gpu,
     , fResolveAttachmentView(nullptr)
     , fFramebuffer(nullptr)
     , fCachedSimpleRenderPass(nullptr) {
-    SkASSERT(!desc.fSampleCnt);
+    SkASSERT(1 == desc.fSampleCnt);
     this->createFramebuffer(gpu);
     this->registerWithCache(budgeted);
 }
@@ -102,7 +102,7 @@ GrVkRenderTarget::GrVkRenderTarget(GrVkGpu* gpu,
     , fResolveAttachmentView(nullptr)
     , fFramebuffer(nullptr)
     , fCachedSimpleRenderPass(nullptr) {
-    SkASSERT(!desc.fSampleCnt);
+    SkASSERT(1 == desc.fSampleCnt);
     this->createFramebuffer(gpu);
 }
 
@@ -121,7 +121,7 @@ GrVkRenderTarget::Create(GrVkGpu* gpu,
     // create msaa surface if necessary
     GrVkImageInfo msInfo;
     const GrVkImageView* resolveAttachmentView = nullptr;
-    if (desc.fSampleCnt) {
+    if (desc.fSampleCnt > 1) {
         GrVkImage::ImageDesc msImageDesc;
         msImageDesc.fImageType = VK_IMAGE_TYPE_2D;
         msImageDesc.fFormat = pixelFormat;
@@ -158,7 +158,7 @@ GrVkRenderTarget::Create(GrVkGpu* gpu,
     const GrVkImageView* colorAttachmentView = GrVkImageView::Create(gpu, colorImage, pixelFormat,
                                                                      GrVkImageView::kColor_Type, 1);
     if (!colorAttachmentView) {
-        if (desc.fSampleCnt) {
+        if (desc.fSampleCnt > 1) {
             resolveAttachmentView->unref(gpu);
             GrVkImage::DestroyImageInfo(gpu, &msInfo);
         }
@@ -166,7 +166,7 @@ GrVkRenderTarget::Create(GrVkGpu* gpu,
     }
 
     GrVkRenderTarget* texRT;
-    if (desc.fSampleCnt) {
+    if (desc.fSampleCnt > 1) {
         texRT = new GrVkRenderTarget(gpu, budgeted, desc, info, msInfo,
                                      colorAttachmentView, resolveAttachmentView, ownership);
     } else {
@@ -237,11 +237,10 @@ void GrVkRenderTarget::createFramebuffer(GrVkGpu* gpu) {
 void GrVkRenderTarget::getAttachmentsDescriptor(
                                            GrVkRenderPass::AttachmentsDescriptor* desc,
                                            GrVkRenderPass::AttachmentFlags* attachmentFlags) const {
-    int colorSamples = this->numColorSamples();
     VkFormat colorFormat;
     GrPixelConfigToVkFormat(this->config(), &colorFormat);
     desc->fColor.fFormat = colorFormat;
-    desc->fColor.fSamples = colorSamples ? colorSamples : 1;
+    desc->fColor.fSamples = this->numColorSamples();
     *attachmentFlags = GrVkRenderPass::kColor_AttachmentFlag;
     uint32_t attachmentCount = 1;
 
@@ -249,7 +248,7 @@ void GrVkRenderTarget::getAttachmentsDescriptor(
     if (stencil) {
         const GrVkStencilAttachment* vkStencil = static_cast<const GrVkStencilAttachment*>(stencil);
         desc->fStencil.fFormat = vkStencil->vkFormat();
-        desc->fStencil.fSamples = vkStencil->numSamples() ? vkStencil->numSamples() : 1;
+        desc->fStencil.fSamples = vkStencil->numSamples();
         // Currently in vulkan stencil and color attachments must all have same number of samples
         SkASSERT(desc->fColor.fSamples == desc->fStencil.fSamples);
         *attachmentFlags |= GrVkRenderPass::kStencil_AttachmentFlag;
diff --git a/src/gpu/vk/GrVkRenderTarget.h b/src/gpu/vk/GrVkRenderTarget.h
index eb297a8a1d..bea90a759b 100644
--- a/src/gpu/vk/GrVkRenderTarget.h
+++ b/src/gpu/vk/GrVkRenderTarget.h
@@ -99,8 +99,11 @@ protected:
 
     // This accounts for the texture's memory and any MSAA renderbuffer's memory.
     size_t onGpuMemorySize() const override {
-        // The plus 1 is to account for the resolve texture or if not using msaa the RT itself
-        int numColorSamples = this->numColorSamples() + 1;
+        int numColorSamples = this->numColorSamples();
+        if (numColorSamples > 1) {
+            // Add one to account for the resolved  VkImage.
+            numColorSamples += 1;
+        }
         return GrSurface::ComputeSize(this->config(), this->width(), this->height(),
                                       numColorSamples, GrMipMapped::kNo);
     }
diff --git a/src/gpu/vk/GrVkStencilAttachment.cpp b/src/gpu/vk/GrVkStencilAttachment.cpp
index 5348885a6b..139c00f3b2 100644
--- a/src/gpu/vk/GrVkStencilAttachment.cpp
+++ b/src/gpu/vk/GrVkStencilAttachment.cpp
@@ -72,7 +72,7 @@ size_t GrVkStencilAttachment::onGpuMemorySize() const {
     uint64_t size = this->width();
     size *= this->height();
     size *= fFormat.fTotalBits;
-    size *= SkTMax(1,this->numSamples());
+    size *= this->numSamples();
     return static_cast<size_t>(size / 8);
 }
 
diff --git a/src/gpu/vk/GrVkTextureRenderTarget.cpp b/src/gpu/vk/GrVkTextureRenderTarget.cpp
index 9a211e208a..ee31f2364a 100644
--- a/src/gpu/vk/GrVkTextureRenderTarget.cpp
+++ b/src/gpu/vk/GrVkTextureRenderTarget.cpp
@@ -106,7 +106,7 @@ sk_sp<GrVkTextureRenderTarget> GrVkTextureRenderTarget::Make(GrVkGpu* gpu,
     // create msaa surface if necessary
     GrVkImageInfo msInfo;
     const GrVkImageView* resolveAttachmentView = nullptr;
-    if (desc.fSampleCnt) {
+    if (desc.fSampleCnt > 1) {
         GrVkImage::ImageDesc msImageDesc;
         msImageDesc.fImageType = VK_IMAGE_TYPE_2D;
         msImageDesc.fFormat = pixelFormat;
@@ -145,7 +145,7 @@ sk_sp<GrVkTextureRenderTarget> GrVkTextureRenderTarget::Make(GrVkGpu* gpu,
     const GrVkImageView* colorAttachmentView = GrVkImageView::Create(gpu, colorImage, pixelFormat,
                                                                      GrVkImageView::kColor_Type, 1);
     if (!colorAttachmentView) {
-        if (desc.fSampleCnt) {
+        if (desc.fSampleCnt > 1) {
             resolveAttachmentView->unref(gpu);
             GrVkImage::DestroyImageInfo(gpu, &msInfo);
         }
@@ -154,7 +154,7 @@ sk_sp<GrVkTextureRenderTarget> GrVkTextureRenderTarget::Make(GrVkGpu* gpu,
     }
 
     sk_sp<GrVkTextureRenderTarget> texRT;
-    if (desc.fSampleCnt) {
+    if (desc.fSampleCnt > 1) {
         if (!isWrapped) {
             texRT = sk_sp<GrVkTextureRenderTarget>(new GrVkTextureRenderTarget(
                                                       gpu, budgeted, desc,
@@ -232,7 +232,7 @@ GrVkTextureRenderTarget::MakeWrappedTextureRenderTarget(GrVkGpu* gpu,
 bool GrVkTextureRenderTarget::updateForMipmap(GrVkGpu* gpu, const GrVkImageInfo& newInfo) {
     VkFormat pixelFormat;
     GrPixelConfigToVkFormat(this->config(), &pixelFormat);
-    if (this->numStencilSamples()) {
+    if (this->numStencilSamples() > 1) {
         const GrVkImageView* resolveAttachmentView =
                 GrVkImageView::Create(gpu,
                                       newInfo.fImage,
@@ -262,8 +262,11 @@ bool GrVkTextureRenderTarget::updateForMipmap(GrVkGpu* gpu, const GrVkImageInfo&
 }
 
 size_t GrVkTextureRenderTarget::onGpuMemorySize() const {
-    // The plus 1 is to account for the resolve texture.
-    int numColorSamples = this->numColorSamples() + 1;
+    int numColorSamples = this->numColorSamples();
+    if (numColorSamples > 1) {
+        // Add one to account for the resolve VkImage.
+        ++numColorSamples;
+    }
     return GrSurface::ComputeSize(this->config(), this->width(), this->height(),
                                   numColorSamples,  // TODO: this still correct?
                                   this->texturePriv().mipMapped());
diff --git a/src/gpu/vk/GrVkUtil.cpp b/src/gpu/vk/GrVkUtil.cpp
index cb0046e58c..12db4c111e 100644
--- a/src/gpu/vk/GrVkUtil.cpp
+++ b/src/gpu/vk/GrVkUtil.cpp
@@ -263,8 +263,8 @@ bool GrVkFormatIsSRGB(VkFormat format, VkFormat* linearFormat) {
 }
 
 bool GrSampleCountToVkSampleCount(uint32_t samples, VkSampleCountFlagBits* vkSamples) {
+    SkASSERT(samples >= 1);
     switch (samples) {
-        case 0: // fall through
         case 1:
             *vkSamples = VK_SAMPLE_COUNT_1_BIT;
             return true;
diff --git a/src/image/SkImage_Gpu.cpp b/src/image/SkImage_Gpu.cpp
index c00c50d000..a136c7b49c 100644
--- a/src/image/SkImage_Gpu.cpp
+++ b/src/image/SkImage_Gpu.cpp
@@ -438,13 +438,8 @@ static sk_sp<SkImage> make_from_yuv_textures_copy(GrContext* ctx, SkYUVColorSpac
 
     // Needs to be a render target in order to draw to it for the yuv->rgb conversion.
     sk_sp<GrRenderTargetContext> renderTargetContext(ctx->makeDeferredRenderTargetContext(
-                                                                         SkBackingFit::kExact,
-                                                                         width, height,
-                                                                         kRGBA_8888_GrPixelConfig,
-                                                                         std::move(imageColorSpace),
-                                                                         0,
-                                                                         GrMipMapped::kNo,
-                                                                         origin));
+            SkBackingFit::kExact, width, height, kRGBA_8888_GrPixelConfig,
+            std::move(imageColorSpace), 1, GrMipMapped::kNo, origin));
     if (!renderTargetContext) {
         return nullptr;
     }
diff --git a/src/image/SkSurface.cpp b/src/image/SkSurface.cpp
index 0a684cce60..ef6d809957 100644
--- a/src/image/SkSurface.cpp
+++ b/src/image/SkSurface.cpp
@@ -247,8 +247,8 @@ sk_sp<SkSurface> SkSurface::MakeNull(int width, int height) {
 
 #if !SK_SUPPORT_GPU
 
-sk_sp<SkSurface> SkSurface::MakeRenderTarget(GrContext*, SkBudgeted, const SkImageInfo&,
-                                             int, GrSurfaceOrigin, const SkSurfaceProps*, bool) {
+sk_sp<SkSurface> SkSurface::MakeRenderTarget(GrContext*, SkBudgeted, const SkImageInfo&, int,
+                                             GrSurfaceOrigin, const SkSurfaceProps*, bool) {
     return nullptr;
 }
 
diff --git a/src/image/SkSurface_Gpu.cpp b/src/image/SkSurface_Gpu.cpp
index 9f7ec3b7f5..e811c3a72f 100644
--- a/src/image/SkSurface_Gpu.cpp
+++ b/src/image/SkSurface_Gpu.cpp
@@ -256,7 +256,7 @@ sk_sp<SkSurface> SkSurface::MakeRenderTarget(GrContext* ctx, SkBudgeted budgeted
     if (!SkSurface_Gpu::Valid(info)) {
         return nullptr;
     }
-
+    sampleCount = SkTMax(1, sampleCount);
     GrMipMapped mipMapped = shouldCreateWithMips ? GrMipMapped::kYes : GrMipMapped::kNo;
 
     if (!ctx->caps()->mipMapSupport()) {
@@ -299,6 +299,7 @@ sk_sp<SkSurface> SkSurface::MakeFromBackendTexture(GrContext* context, const GrB
     if (!SkSurface_Gpu::Valid(context, tex.config(), colorSpace.get())) {
         return nullptr;
     }
+    sampleCnt = SkTMax(1, sampleCnt);
 
     sk_sp<GrRenderTargetContext> rtc(context->contextPriv().makeBackendTextureRenderTargetContext(
                                                                     tex,
@@ -333,7 +334,7 @@ bool validate_backend_texture(GrContext* ctx, const GrBackendTexture& tex, GrPix
         return false;
     }
 
-    if (!ctx->caps()->isConfigRenderable(*config, sampleCnt > 0)) {
+    if (!ctx->caps()->isConfigRenderable(*config, sampleCnt > 1)) {
         return false;
     }
 
@@ -355,6 +356,7 @@ sk_sp<SkSurface> SkSurface::MakeFromBackendTexture(GrContext* context, const GrB
     if (!context) {
         return nullptr;
     }
+    sampleCnt = SkTMax(1, sampleCnt);
     GrBackendTexture texCopy = tex;
     if (!validate_backend_texture(context, texCopy, &texCopy.fConfig,
                                   sampleCnt, colorType, colorSpace, true)) {
@@ -445,6 +447,7 @@ sk_sp<SkSurface> SkSurface::MakeFromBackendTextureAsRenderTarget(GrContext* cont
     if (!SkSurface_Gpu::Valid(context, tex.config(), colorSpace.get())) {
         return nullptr;
     }
+    sampleCnt = SkTMax(1, sampleCnt);
 
     sk_sp<GrRenderTargetContext> rtc(
         context->contextPriv().makeBackendTextureAsRenderTargetRenderTargetContext(
@@ -475,6 +478,7 @@ sk_sp<SkSurface> SkSurface::MakeFromBackendTextureAsRenderTarget(GrContext* cont
     if (!context) {
         return nullptr;
     }
+    sampleCnt = SkTMax(1, sampleCnt);
     GrBackendTexture texCopy = tex;
     if (!validate_backend_texture(context, texCopy, &texCopy.fConfig,
                                   sampleCnt, colorType, colorSpace, false)) {
diff --git a/src/utils/win/SkWGL.h b/src/utils/win/SkWGL.h
index c6c9479abe..cd19f2eeba 100644
--- a/src/utils/win/SkWGL.h
+++ b/src/utils/win/SkWGL.h
@@ -83,7 +83,8 @@ public:
      * priority are:
      *     * Choose formats with the smallest sample count that is >=
      *       desiredSampleCount (or the largest sample count if all formats have
-     *       fewer samples than desiredSampleCount.)
+     *       fewer samples than desiredSampleCount.) If desiredSampleCount is 1 then
+     *       all msaa formats are excluded from consideration.
      *     * Choose formats with the fewest color samples when coverage sampling
      *       is available.
      *     * If the above rules leave multiple formats, choose the one that
@@ -130,8 +131,9 @@ enum SkWGLContextRequest {
 /**
  * Helper to create an OpenGL context for a DC using WGL. Configs with a sample count >= to
  * msaaSampleCount are preferred but if none is available then a context with a lower sample count
- * (including non-MSAA) will be created. If preferCoreProfile is true but a core profile cannot be
- * created then a compatible profile context will be created.
+ * (including non-MSAA) will be created. If msaaSampleCount is 1 then this will fail if a non-msaa
+ * context cannot be created. If preferCoreProfile is true but a core profile cannot be created
+ * then a compatible profile context will be created.
  */
 HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, bool deepColor, SkWGLContextRequest context,
                          HGLRC shareContext = nullptr);
diff --git a/src/utils/win/SkWGL_win.cpp b/src/utils/win/SkWGL_win.cpp
index b7c89944e0..441d7a4ebb 100644
--- a/src/utils/win/SkWGL_win.cpp
+++ b/src/utils/win/SkWGL_win.cpp
@@ -126,6 +126,7 @@ int SkWGLExtensions::selectFormat(const int formats[],
                                   int formatCount,
                                   HDC dc,
                                   int desiredSampleCount) const {
+    SkASSERT(desiredSampleCount >= 1);
     if (formatCount <= 0) {
         return -1;
     }
@@ -146,7 +147,7 @@ int SkWGLExtensions::selectFormat(const int formats[],
                                      &kQueryAttr,
                                      &numSamples);
         rankedFormats[i].fFormat =  formats[i];
-        rankedFormats[i].fSampleCnt = numSamples;
+        rankedFormats[i].fSampleCnt = SkTMax(1, numSamples);
         rankedFormats[i].fChoosePixelFormatRank = i;
     }
     SkTQSort(rankedFormats.begin(),
@@ -159,6 +160,10 @@ int SkWGLExtensions::selectFormat(const int formats[],
     if (idx < 0) {
         idx = ~idx;
     }
+    // If the caller asked for non-MSAA fail if the closest format has MSAA.
+    if (desiredSampleCount == 1 && rankedFormats[idx].fSampleCnt != 1) {
+        return -1;
+    }
     return rankedFormats[idx].fFormat;
 }
 
diff --git a/tests/BlendTest.cpp b/tests/BlendTest.cpp
index b17b9f1e45..3ac7e3c41c 100644
--- a/tests/BlendTest.cpp
+++ b/tests/BlendTest.cpp
@@ -140,7 +140,7 @@ DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(ES2BlendWithNoTexture, reporter, ctxInfo)
     std::vector<TestCase> testCases;
 
     for (auto origin : { kTopLeft_GrSurfaceOrigin, kBottomLeft_GrSurfaceOrigin}) {
-        for (int sampleCnt : {0, 4}) {
+        for (int sampleCnt : {1, 4}) {
             for (auto rectAndPoints : allRectsAndPoints) {
                 for (auto clip : {SkRect::MakeXYWH(0, 0, 10, 10), SkRect::MakeXYWH(1, 1, 8, 8)}) {
                     testCases.push_back({rectAndPoints, clip, sampleCnt, origin});
@@ -162,7 +162,7 @@ DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(ES2BlendWithNoTexture, reporter, ctxInfo)
         sk_sp<SkSurface> surface = create_gpu_surface_backend_texture_as_render_target(
                 context, sampleCnt, kWidth, kHeight, kColorType, kConfig, origin, &backingSurface);
 
-        if (!surface && sampleCnt > 0) {
+        if (!surface && sampleCnt > 1) {
             // Some platforms don't support MSAA.
             continue;
         }
diff --git a/tests/DeferredDisplayListTest.cpp b/tests/DeferredDisplayListTest.cpp
index 8ee24be89a..778714282a 100644
--- a/tests/DeferredDisplayListTest.cpp
+++ b/tests/DeferredDisplayListTest.cpp
@@ -31,9 +31,8 @@ public:
             , fOrigin(kTopLeft_GrSurfaceOrigin)
             , fColorType(kRGBA_8888_SkColorType)
             , fColorSpace(SkColorSpace::MakeSRGB())
-            , fSampleCount(0)
-            , fSurfaceProps(0x0, kUnknown_SkPixelGeometry) {
-    }
+            , fSampleCount(1)
+            , fSurfaceProps(0x0, kUnknown_SkPixelGeometry) {}
 
     int sampleCount() const { return fSampleCount; }
 
@@ -134,7 +133,7 @@ DEF_GPUTEST_FOR_ALL_CONTEXTS(SkSurfaceCharacterization, reporter, ctxInfo) {
             int supportedSampleCount = context->caps()->getSampleCount(
                 params.sampleCount(),
                 gpuSurf->getDevice()->accessRenderTargetContext()->asRenderTargetProxy()->config());
-            if (0 == supportedSampleCount) {
+            if (1 == supportedSampleCount) {
                 // If changing the sample count won't result in a different
                 // surface characterization, skip this step
                 continue;
diff --git a/tests/DeviceTest.cpp b/tests/DeviceTest.cpp
index 64b83fcb3c..58369cc149 100644
--- a/tests/DeviceTest.cpp
+++ b/tests/DeviceTest.cpp
@@ -81,7 +81,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(SpecialImage_GPUDevice, reporter, ctxInfo) {
     SkImageInfo ii = SkImageInfo::MakeN32Premul(2*kWidth, 2*kHeight);
 
     sk_sp<SkBaseDevice> gpuDev(SkGpuDevice::Make(context, SkBudgeted::kNo, ii,
-                                                 0, kBottomLeft_GrSurfaceOrigin, nullptr,
+                                                 1, kBottomLeft_GrSurfaceOrigin, nullptr,
                                                  GrMipMapped::kNo,
                                                  SkGpuDevice::kClear_InitContents));
 
diff --git a/tests/EGLImageTest.cpp b/tests/EGLImageTest.cpp
index dac78a89c0..b0631d0b3c 100644
--- a/tests/EGLImageTest.cpp
+++ b/tests/EGLImageTest.cpp
@@ -163,7 +163,7 @@ DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(EGLImageTest, reporter, ctxInfo) {
     {
         sk_sp<GrRenderTargetContext> temp =
                 context0->contextPriv().makeBackendTextureRenderTargetContext(
-                        backendTex, kBottomLeft_GrSurfaceOrigin, 0, nullptr);
+                        backendTex, kBottomLeft_GrSurfaceOrigin, 1, nullptr);
         if (temp) {
             ERRORF(reporter, "Should not be able to wrap an EXTERNAL texture as a RT.");
         }
diff --git a/tests/GLProgramsTest.cpp b/tests/GLProgramsTest.cpp
index 6c2e8d2f04..df35559b25 100644
--- a/tests/GLProgramsTest.cpp
+++ b/tests/GLProgramsTest.cpp
@@ -150,7 +150,9 @@ static sk_sp<GrRenderTargetContext> random_render_target_context(GrContext* cont
                                                                  const GrCaps* caps) {
     GrSurfaceOrigin origin = random->nextBool() ? kTopLeft_GrSurfaceOrigin
                                                 : kBottomLeft_GrSurfaceOrigin;
-    int sampleCnt = random->nextBool() ? caps->getSampleCount(4, kRGBA_8888_GrPixelConfig) : 0;
+    int sampleCnt = random->nextBool() ? caps->getSampleCount(2, kRGBA_8888_GrPixelConfig) : 1;
+    // Above could be 0 if msaa isn't supported.
+    sampleCnt = SkTMax(1, sampleCnt);
 
     sk_sp<GrRenderTargetContext> renderTargetContext(context->makeDeferredRenderTargetContext(
                                                                            SkBackingFit::kExact,
diff --git a/tests/GpuDrawPathTest.cpp b/tests/GpuDrawPathTest.cpp
index 012dc61cb8..79afa63f2d 100644
--- a/tests/GpuDrawPathTest.cpp
+++ b/tests/GpuDrawPathTest.cpp
@@ -78,7 +78,7 @@ static void test_drawSameRectOvals(skiatest::Reporter*, SkCanvas* canvas) {
 
 DEF_GPUTEST_FOR_ALL_GL_CONTEXTS(GpuDrawPath, reporter, ctxInfo) {
     for (auto& test_func : { &test_drawPathEmpty, &test_drawSameRectOvals }) {
-        for (auto& sampleCount : {0, 4, 16}) {
+        for (auto& sampleCount : {1, 4, 16}) {
             SkImageInfo info = SkImageInfo::MakeN32Premul(255, 255);
             auto surface(
                 SkSurface::MakeRenderTarget(ctxInfo.grContext(), SkBudgeted::kNo, info,
diff --git a/tests/GpuSampleLocationsTest.cpp b/tests/GpuSampleLocationsTest.cpp
index de15e03389..5530539e68 100644
--- a/tests/GpuSampleLocationsTest.cpp
+++ b/tests/GpuSampleLocationsTest.cpp
@@ -109,22 +109,36 @@ void assert_equal(skiatest::Reporter* reporter, const SamplePattern& pattern,
     }
 }
 
+static int pick_random_sample_count(int testPatternSize, SkRandom* rand, const GrCaps* caps) {
+    GrAlwaysAssert(testPatternSize > 1 && SkIsPow2(testPatternSize));
+    int randSampCnt = rand->nextRangeU(1 + testPatternSize / 2, testPatternSize);
+    do {
+        int cnt = caps->getSampleCount(randSampCnt, kRGBA_8888_GrPixelConfig);
+        if (cnt) {
+            return cnt;
+        }
+        --randSampCnt;
+    } while (randSampCnt);
+    // This test assumes an MSAA kRGBA_8888 RTC can be created.
+    GrAlwaysAssert(false);
+    return 0;
+}
+
 void test_sampleLocations(skiatest::Reporter* reporter, TestSampleLocationsInterface* testInterface,
                           GrContext* ctx) {
     SkRandom rand;
     sk_sp<GrRenderTargetContext> bottomUps[numTestPatterns];
     sk_sp<GrRenderTargetContext> topDowns[numTestPatterns];
     for (int i = 0; i < numTestPatterns; ++i) {
-        int numSamples = (int)kTestPatterns[i].size();
-        GrAlwaysAssert(numSamples > 1 && SkIsPow2(numSamples));
+        int patternSize = (int)kTestPatterns[i].size();
+        int randNumSamples = pick_random_sample_count(patternSize, &rand, ctx->caps());
         bottomUps[i] = ctx->makeDeferredRenderTargetContext(
-                           SkBackingFit::kExact, 100, 100, kRGBA_8888_GrPixelConfig, nullptr,
-                           rand.nextRangeU(1 + numSamples / 2, numSamples), GrMipMapped::kNo,
-                           kBottomLeft_GrSurfaceOrigin);
+                SkBackingFit::kExact, 100, 100, kRGBA_8888_GrPixelConfig, nullptr, randNumSamples,
+                GrMipMapped::kNo, kBottomLeft_GrSurfaceOrigin);
+        randNumSamples = pick_random_sample_count(patternSize, &rand, ctx->caps());
         topDowns[i] = ctx->makeDeferredRenderTargetContext(
-                          SkBackingFit::kExact, 100, 100, kRGBA_8888_GrPixelConfig, nullptr,
-                          rand.nextRangeU(1 + numSamples / 2, numSamples), GrMipMapped::kNo,
-                          kTopLeft_GrSurfaceOrigin);
+                SkBackingFit::kExact, 100, 100, kRGBA_8888_GrPixelConfig, nullptr, randNumSamples,
+                GrMipMapped::kNo, kTopLeft_GrSurfaceOrigin);
     }
 
     // Ensure all sample locations get queried and/or cached properly.
diff --git a/tests/GrSurfaceTest.cpp b/tests/GrSurfaceTest.cpp
index 3e246ccd93..29f4f25695 100644
--- a/tests/GrSurfaceTest.cpp
+++ b/tests/GrSurfaceTest.cpp
@@ -33,7 +33,7 @@ DEF_GPUTEST_FOR_NULLGL_CONTEXT(GrSurface, reporter, ctxInfo) {
     desc.fWidth = 256;
     desc.fHeight = 256;
     desc.fConfig = kRGBA_8888_GrPixelConfig;
-    desc.fSampleCnt = 0;
+    desc.fSampleCnt = 1;
     sk_sp<GrSurface> texRT1 = resourceProvider->createTexture(desc, SkBudgeted::kNo);
 
     REPORTER_ASSERT(reporter, texRT1.get() == texRT1->asRenderTarget());
@@ -55,8 +55,8 @@ DEF_GPUTEST_FOR_NULLGL_CONTEXT(GrSurface, reporter, ctxInfo) {
     GrBackendTexture backendTex = gpu->createTestingOnlyBackendTexture(
         nullptr, 256, 256, kRGBA_8888_GrPixelConfig, false, GrMipMapped::kNo);
 
-    sk_sp<GrSurface> texRT2 = resourceProvider->wrapRenderableBackendTexture(
-                                                    backendTex, 0, kBorrow_GrWrapOwnership);
+    sk_sp<GrSurface> texRT2 =
+            resourceProvider->wrapRenderableBackendTexture(backendTex, 1, kBorrow_GrWrapOwnership);
 
     REPORTER_ASSERT(reporter, texRT2.get() == texRT2->asRenderTarget());
     REPORTER_ASSERT(reporter, texRT2.get() == texRT2->asTexture());
@@ -120,7 +120,7 @@ DEF_GPUTEST_FOR_ALL_CONTEXTS(GrSurfaceRenderability, reporter, ctxInfo) {
             desc.fFlags = kNone_GrSurfaceFlags;
             desc.fOrigin = origin;
             desc.fConfig = config;
-            desc.fSampleCnt = 0;
+            desc.fSampleCnt = 1;
 
             sk_sp<GrSurface> tex = resourceProvider->createTexture(desc, SkBudgeted::kNo);
             bool ict = caps->isConfigTexturable(desc.fConfig);
@@ -148,7 +148,7 @@ DEF_GPUTEST_FOR_ALL_CONTEXTS(GrSurfaceRenderability, reporter, ctxInfo) {
                             "config:%d, tex:%d, isConfigRenderable(false):%d", config,
                             SkToBool(tex), icr);
 
-            desc.fSampleCnt = 4;
+            desc.fSampleCnt = 2;
             tex = resourceProvider->createTexture(desc, SkBudgeted::kNo);
             icr = caps->isConfigRenderable(config, true);
             REPORTER_ASSERT(reporter, SkToBool(tex) == icr,
diff --git a/tests/PathRendererCacheTests.cpp b/tests/PathRendererCacheTests.cpp
index 15b1faa4ba..19197b0d5f 100644
--- a/tests/PathRendererCacheTests.cpp
+++ b/tests/PathRendererCacheTests.cpp
@@ -80,8 +80,8 @@ static void test_path(skiatest::Reporter* reporter,
     GrResourceCache* cache = ctx->contextPriv().getResourceCache();
 
     sk_sp<GrRenderTargetContext> rtc(ctx->makeDeferredRenderTargetContext(
-            SkBackingFit::kApprox, 800, 800, kRGBA_8888_GrPixelConfig, nullptr, 0,
-            GrMipMapped::kNo, kTopLeft_GrSurfaceOrigin));
+            SkBackingFit::kApprox, 800, 800, kRGBA_8888_GrPixelConfig, nullptr, 1, GrMipMapped::kNo,
+            kTopLeft_GrSurfaceOrigin));
     if (!rtc) {
         return;
     }
diff --git a/tests/ProxyTest.cpp b/tests/ProxyTest.cpp
index 0636ed4ce4..3bde3de7ca 100644
--- a/tests/ProxyTest.cpp
+++ b/tests/ProxyTest.cpp
@@ -118,7 +118,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(DeferredProxyTest, reporter, ctxInfo) {
                                  kRGBA_8888_GrPixelConfig }) {
                 for (auto fit : { SkBackingFit::kExact, SkBackingFit::kApprox }) {
                     for (auto budgeted : { SkBudgeted::kYes, SkBudgeted::kNo }) {
-                        for (auto numSamples : { 0, 4, 16, 128 }) {
+                        for (auto numSamples : {1, 4, 16, 128}) {
                             GrSurfaceDesc desc;
                             desc.fFlags = kRenderTarget_GrSurfaceFlag;
                             desc.fOrigin = origin;
@@ -204,10 +204,10 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(WrappedProxyTest, reporter, ctxInfo) {
     for (auto origin : { kBottomLeft_GrSurfaceOrigin, kTopLeft_GrSurfaceOrigin }) {
         for (auto config : { kAlpha_8_GrPixelConfig, kRGBA_8888_GrPixelConfig }) {
             for (auto budgeted : { SkBudgeted::kYes, SkBudgeted::kNo }) {
-                for (auto numSamples: { 0, 4}) {
+                for (auto numSamples : {1, 4}) {
                     int supportedNumSamples = caps.getSampleCount(numSamples, config);
 
-                    bool renderable = caps.isConfigRenderable(config, numSamples > 0);
+                    bool renderable = caps.isConfigRenderable(config, numSamples > 1);
 
                     GrSurfaceDesc desc;
                     desc.fOrigin = origin;
@@ -251,7 +251,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(WrappedProxyTest, reporter, ctxInfo) {
                     } else {
                         // Internal offscreen texture
                         SkASSERT(kNone_GrSurfaceFlags == desc.fFlags );
-                        desc.fSampleCnt = 0;
+                        desc.fSampleCnt = 1;
 
                         sk_sp<GrSurfaceProxy> sProxy = proxyProvider->createInstantiatedProxy(
                                                           desc, SkBackingFit::kExact, budgeted);
@@ -287,7 +287,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(ZeroSizedProxyTest, reporter, ctxInfo) {
                     desc.fWidth = width;
                     desc.fHeight = height;
                     desc.fConfig = kRGBA_8888_GrPixelConfig;
-                    desc.fSampleCnt = 0;
+                    desc.fSampleCnt = 1;
 
                     sk_sp<GrTextureProxy> proxy = provider->createProxy(desc, fit, SkBudgeted::kNo);
                     REPORTER_ASSERT(reporter, !proxy);
diff --git a/tests/ResourceCacheTest.cpp b/tests/ResourceCacheTest.cpp
index 34ed4f7328..da2e278367 100644
--- a/tests/ResourceCacheTest.cpp
+++ b/tests/ResourceCacheTest.cpp
@@ -129,21 +129,20 @@ DEF_GPUTEST_FOR_CONTEXTS(ResourceCacheStencilBuffers, &is_rendering_and_not_angl
 
     GrResourceProvider* resourceProvider = context->contextPriv().resourceProvider();
 
-    sk_sp<GrRenderTarget> smallRT0 = create_RT_with_SB(resourceProvider, 4, 0, SkBudgeted::kYes);
+    sk_sp<GrRenderTarget> smallRT0 = create_RT_with_SB(resourceProvider, 4, 1, SkBudgeted::kYes);
     REPORTER_ASSERT(reporter, smallRT0);
 
     {
        // Two budgeted RTs with the same desc should share a stencil buffer.
-        sk_sp<GrRenderTarget> smallRT1 = create_RT_with_SB(resourceProvider, 4, 0,
-                                                           SkBudgeted::kYes);
-        REPORTER_ASSERT(reporter, smallRT1);
+       sk_sp<GrRenderTarget> smallRT1 = create_RT_with_SB(resourceProvider, 4, 1, SkBudgeted::kYes);
+       REPORTER_ASSERT(reporter, smallRT1);
 
-        REPORTER_ASSERT(reporter, get_SB(smallRT0.get()) == get_SB(smallRT1.get()));
+       REPORTER_ASSERT(reporter, get_SB(smallRT0.get()) == get_SB(smallRT1.get()));
     }
 
     {
         // An unbudgeted RT with the same desc should also share.
-        sk_sp<GrRenderTarget> smallRT2 = create_RT_with_SB(resourceProvider, 4, 0, SkBudgeted::kNo);
+        sk_sp<GrRenderTarget> smallRT2 = create_RT_with_SB(resourceProvider, 4, 1, SkBudgeted::kNo);
         REPORTER_ASSERT(reporter, smallRT2);
 
         REPORTER_ASSERT(reporter, get_SB(smallRT0.get()) == get_SB(smallRT2.get()));
@@ -151,14 +150,14 @@ DEF_GPUTEST_FOR_CONTEXTS(ResourceCacheStencilBuffers, &is_rendering_and_not_angl
 
     {
         // An RT with a much larger size should not share.
-        sk_sp<GrRenderTarget> bigRT = create_RT_with_SB(resourceProvider, 400, 0, SkBudgeted::kNo);
+        sk_sp<GrRenderTarget> bigRT = create_RT_with_SB(resourceProvider, 400, 1, SkBudgeted::kNo);
         REPORTER_ASSERT(reporter, bigRT);
 
         REPORTER_ASSERT(reporter, get_SB(smallRT0.get()) != get_SB(bigRT.get()));
     }
 
-    int smallSampleCount = context->caps()->getSampleCount(4, kRGBA_8888_GrPixelConfig);
-    if (smallSampleCount > 0) {
+    int smallSampleCount = context->caps()->getSampleCount(2, kRGBA_8888_GrPixelConfig);
+    if (smallSampleCount > 1) {
         // An RT with a different sample count should not share.
         sk_sp<GrRenderTarget> smallMSAART0 = create_RT_with_SB(resourceProvider, 4,
                                                                smallSampleCount, SkBudgeted::kNo);
@@ -183,10 +182,10 @@ DEF_GPUTEST_FOR_CONTEXTS(ResourceCacheStencilBuffers, &is_rendering_and_not_angl
             REPORTER_ASSERT(reporter, get_SB(smallMSAART0.get()) == get_SB(smallMSAART1.get()));
         }
 
-        // But not one with a larger sample count should not. (Also check that the request for 4
-        // samples didn't get rounded up to >= 8 or else they could share.).
-        int bigSampleCount = context->caps()->getSampleCount(8, kRGBA_8888_GrPixelConfig);
-        if (bigSampleCount != smallSampleCount) {
+        // But one with a larger sample count should not. (Also check that the two requests didn't
+        // rounded up to the same actual sample count or else they could share.).
+        int bigSampleCount = context->caps()->getSampleCount(5, kRGBA_8888_GrPixelConfig);
+        if (bigSampleCount > 0 && bigSampleCount != smallSampleCount) {
             sk_sp<GrRenderTarget> smallMSAART2 = create_RT_with_SB(resourceProvider, 4,
                                                                    bigSampleCount,
                                                                    SkBudgeted::kNo);
@@ -1707,7 +1706,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(GPUMemorySize, reporter, ctxInfo) {
     {
         sk_sp<GrTexture> tex;
 
-        tex = make_normal_texture(resourceProvider, kRenderTarget_GrSurfaceFlag, kSize, kSize, 0);
+        tex = make_normal_texture(resourceProvider, kRenderTarget_GrSurfaceFlag, kSize, kSize, 1);
         size_t size = tex->gpuMemorySize();
         REPORTER_ASSERT(reporter, kSize*kSize*4 == size);
 
@@ -1722,7 +1721,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(GPUMemorySize, reporter, ctxInfo) {
                             kSize*kSize*4*(sampleCount+1) == size);   // explicit resolve buffer
         }
 
-        tex = make_normal_texture(resourceProvider, kNone_GrSurfaceFlags, kSize, kSize, 0);
+        tex = make_normal_texture(resourceProvider, kNone_GrSurfaceFlags, kSize, kSize, 1);
         size = tex->gpuMemorySize();
         REPORTER_ASSERT(reporter, kSize*kSize*4 == size);
     }
@@ -1732,7 +1731,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(GPUMemorySize, reporter, ctxInfo) {
     if (context->caps()->mipMapSupport()) {
         sk_sp<GrTextureProxy> proxy;
 
-        proxy = make_mipmap_proxy(proxyProvider, kRenderTarget_GrSurfaceFlag, kSize, kSize, 0);
+        proxy = make_mipmap_proxy(proxyProvider, kRenderTarget_GrSurfaceFlag, kSize, kSize, 1);
         size_t size = proxy->gpuMemorySize();
         REPORTER_ASSERT(reporter, kSize*kSize*4+(kSize*kSize*4)/3 == size);
 
@@ -1747,7 +1746,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(GPUMemorySize, reporter, ctxInfo) {
                kSize*kSize*4*(sampleCount+1)+(kSize*kSize*4)/3 == size);  // explicit resolve buffer
         }
 
-        proxy = make_mipmap_proxy(proxyProvider, kNone_GrSurfaceFlags, kSize, kSize, 0);
+        proxy = make_mipmap_proxy(proxyProvider, kNone_GrSurfaceFlags, kSize, kSize, 1);
         size = proxy->gpuMemorySize();
         REPORTER_ASSERT(reporter, kSize*kSize*4+(kSize*kSize*4)/3 == size);
     }
diff --git a/tests/SkpSkGrTest.cpp b/tests/SkpSkGrTest.cpp
index 24d1b9cc3a..898faf08a7 100644
--- a/tests/SkpSkGrTest.cpp
+++ b/tests/SkpSkGrTest.cpp
@@ -442,7 +442,7 @@ void TestResult::testOne() {
         desc.fFlags = kRenderTarget_GrTextureFlagBit;
         desc.fWidth = dim.fX;
         desc.fHeight = dim.fY;
-        desc.fSampleCnt = 0;
+        desc.fSampleCnt = 1;
         sk_sp<GrTexture> texture(context->createUncachedTexture(desc, nullptr, 0));
         if (!texture) {
             SkDebugf("unable to allocate texture for %s (w=%d h=%d)\n", fFilename,
diff --git a/tests/SurfaceTest.cpp b/tests/SurfaceTest.cpp
index 471953b373..af73473fad 100644
--- a/tests/SurfaceTest.cpp
+++ b/tests/SurfaceTest.cpp
@@ -704,7 +704,7 @@ DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(SurfaceClear_Gpu, reporter, ctxInfo) {
         for (auto& surfaceFunc : {&create_gpu_surface_backend_texture,
                                   &create_gpu_surface_backend_texture_as_render_target}) {
             GrBackendTexture backendTex;
-            auto surface = surfaceFunc(context, 0, kOrigColor, &backendTex);
+            auto surface = surfaceFunc(context, 1, kOrigColor, &backendTex);
             test_surface_clear(reporter, surface, grSurfaceGetter, kOrigColor);
             surface.reset();
             gpu->deleteTestingOnlyBackendTexture(&backendTex);
@@ -767,7 +767,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(SurfacePartialDraw_Gpu, reporter, ctxInfo) {
         // preserved in pixels that aren't rendered to via the surface.
         // This works only for non-multisampled case.
         GrBackendTexture backendTex;
-        auto surface = surfaceFunc(ctxInfo.grContext(), 0, kOrigColor, &backendTex);
+        auto surface = surfaceFunc(ctxInfo.grContext(), 1, kOrigColor, &backendTex);
         if (surface) {
             test_surface_draw_partially(reporter, surface, kOrigColor);
             surface.reset();
@@ -791,11 +791,11 @@ DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(SurfaceAttachStencil_Gpu, reporter, ctxInf
 
     for (auto& surfaceFunc : {&create_gpu_surface_backend_texture,
                               &create_gpu_surface_backend_texture_as_render_target}) {
-        for (int sampleCnt : {0, 4, 8}) {
+        for (int sampleCnt : {1, 4, 8}) {
             GrBackendTexture backendTex;
             auto surface = surfaceFunc(ctxInfo.grContext(), sampleCnt, kOrigColor, &backendTex);
 
-            if (!surface && sampleCnt > 0) {
+            if (!surface && sampleCnt > 1) {
                 // Certain platforms don't support MSAA, skip these.
                 continue;
             }
diff --git a/tests/TessellatingPathRendererTests.cpp b/tests/TessellatingPathRendererTests.cpp
index 1eb055f53a..e24bf7a516 100644
--- a/tests/TessellatingPathRendererTests.cpp
+++ b/tests/TessellatingPathRendererTests.cpp
@@ -486,13 +486,8 @@ static void test_path(GrContext* ctx,
 DEF_GPUTEST_FOR_ALL_CONTEXTS(TessellatingPathRendererTests, reporter, ctxInfo) {
     GrContext* ctx = ctxInfo.grContext();
     sk_sp<GrRenderTargetContext> rtc(ctx->makeDeferredRenderTargetContext(
-                                                                  SkBackingFit::kApprox,
-                                                                  800, 800,
-                                                                  kRGBA_8888_GrPixelConfig,
-                                                                  nullptr,
-                                                                  0,
-                                                                  GrMipMapped::kNo,
-                                                                  kTopLeft_GrSurfaceOrigin));
+            SkBackingFit::kApprox, 800, 800, kRGBA_8888_GrPixelConfig, nullptr, 1, GrMipMapped::kNo,
+            kTopLeft_GrSurfaceOrigin));
     if (!rtc) {
         return;
     }
diff --git a/tests/TextureProxyTest.cpp b/tests/TextureProxyTest.cpp
index d422b076ad..059113033a 100644
--- a/tests/TextureProxyTest.cpp
+++ b/tests/TextureProxyTest.cpp
@@ -34,7 +34,7 @@ static GrSurfaceDesc make_desc(GrSurfaceFlags flags) {
     desc.fWidth = 64;
     desc.fHeight = 64;
     desc.fConfig = kRGBA_8888_GrPixelConfig;
-    desc.fSampleCnt = 0;
+    desc.fSampleCnt = 1;
 
     return desc;
 }
diff --git a/tests/TransferPixelsTest.cpp b/tests/TransferPixelsTest.cpp
index ce8d1edc4f..8f71528da6 100755
--- a/tests/TransferPixelsTest.cpp
+++ b/tests/TransferPixelsTest.cpp
@@ -104,7 +104,7 @@ void basic_transfer_test(skiatest::Reporter* reporter, GrContext* context, GrPix
     desc.fWidth = kTextureWidth;
     desc.fHeight = kTextureHeight;
     desc.fConfig = config;
-    desc.fSampleCnt = 0;
+    desc.fSampleCnt = 1;
     sk_sp<GrTexture> tex = resourceProvider->createTexture(desc, SkBudgeted::kNo);
 
     //////////////////////////
diff --git a/tests/VkClearTests.cpp b/tests/VkClearTests.cpp
index c797ef2c33..0dcb446ee5 100644
--- a/tests/VkClearTests.cpp
+++ b/tests/VkClearTests.cpp
@@ -58,7 +58,7 @@ void basic_clear_test(skiatest::Reporter* reporter, GrContext* context, GrPixelC
     surfDesc.fWidth = 5;
     surfDesc.fHeight = 5;
     surfDesc.fConfig = config;
-    surfDesc.fSampleCnt = 0;
+    surfDesc.fSampleCnt = 1;
     GrTexture* tex = gpu->createTexture(surfDesc, SkBudgeted::kNo);
     SkASSERT(tex);
     SkASSERT(tex->asRenderTarget());
@@ -114,7 +114,7 @@ void sub_clear_test(skiatest::Reporter* reporter, GrContext* context, GrPixelCon
     surfDesc.fWidth = width;
     surfDesc.fHeight = height;
     surfDesc.fConfig = config;
-    surfDesc.fSampleCnt = 0;
+    surfDesc.fSampleCnt = 1;
     GrTexture* tex = gpu->createTexture(surfDesc, SkBudgeted::kNo);
     SkASSERT(tex);
     SkASSERT(tex->asRenderTarget());
diff --git a/tests/VkUploadPixelsTests.cpp b/tests/VkUploadPixelsTests.cpp
index 3b3fecae7f..f35480a6ce 100644
--- a/tests/VkUploadPixelsTests.cpp
+++ b/tests/VkUploadPixelsTests.cpp
@@ -69,7 +69,7 @@ void basic_texture_test(skiatest::Reporter* reporter, GrContext* context, GrPixe
     surfDesc.fWidth = kWidth;
     surfDesc.fHeight = kHeight;
     surfDesc.fConfig = config;
-    surfDesc.fSampleCnt = 0;
+    surfDesc.fSampleCnt = 1;
 
     SkColorType ct;
     SkAssertResult(GrPixelConfigToColorType(config, &ct));
diff --git a/tests/VkWrapTests.cpp b/tests/VkWrapTests.cpp
index 6cfbba65b6..9723d5763b 100644
--- a/tests/VkWrapTests.cpp
+++ b/tests/VkWrapTests.cpp
@@ -83,7 +83,7 @@ void wrap_rt_test(skiatest::Reporter* reporter, GrContext* context) {
                                                                            GrMipMapped::kNo);
     const GrVkImageInfo* imageInfo = origBackendTex.getVkImageInfo();
 
-    GrBackendRenderTarget origBackendRT(kW, kH, 0, 0, *imageInfo);
+    GrBackendRenderTarget origBackendRT(kW, kH, 1, 0, *imageInfo);
 
     sk_sp<GrRenderTarget> rt = gpu->wrapBackendRenderTarget(origBackendRT);
     REPORTER_ASSERT(reporter, rt);
@@ -92,7 +92,7 @@ void wrap_rt_test(skiatest::Reporter* reporter, GrContext* context) {
     {
         GrVkImageInfo backendCopy = *imageInfo;
         backendCopy.fImage = VK_NULL_HANDLE;
-        GrBackendRenderTarget backendRT(kW, kH, 0, 0, backendCopy);
+        GrBackendRenderTarget backendRT(kW, kH, 1, 0, backendCopy);
         rt = gpu->wrapBackendRenderTarget(backendRT);
         REPORTER_ASSERT(reporter, !rt);
     }
@@ -102,7 +102,7 @@ void wrap_rt_test(skiatest::Reporter* reporter, GrContext* context) {
         GrVkImageInfo backendCopy = *imageInfo;
         backendCopy.fAlloc = { VK_NULL_HANDLE, 0, 0, 0 };
         // can wrap null alloc
-        GrBackendRenderTarget backendRT(kW, kH, 0, 0, backendCopy);
+        GrBackendRenderTarget backendRT(kW, kH, 1, 0, backendCopy);
         rt = gpu->wrapBackendRenderTarget(backendRT);
         REPORTER_ASSERT(reporter, rt);
     }
@@ -120,8 +120,8 @@ void wrap_trt_test(skiatest::Reporter* reporter, GrContext* context) {
                                                                            GrMipMapped::kNo);
     const GrVkImageInfo* imageInfo = origBackendTex.getVkImageInfo();
 
-    sk_sp<GrTexture> tex = gpu->wrapRenderableBackendTexture(origBackendTex, 0,
-                                                             kBorrow_GrWrapOwnership);
+    sk_sp<GrTexture> tex =
+            gpu->wrapRenderableBackendTexture(origBackendTex, 1, kBorrow_GrWrapOwnership);
     REPORTER_ASSERT(reporter, tex);
 
     // image is null
@@ -129,9 +129,9 @@ void wrap_trt_test(skiatest::Reporter* reporter, GrContext* context) {
         GrVkImageInfo backendCopy = *imageInfo;
         backendCopy.fImage = VK_NULL_HANDLE;
         GrBackendTexture backendTex = GrBackendTexture(kW, kH, backendCopy);
-        tex = gpu->wrapRenderableBackendTexture(backendTex, 0, kBorrow_GrWrapOwnership);
+        tex = gpu->wrapRenderableBackendTexture(backendTex, 1, kBorrow_GrWrapOwnership);
         REPORTER_ASSERT(reporter, !tex);
-        tex = gpu->wrapRenderableBackendTexture(backendTex, 0, kAdopt_GrWrapOwnership);
+        tex = gpu->wrapRenderableBackendTexture(backendTex, 1, kAdopt_GrWrapOwnership);
         REPORTER_ASSERT(reporter, !tex);
     }
 
@@ -140,9 +140,9 @@ void wrap_trt_test(skiatest::Reporter* reporter, GrContext* context) {
         GrVkImageInfo backendCopy = *imageInfo;
         backendCopy.fAlloc = { VK_NULL_HANDLE, 0, 0, 0 };
         GrBackendTexture backendTex = GrBackendTexture(kW, kH, backendCopy);
-        tex = gpu->wrapRenderableBackendTexture(backendTex, 0, kBorrow_GrWrapOwnership);
+        tex = gpu->wrapRenderableBackendTexture(backendTex, 1, kBorrow_GrWrapOwnership);
         REPORTER_ASSERT(reporter, !tex);
-        tex = gpu->wrapRenderableBackendTexture(backendTex, 0, kAdopt_GrWrapOwnership);
+        tex = gpu->wrapRenderableBackendTexture(backendTex, 1, kAdopt_GrWrapOwnership);
         REPORTER_ASSERT(reporter, !tex);
     }
 
@@ -150,7 +150,7 @@ void wrap_trt_test(skiatest::Reporter* reporter, GrContext* context) {
     {
         GrVkImageInfo backendCopy = *imageInfo;
         GrBackendTexture backendTex = GrBackendTexture(kW, kH, backendCopy);
-        tex = gpu->wrapRenderableBackendTexture(backendTex, 0, kAdopt_GrWrapOwnership);
+        tex = gpu->wrapRenderableBackendTexture(backendTex, 1, kAdopt_GrWrapOwnership);
         REPORTER_ASSERT(reporter, tex);
     }
 
diff --git a/tests/WritePixelsTest.cpp b/tests/WritePixelsTest.cpp
index a16752f229..2a2ee397ef 100644
--- a/tests/WritePixelsTest.cpp
+++ b/tests/WritePixelsTest.cpp
@@ -412,11 +412,11 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(WritePixels_Gpu, reporter, ctxInfo) {
     const SkImageInfo ii = SkImageInfo::MakeN32Premul(DEV_W, DEV_H);
 
     for (auto& origin : { kTopLeft_GrSurfaceOrigin, kBottomLeft_GrSurfaceOrigin }) {
-        for (int sampleCnt : {0, 4}) {
+        for (int sampleCnt : {1, 4}) {
             sk_sp<SkSurface> surface(SkSurface::MakeRenderTarget(ctxInfo.grContext(),
                                                                  SkBudgeted::kNo, ii, sampleCnt,
                                                                  origin, nullptr));
-            if (!surface && sampleCnt > 0) {
+            if (!surface && sampleCnt > 1) {
                 // Some platforms don't support MSAA
                 continue;
             }
@@ -430,7 +430,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(WritePixelsNonTexture_Gpu, reporter, ctxInfo)
     GrGpu* gpu = context->contextPriv().getGpu();
 
     for (auto& origin : { kTopLeft_GrSurfaceOrigin, kBottomLeft_GrSurfaceOrigin }) {
-        for (int sampleCnt : {0, 4}) {
+        for (int sampleCnt : {1, 4}) {
             GrBackendTexture backendTex = gpu->createTestingOnlyBackendTexture(
                     nullptr, DEV_W, DEV_H, kSkia8888_GrPixelConfig, true, GrMipMapped::kNo);
             SkColorType colorType;
diff --git a/tools/fiddle/fiddle_main.cpp b/tools/fiddle/fiddle_main.cpp
index 4ba84f38ca..684bc2ae48 100644
--- a/tools/fiddle/fiddle_main.cpp
+++ b/tools/fiddle/fiddle_main.cpp
@@ -133,7 +133,7 @@ static bool setup_backend_objects(GrContext* context,
     backingDesc.fHeight = bm.height();
     // This config must match the SkColorType used in draw.cpp in the SkImage and Surface factories
     backingDesc.fConfig = kRGBA_8888_GrPixelConfig;
-    backingDesc.fSampleCnt = 0;
+    backingDesc.fSampleCnt = 1;
 
     if (!bm.empty()) {
         SkPixmap originalPixmap;
diff --git a/tools/sk_app/DisplayParams.h b/tools/sk_app/DisplayParams.h
index 959735e8ff..203e8bdeca 100644
--- a/tools/sk_app/DisplayParams.h
+++ b/tools/sk_app/DisplayParams.h
@@ -13,10 +13,7 @@
 namespace sk_app {
 
 struct DisplayParams {
-    DisplayParams()
-        : fColorType(kN32_SkColorType)
-        , fColorSpace(nullptr)
-        , fMSAASampleCount(0) {}
+    DisplayParams() : fColorType(kN32_SkColorType), fColorSpace(nullptr), fMSAASampleCount(1) {}
 
     SkColorType         fColorType;
     sk_sp<SkColorSpace> fColorSpace;
diff --git a/tools/sk_app/GLWindowContext.cpp b/tools/sk_app/GLWindowContext.cpp
index 9ef5141fee..9d042cf19e 100644
--- a/tools/sk_app/GLWindowContext.cpp
+++ b/tools/sk_app/GLWindowContext.cpp
@@ -24,9 +24,7 @@ GLWindowContext::GLWindowContext(const DisplayParams& params)
     : WindowContext(params)
     , fBackendContext(nullptr)
     , fSurface(nullptr) {
-    fDisplayParams.fMSAASampleCount = fDisplayParams.fMSAASampleCount ?
-                                      GrNextPow2(fDisplayParams.fMSAASampleCount) :
-                                      0;
+    fDisplayParams.fMSAASampleCount = GrNextPow2(fDisplayParams.fMSAASampleCount);
 }
 
 void GLWindowContext::initializeContext() {
@@ -34,7 +32,7 @@ void GLWindowContext::initializeContext() {
 
     fBackendContext = this->onInitializeContext();
     fContext = GrContext::MakeGL(fBackendContext, fDisplayParams.fGrContextOptions);
-    if (!fContext && fDisplayParams.fMSAASampleCount) {
+    if (!fContext && fDisplayParams.fMSAASampleCount > 1) {
         fDisplayParams.fMSAASampleCount /= 2;
         this->initializeContext();
         return;
diff --git a/tools/sk_app/Window.cpp b/tools/sk_app/Window.cpp
index 29e4864ba1..1694beaac8 100644
--- a/tools/sk_app/Window.cpp
+++ b/tools/sk_app/Window.cpp
@@ -117,7 +117,7 @@ void Window::setRequestedDisplayParams(const DisplayParams& params, bool /* allo
 
 int Window::sampleCount() const {
     if (!fWindowContext) {
-        return -1;
+        return 0;
     }
     return fWindowContext->sampleCount();
 }
diff --git a/tools/sk_app/WindowContext.h b/tools/sk_app/WindowContext.h
index 5e7d76d4ba..71c21ac089 100644
--- a/tools/sk_app/WindowContext.h
+++ b/tools/sk_app/WindowContext.h
@@ -21,11 +21,11 @@ namespace sk_app {
 class WindowContext {
 public:
     WindowContext(const DisplayParams& params)
-        : fContext(nullptr)
-        , fDisplayParams(params)
-        , fSurfaceProps(SkSurfaceProps::kLegacyFontHost_InitType)
-        , fSampleCount(0)
-        , fStencilBits(0) {}
+            : fContext(nullptr)
+            , fDisplayParams(params)
+            , fSurfaceProps(SkSurfaceProps::kLegacyFontHost_InitType)
+            , fSampleCount(1)
+            , fStencilBits(0) {}
 
     virtual ~WindowContext() {}
 
diff --git a/tools/sk_app/android/GLWindowContext_android.cpp b/tools/sk_app/android/GLWindowContext_android.cpp
index acdb587230..5111114115 100644
--- a/tools/sk_app/android/GLWindowContext_android.cpp
+++ b/tools/sk_app/android/GLWindowContext_android.cpp
@@ -70,6 +70,8 @@ sk_sp<const GrGLInterface> GLWindowContext_android::onInitializeContext() {
     SkAssertResult(eglBindAPI(EGL_OPENGL_ES_API));
 
     EGLint numConfigs = 0;
+    EGLint eglSampleCnt = fDisplayParams.fMSAASampleCount > 1 ? fDisplayParams.fMSAASampleCount > 1
+                                                              : 0;
     const EGLint configAttribs[] = {
         EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
         EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
@@ -78,8 +80,8 @@ sk_sp<const GrGLInterface> GLWindowContext_android::onInitializeContext() {
         EGL_BLUE_SIZE, 8,
         EGL_ALPHA_SIZE, 8,
         EGL_STENCIL_SIZE, 8,
-        EGL_SAMPLE_BUFFERS, fDisplayParams.fMSAASampleCount ? 1 : 0,
-        EGL_SAMPLES, fDisplayParams.fMSAASampleCount,
+        EGL_SAMPLE_BUFFERS, eglSampleCnt ? 1 : 0,
+        EGL_SAMPLES, eglSampleCnt,
         EGL_NONE
     };
 
@@ -131,6 +133,7 @@ sk_sp<const GrGLInterface> GLWindowContext_android::onInitializeContext() {
 
     eglGetConfigAttrib(fDisplay, surfaceConfig, EGL_STENCIL_SIZE, &fStencilBits);
     eglGetConfigAttrib(fDisplay, surfaceConfig, EGL_SAMPLES, &fSampleCount);
+    fSampleCount = SkTMax(fSampleCount, 1);
 
     return GrGLMakeNativeInterface();
 }
diff --git a/tools/sk_app/ios/GLWindowContext_ios.cpp b/tools/sk_app/ios/GLWindowContext_ios.cpp
index f4c0d6b3c0..2a57b33e30 100644
--- a/tools/sk_app/ios/GLWindowContext_ios.cpp
+++ b/tools/sk_app/ios/GLWindowContext_ios.cpp
@@ -67,6 +67,7 @@ sk_sp<const GrGLInterface> GLWindowContext_ios::onInitializeContext() {
 
         SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, &fStencilBits);
         SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &fSampleCount);
+        fSampleCount = SkTMax(fSampleCount, 1);
 
         SDL_GL_GetDrawableSize(fWindow, &fWidth, &fHeight);
         glViewport(0, 0, fWidth, fHeight);
diff --git a/tools/sk_app/ios/RasterWindowContext_ios.cpp b/tools/sk_app/ios/RasterWindowContext_ios.cpp
index cae5774c28..53d7c1a372 100644
--- a/tools/sk_app/ios/RasterWindowContext_ios.cpp
+++ b/tools/sk_app/ios/RasterWindowContext_ios.cpp
@@ -79,6 +79,7 @@ sk_sp<const GrGLInterface> RasterWindowContext_ios::onInitializeContext() {
 
         SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, &fStencilBits);
         SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &fSampleCount);
+        fSampleCount = SkTMax(fSampleCount, 1);
 
         SDL_GL_GetDrawableSize(fWindow, &fWidth, &fHeight);
         glViewport(0, 0, fWidth, fHeight);
diff --git a/tools/sk_app/ios/Window_ios.cpp b/tools/sk_app/ios/Window_ios.cpp
index c1bdeae5fc..ac0ad0caa0 100644
--- a/tools/sk_app/ios/Window_ios.cpp
+++ b/tools/sk_app/ios/Window_ios.cpp
@@ -49,7 +49,7 @@ bool Window_ios::initWindow() {
 
     SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, 1);
 
-    if (fRequestedDisplayParams.fMSAASampleCount > 0) {
+    if (fRequestedDisplayParams.fMSAASampleCount > 1) {
         SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
         SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, fRequestedDisplayParams.fMSAASampleCount);
     } else {
diff --git a/tools/sk_app/ios/Window_ios.h b/tools/sk_app/ios/Window_ios.h
index 667fa74e82..a0fed90697 100644
--- a/tools/sk_app/ios/Window_ios.h
+++ b/tools/sk_app/ios/Window_ios.h
@@ -18,11 +18,7 @@ namespace sk_app {
 
 class Window_ios : public Window {
 public:
-    Window_ios()
-        : INHERITED()
-        , fWindow(nullptr)
-        , fWindowID(0)
-        , fMSAASampleCount(0) {}
+    Window_ios() : INHERITED(), fWindow(nullptr), fWindowID(0), fMSAASampleCount(1) {}
     ~Window_ios() override { this->closeWindow(); }
 
     bool initWindow();
diff --git a/tools/sk_app/mac/GLWindowContext_mac.cpp b/tools/sk_app/mac/GLWindowContext_mac.cpp
index 005fc07df4..67fb853fee 100644
--- a/tools/sk_app/mac/GLWindowContext_mac.cpp
+++ b/tools/sk_app/mac/GLWindowContext_mac.cpp
@@ -67,6 +67,7 @@ sk_sp<const GrGLInterface> GLWindowContext_mac::onInitializeContext() {
 
         SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, &fStencilBits);
         SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &fSampleCount);
+        fSampleCount = SkTMax(fSampleCount, 1);
 
         SDL_GetWindowSize(fWindow, &fWidth, &fHeight);
         glViewport(0, 0, fWidth, fHeight);
diff --git a/tools/sk_app/mac/RasterWindowContext_mac.cpp b/tools/sk_app/mac/RasterWindowContext_mac.cpp
index 67022af7fe..fbe9837911 100644
--- a/tools/sk_app/mac/RasterWindowContext_mac.cpp
+++ b/tools/sk_app/mac/RasterWindowContext_mac.cpp
@@ -79,6 +79,7 @@ sk_sp<const GrGLInterface> RasterWindowContext_mac::onInitializeContext() {
 
         SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, &fStencilBits);
         SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &fSampleCount);
+        fSampleCount = SkTMax(fSampleCount, 1);
 
         SDL_GetWindowSize(fWindow, &fWidth, &fHeight);
         glViewport(0, 0, fWidth, fHeight);
diff --git a/tools/sk_app/mac/Window_mac.cpp b/tools/sk_app/mac/Window_mac.cpp
index 8de5b10450..f2620518a2 100644
--- a/tools/sk_app/mac/Window_mac.cpp
+++ b/tools/sk_app/mac/Window_mac.cpp
@@ -49,7 +49,7 @@ bool Window_mac::initWindow() {
 
     SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, 1);
 
-    if (fRequestedDisplayParams.fMSAASampleCount > 0) {
+    if (fRequestedDisplayParams.fMSAASampleCount > 1) {
         SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
         SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, fRequestedDisplayParams.fMSAASampleCount);
     } else {
diff --git a/tools/sk_app/mac/Window_mac.h b/tools/sk_app/mac/Window_mac.h
index aa5c8df696..35cba095fa 100644
--- a/tools/sk_app/mac/Window_mac.h
+++ b/tools/sk_app/mac/Window_mac.h
@@ -18,11 +18,7 @@ namespace sk_app {
 
 class Window_mac : public Window {
 public:
-    Window_mac()
-        : INHERITED()
-        , fWindow(nullptr)
-        , fWindowID(0)
-        , fMSAASampleCount(0) {}
+    Window_mac() : INHERITED(), fWindow(nullptr), fWindowID(0), fMSAASampleCount(1) {}
     ~Window_mac() override { this->closeWindow(); }
 
     bool initWindow();
diff --git a/tools/sk_app/unix/GLWindowContext_unix.cpp b/tools/sk_app/unix/GLWindowContext_unix.cpp
index 25ec95cdd6..3a3a4b16d4 100644
--- a/tools/sk_app/unix/GLWindowContext_unix.cpp
+++ b/tools/sk_app/unix/GLWindowContext_unix.cpp
@@ -99,6 +99,7 @@ sk_sp<const GrGLInterface> GLWindowContext_xlib::onInitializeContext() {
 
     glXGetConfig(fDisplay, fVisualInfo, GLX_STENCIL_SIZE, &fStencilBits);
     glXGetConfig(fDisplay, fVisualInfo, GLX_SAMPLES_ARB, &fSampleCount);
+    fSampleCount = SkTMax(fSampleCount, 1);
 
     XWindow root;
     int x, y;
diff --git a/tools/sk_app/unix/Window_unix.cpp b/tools/sk_app/unix/Window_unix.cpp
index f5ca5ee073..745b4dd3fb 100644
--- a/tools/sk_app/unix/Window_unix.cpp
+++ b/tools/sk_app/unix/Window_unix.cpp
@@ -72,7 +72,7 @@ bool Window_unix::initWindow(Display* display) {
         None
     };
     SkASSERT(nullptr == fVisualInfo);
-    if (fRequestedDisplayParams.fMSAASampleCount > 0) {
+    if (fRequestedDisplayParams.fMSAASampleCount > 1) {
         static const GLint kChooseFBConifgAttCnt = SK_ARRAY_COUNT(kChooseFBConfigAtt);
         GLint msaaChooseFBConfigAtt[kChooseFBConifgAttCnt + 4];
         memcpy(msaaChooseFBConfigAtt, kChooseFBConfigAtt, sizeof(kChooseFBConfigAtt));
diff --git a/tools/sk_app/unix/Window_unix.h b/tools/sk_app/unix/Window_unix.h
index b59f502eb9..62a2795098 100644
--- a/tools/sk_app/unix/Window_unix.h
+++ b/tools/sk_app/unix/Window_unix.h
@@ -20,13 +20,14 @@ namespace sk_app {
 
 class Window_unix : public Window {
 public:
-    Window_unix() : Window()
-                  , fDisplay(nullptr)
-                  , fWindow(0)
-                  , fGC(nullptr)
-                  , fFBConfig(nullptr)
-                  , fVisualInfo(nullptr)
-                  , fMSAASampleCount(0) {}
+    Window_unix()
+            : Window()
+            , fDisplay(nullptr)
+            , fWindow(0)
+            , fGC(nullptr)
+            , fFBConfig(nullptr)
+            , fVisualInfo(nullptr)
+            , fMSAASampleCount(1) {}
     ~Window_unix() override { this->closeWindow(); }
 
     bool initWindow(Display* display);
diff --git a/tools/sk_app/win/ANGLEWindowContext_win.cpp b/tools/sk_app/win/ANGLEWindowContext_win.cpp
index 649528d6cd..452b462ba9 100644
--- a/tools/sk_app/win/ANGLEWindowContext_win.cpp
+++ b/tools/sk_app/win/ANGLEWindowContext_win.cpp
@@ -76,7 +76,8 @@ sk_sp<const GrGLInterface> ANGLEGLWindowContext_win::onInitializeContext() {
     }
     EGLint numConfigs;
     fSampleCount = this->getDisplayParams().fMSAASampleCount;
-    const int sampleBuffers = fSampleCount > 0 ? 1 : 0;
+    const int sampleBuffers = fSampleCount > 1 ? 1 : 0;
+    const int eglSampleCnt = fSampleCount > 1 ? fSampleCount : 0;
     const EGLint configAttribs[] = {EGL_RENDERABLE_TYPE,
                                     // We currently only support ES3.
                                     EGL_OPENGL_ES3_BIT,
@@ -91,7 +92,7 @@ sk_sp<const GrGLInterface> ANGLEGLWindowContext_win::onInitializeContext() {
                                     EGL_SAMPLE_BUFFERS,
                                     sampleBuffers,
                                     EGL_SAMPLES,
-                                    fSampleCount,
+                                    eglSampleCnt,
                                     EGL_NONE};
 
     EGLConfig surfaceConfig;
diff --git a/tools/sk_app/win/GLWindowContext_win.cpp b/tools/sk_app/win/GLWindowContext_win.cpp
index 7e43d2b544..1c583cb1ed 100644
--- a/tools/sk_app/win/GLWindowContext_win.cpp
+++ b/tools/sk_app/win/GLWindowContext_win.cpp
@@ -96,8 +96,9 @@ sk_sp<const GrGLInterface> GLWindowContext_win::onInitializeContext() {
                                               1,
                                               &kSampleCountAttr,
                                               &fSampleCount);
+            fSampleCount = SkTMax(fSampleCount, 1);
         } else {
-            fSampleCount = 0;
+            fSampleCount = 1;
         }
 
         RECT rect;
diff --git a/tools/viewer/Viewer.cpp b/tools/viewer/Viewer.cpp
index 198f9baab6..35b0e146f9 100644
--- a/tools/viewer/Viewer.cpp
+++ b/tools/viewer/Viewer.cpp
@@ -78,7 +78,7 @@ static DEFINE_string(jsons, "jsons", "Directory to read (Bodymovin) jsons from."
 
 static DEFINE_string2(backend, b, "sw", "Backend to use. Allowed values are " BACKENDS_STR ".");
 
-static DEFINE_int32(msaa, 0, "Number of subpixel samples. 0 for no HW antialiasing.");
+static DEFINE_int32(msaa, 1, "Number of subpixel samples. 0 for no HW antialiasing.");
 
 DECLARE_int32(threads)
 
@@ -501,7 +501,7 @@ void Viewer::updateTitle() {
     if (!fWindow) {
         return;
     }
-    if (fWindow->sampleCount() < 0) {
+    if (fWindow->sampleCount() < 1) {
         return; // Surface hasn't been created yet.
     }
 
@@ -561,7 +561,8 @@ void Viewer::updateTitle() {
 
     title.append(" [");
     title.append(kBackendTypeStrings[fBackendType]);
-    if (int msaa = fWindow->sampleCount()) {
+    int msaa = fWindow->sampleCount();
+    if (msaa > 1) {
         title.appendf(" MSAA: %i", msaa);
     }
     title.append("]");
@@ -994,7 +995,7 @@ void Viewer::drawImGui() {
                 if (ctx) {
                     int sampleCount = fWindow->sampleCount();
                     ImGui::Text("MSAA: "); ImGui::SameLine();
-                    ImGui::RadioButton("0", &sampleCount, 0); ImGui::SameLine();
+                    ImGui::RadioButton("1", &sampleCount, 1); ImGui::SameLine();
                     ImGui::RadioButton("4", &sampleCount, 4); ImGui::SameLine();
                     ImGui::RadioButton("8", &sampleCount, 8); ImGui::SameLine();
                     ImGui::RadioButton("16", &sampleCount, 16);
@@ -1018,7 +1019,7 @@ void Viewer::drawImGui() {
 
                     if (!ctx) {
                         ImGui::RadioButton("Software", true);
-                    } else if (fWindow->sampleCount()) {
+                    } else if (fWindow->sampleCount() > 1) {
                         prButton(GpuPathRenderers::kDefault);
                         prButton(GpuPathRenderers::kAll);
                         if (ctx->caps()->shaderCaps()->pathRenderingSupport()) {
@@ -1198,7 +1199,7 @@ void Viewer::updateUIState() {
     if (!fWindow) {
         return;
     }
-    if (fWindow->sampleCount() < 0) {
+    if (fWindow->sampleCount() < 1) {
         return; // Surface hasn't been created yet.
     }
 
@@ -1244,7 +1245,7 @@ void Viewer::updateUIState() {
     const GrContext* ctx = fWindow->getGrContext();
     if (!ctx) {
         prState[kOptions].append("Software");
-    } else if (fWindow->sampleCount()) {
+    } else if (fWindow->sampleCount() > 1) {
         prState[kOptions].append(gPathRendererNames[GpuPathRenderers::kDefault]);
         prState[kOptions].append(gPathRendererNames[GpuPathRenderers::kAll]);
         if (ctx->caps()->shaderCaps()->pathRenderingSupport()) {
author	Brian Salomon <bsalomon@google.com>	2018-02-01 12:54:30 -0500
committer	Skia Commit-Bot <skia-commit-bot@chromium.org>	2018-02-01 18:16:58 +0000
commit	48825b11ad25c98b9a4884d5cc0edd4e290c4409 (patch)
tree	4278b01107ad8da03453c879ee50ce1a471d2ee2
parent	f8393c861975350c4ca9d4f6c95b186c081dbbcf (diff)