Revert "Revert "Revert "Revert "Redefine the meaning of sample counts in GPU backend.""""

This reverts commit 18c52a7b52211de5d0dcd86dc048adef758c6c75.

Also relands "More sample count cleanup:" and "Add new GrContext queries for imagability, surfacability, and max sample count of color types"


Bug: skia:
Change-Id: I4028105a3a1f16ce3944e134619eb6245af6b947
Reviewed-on: https://skia-review.googlesource.com/102940
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

5 files changed, 73 insertions, 48 deletions

diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 3b90676be1..99f56564d8 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;
         }
     }
 
@@ -2034,7 +2046,7 @@ bool GrGLCaps::initDescForDstCopy(const GrRenderTargetProxy* src, GrSurfaceDesc*
 
     // If the src is a texture, we can implement the blit as a draw assuming the config is
     // renderable.
-    if (src->asTextureProxy() && this->isConfigRenderable(src->config(), false)) {
+    if (src->asTextureProxy() && !this->isConfigRenderable(src->config())) {
         desc->fOrigin = kBottomLeft_GrSurfaceOrigin;
         desc->fFlags = kRenderTarget_GrSurfaceFlag;
         desc->fConfig = src->config();
@@ -2059,14 +2071,14 @@ bool GrGLCaps::initDescForDstCopy(const GrRenderTargetProxy* src, GrSurfaceDesc*
     GrSurfaceOrigin originForBlitFramebuffer = kTopLeft_GrSurfaceOrigin;
     bool rectsMustMatchForBlitFramebuffer = false;
     bool disallowSubrectForBlitFramebuffer = false;
-    if (src->numColorSamples() &&
+    if (src->numColorSamples() > 1 &&
         (this->blitFramebufferSupportFlags() & kResolveMustBeFull_BlitFrambufferFlag)) {
         rectsMustMatchForBlitFramebuffer = true;
         disallowSubrectForBlitFramebuffer = true;
         // Mirroring causes rects to mismatch later, don't allow it.
         originForBlitFramebuffer = src->origin();
-    } else if (src->numColorSamples() && (this->blitFramebufferSupportFlags() &
-                                          kRectsMustMatchForMSAASrc_BlitFramebufferFlag)) {
+    } else if (src->numColorSamples() > 1 && (this->blitFramebufferSupportFlags() &
+                                              kRectsMustMatchForMSAASrc_BlitFramebufferFlag)) {
         rectsMustMatchForBlitFramebuffer = true;
         // Mirroring causes rects to mismatch later, don't allow it.
         originForBlitFramebuffer = src->origin();
@@ -2456,18 +2468,31 @@ void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {
     }
 }
 
-int GrGLCaps::getSampleCount(int requestedCount, GrPixelConfig config) const {
+int GrGLCaps::getRenderTargetSampleCount(int requestedCount, GrPixelConfig config) const {
+    requestedCount = SkTMax(1, requestedCount);
     int count = fConfigTable[config].fColorSampleCounts.count();
-    if (!count || !this->isConfigRenderable(config, true)) {
+    if (!count) {
         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;
+}
+
+int GrGLCaps::maxRenderTargetSampleCount(GrPixelConfig config) const {
+    const auto& table = fConfigTable[config].fColorSampleCounts;
+    if (!table.count()) {
+        return 0;
+    }
+    return table[table.count() - 1];
 }
 
 bool validate_sized_format(GrGLenum format, SkColorType ct, GrPixelConfig* config,
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index fd49a65598..7a443e49b0 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -112,19 +112,12 @@ public:
     GrGLCaps(const GrContextOptions& contextOptions, const GrGLContextInfo& ctxInfo,
              const GrGLInterface* glInterface);
 
-    int getSampleCount(int requestedCount, GrPixelConfig config) const override;
-
     bool isConfigTexturable(GrPixelConfig config) const override {
         return SkToBool(fConfigTable[config].fFlags & ConfigInfo::kTextureable_Flag);
     }
 
-    bool isConfigRenderable(GrPixelConfig config, bool withMSAA) const override {
-        if (withMSAA) {
-            return SkToBool(fConfigTable[config].fFlags & ConfigInfo::kRenderableWithMSAA_Flag);
-        } else {
-            return SkToBool(fConfigTable[config].fFlags & ConfigInfo::kRenderable_Flag);
-        }
-    }
+    int getRenderTargetSampleCount(int requestedCount, GrPixelConfig config) const override;
+    int maxRenderTargetSampleCount(GrPixelConfig config) const override;
 
     bool isConfigCopyable(GrPixelConfig config) const override {
         // In GL we have three ways to be able to copy. CopyTexImage, blit, and draw. CopyTexImage
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index ae31495b06..b4a0341174 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;
@@ -581,7 +581,10 @@ sk_sp<GrTexture> GrGLGpu::onWrapRenderableBackendTexture(const GrBackendTexture&
     surfDesc.fWidth = backendTex.width();
     surfDesc.fHeight = backendTex.height();
     surfDesc.fConfig = backendTex.config();
-    surfDesc.fSampleCnt = this->caps()->getSampleCount(sampleCnt, backendTex.config());
+    surfDesc.fSampleCnt = this->caps()->getRenderTargetSampleCount(sampleCnt, backendTex.config());
+    if (surfDesc.fSampleCnt < 1) {
+        return nullptr;
+    }
 
     GrGLRenderTarget::IDDesc rtIDDesc;
     if (!this->createRenderTargetObjects(surfDesc, idDesc.fInfo, &rtIDDesc)) {
@@ -616,7 +619,8 @@ sk_sp<GrRenderTarget> GrGLGpu::onWrapBackendRenderTarget(const GrBackendRenderTa
     desc.fWidth = backendRT.width();
     desc.fHeight = backendRT.height();
     desc.fConfig = backendRT.config();
-    desc.fSampleCnt = this->caps()->getSampleCount(backendRT.sampleCnt(), backendRT.config());
+    desc.fSampleCnt =
+            this->caps()->getRenderTargetSampleCount(backendRT.sampleCnt(), backendRT.config());
 
     return GrGLRenderTarget::MakeWrapped(this, desc, idDesc, backendRT.stencilBits());
 }
@@ -645,7 +649,7 @@ sk_sp<GrRenderTarget> GrGLGpu::onWrapBackendTextureAsRenderTarget(const GrBacken
     surfDesc.fWidth = tex.width();
     surfDesc.fHeight = tex.height();
     surfDesc.fConfig = tex.config();
-    surfDesc.fSampleCnt = this->caps()->getSampleCount(sampleCnt, tex.config());
+    surfDesc.fSampleCnt = this->caps()->getRenderTargetSampleCount(sampleCnt, tex.config());
 
     GrGLRenderTarget::IDDesc rtIDDesc;
     if (!this->createRenderTargetObjects(surfDesc, texInfo, &rtIDDesc)) {
@@ -686,7 +690,7 @@ 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 +708,7 @@ 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 +1281,13 @@ 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 +1300,7 @@ 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 +1317,7 @@ 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 +1342,7 @@ 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 +1419,7 @@ 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();
     }
@@ -1524,7 +1528,7 @@ void inline get_stencil_rb_sizes(const GrGLInterface* gl,
 
 int GrGLGpu::getCompatibleStencilIndex(GrPixelConfig config) {
     static const int kSize = 16;
-    SkASSERT(this->caps()->isConfigRenderable(config, false));
+    SkASSERT(this->caps()->isConfigRenderable(config));
     if (!this->glCaps().hasStencilFormatBeenDeterminedForConfig(config)) {
         // Default to unsupported, set this if we find a stencil format that works.
         int firstWorkingStencilFormatIndex = -1;
@@ -1694,7 +1698,7 @@ 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,
@@ -2133,7 +2137,7 @@ bool GrGLGpu::readPixelsSupported(GrPixelConfig rtConfig, GrPixelConfig readConf
         GrSurfaceDesc desc;
         desc.fConfig = rtConfig;
         desc.fWidth = desc.fHeight = 16;
-        if (this->glCaps().isConfigRenderable(rtConfig, false)) {
+        if (this->glCaps().isConfigRenderable(rtConfig)) {
             desc.fFlags = kRenderTarget_GrSurfaceFlag;
             desc.fOrigin = kBottomLeft_GrSurfaceOrigin;
             temp = this->createTexture(desc, SkBudgeted::kNo);
@@ -2194,7 +2198,7 @@ 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;
@@ -2872,10 +2876,13 @@ void GrGLGpu::flushHWAAState(GrRenderTarget* rt, bool useHWAA, bool stencilEnabl
                 GL_CALL(Enable(GR_GL_RASTER_MULTISAMPLE));
                 fHWRasterMultisampleEnabled = kYes_TriState;
             }
-            if (rt->numStencilSamples() != fHWNumRasterSamples) {
-                SkASSERT(rt->numStencilSamples() <= this->caps()->maxRasterSamples());
-                GL_CALL(RasterSamples(rt->numStencilSamples(), GR_GL_TRUE));
-                fHWNumRasterSamples = rt->numStencilSamples();
+            int numStencilSamples = rt->numStencilSamples();
+            // convert to GL's understanding of sample counts where 0 means nonMSAA.
+            numStencilSamples = 1 == numStencilSamples ? 0 : numStencilSamples;
+            if (numStencilSamples != fHWNumRasterSamples) {
+                SkASSERT(numStencilSamples <= this->caps()->maxRasterSamples());
+                GL_CALL(RasterSamples(numStencilSamples, GR_GL_TRUE));
+                fHWNumRasterSamples = numStencilSamples;
             }
         } else {
             if (kNo_TriState != fHWRasterMultisampleEnabled) {
@@ -3334,8 +3341,8 @@ 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 +3351,7 @@ 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 +3361,12 @@ 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 +3383,7 @@ 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);
 }