Add a flag to GrSurfaceFlags that requires the texture to be cleared upon creation.

Bug: chromium:656320

Change-Id: I940bfa24540516ab83a2ed52f761b96eb6ad19f1
Reviewed-on: https://skia-review.googlesource.com/17391
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

5 files changed, 66 insertions, 6 deletions

diff --git a/src/gpu/gl/GrGLAssembleInterface.cpp b/src/gpu/gl/GrGLAssembleInterface.cpp
index 7914934eac..7305696567 100644
--- a/src/gpu/gl/GrGLAssembleInterface.cpp
+++ b/src/gpu/gl/GrGLAssembleInterface.cpp
@@ -105,6 +105,10 @@ const GrGLInterface* GrGLAssembleGLInterface(void* ctx, GrGLGetProc get) {
     GET_PROC(Clear);
     GET_PROC(ClearColor);
     GET_PROC(ClearStencil);
+    if (glVer >= GR_GL_VER(4,4) || extensions.has("GL_ARB_clear_texture")) {
+        GET_PROC(ClearTexImage);
+        GET_PROC(ClearTexSubImage);
+    }
     GET_PROC(ColorMask);
     GET_PROC(CompileShader);
     GET_PROC(CompressedTexImage2D);
@@ -584,6 +588,10 @@ const GrGLInterface* GrGLAssembleGLESInterface(void* ctx, GrGLGetProc get) {
     GET_PROC(Clear);
     GET_PROC(ClearColor);
     GET_PROC(ClearStencil);
+    if (extensions.has("GL_EXT_clear_texture")) {
+        GET_PROC_SUFFIX(ClearTexImage, EXT);
+        GET_PROC_SUFFIX(ClearTexSubImage, EXT);
+    }
     GET_PROC(ColorMask);
     GET_PROC(CompileShader);
     GET_PROC(CompressedTexImage2D);
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index b9eee088e0..0d84a72121 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -54,6 +54,7 @@ GrGLCaps::GrGLCaps(const GrContextOptions& contextOptions,
     fSRGBDecodeDisableSupport = false;
     fSRGBDecodeDisableAffectsMipmaps = false;
     fClearToBoundaryValuesIsBroken = false;
+    fClearTextureSupport = false;
     fDrawArraysBaseVertexIsBroken = false;
 
     fBlitFramebufferFlags = kNoSupport_BlitFramebufferFlag;
@@ -252,6 +253,14 @@ void GrGLCaps::init(const GrContextOptions& contextOptions,
     // vis-versa.
     fRGBAToBGRAReadbackConversionsAreSlow = isMESA || isMAC;
 
+    if (kGL_GrGLStandard == standard) {
+        if (version >= GR_GL_VER(4,4) || ctxInfo.hasExtension("GL_ARB_clear_texture")) {
+            fClearTextureSupport = true;
+        }
+    } else if (ctxInfo.hasExtension("GL_EXT_clear_texture")) {
+        fClearTextureSupport = true;
+    }
+
     /**************************************************************************
     * GrShaderCaps fields
     **************************************************************************/
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 3059ea7149..b7273a08b1 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -360,6 +360,9 @@ public:
     // Certain Intel GPUs on Mac fail to clear if the glClearColor is made up of only 1s and 0s.
     bool clearToBoundaryValuesIsBroken() const { return fClearToBoundaryValuesIsBroken; }
 
+    /// glClearTex(Sub)Image support
+    bool clearTextureSupport() const { return fClearTextureSupport; }
+
     // Adreno/MSAA drops a draw on the imagefiltersbase GM if the base vertex param to
     // glDrawArrays is nonzero.
     // https://bugs.chromium.org/p/skia/issues/detail?id=6650
@@ -437,6 +440,7 @@ private:
     bool fSRGBDecodeDisableSupport : 1;
     bool fSRGBDecodeDisableAffectsMipmaps : 1;
     bool fClearToBoundaryValuesIsBroken : 1;
+    bool fClearTextureSupport : 1;
     bool fDrawArraysBaseVertexIsBroken : 1;
 
     uint32_t fBlitFramebufferFlags;
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index 565e60a220..81ee87c5e0 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -1320,24 +1320,44 @@ static void set_initial_texture_params(const GrGLInterface* interface,
 
 GrTexture* GrGLGpu::onCreateTexture(const GrSurfaceDesc& desc,
                                     SkBudgeted budgeted,
-                                    const SkTArray<GrMipLevel>& texels) {
+                                    const SkTArray<GrMipLevel>& origTexels) {
     // We fail if the MSAA was requested and is not available.
     if (GrGLCaps::kNone_MSFBOType == this->glCaps().msFBOType() && desc.fSampleCnt) {
         //SkDebugf("MSAA RT requested but not supported on this platform.");
         return return_null_texture();
     }
 
+    bool performClear = (desc.fFlags & kPerformInitialClear_GrSurfaceFlag);
+    const SkTArray<GrMipLevel>* texels = &origTexels;
+
+    SkTArray<GrMipLevel> zeroLevels;
+    std::unique_ptr<uint8_t[]> zeros;
+    // TODO: remove the GrPixelConfigIsSint test. This is here because we have yet to add support
+    // for glClearBuffer* which must be used instead of glClearColor/glClear for integer FBO
+    // attachments.
+    if (performClear && !this->glCaps().clearTextureSupport() &&
+        (!this->glCaps().canConfigBeFBOColorAttachment(desc.fConfig) ||
+         GrPixelConfigIsSint(desc.fConfig))) {
+        size_t rowSize = GrBytesPerPixel(desc.fConfig) * desc.fWidth;
+        size_t size = rowSize * desc.fHeight;
+        zeros.reset(new uint8_t[size]);
+        memset(zeros.get(), 0, size);
+        zeroLevels.push_back(GrMipLevel{zeros.get(), 0});
+        texels = &zeroLevels;
+        performClear = false;
+    }
+
     bool isRenderTarget = SkToBool(desc.fFlags & kRenderTarget_GrSurfaceFlag);
 
     GrGLTexture::IDDesc idDesc;
     idDesc.fOwnership = GrBackendObjectOwnership::kOwned;
     GrGLTexture::TexParams initialTexParams;
-    if (!this->createTextureImpl(desc, &idDesc.fInfo, isRenderTarget, &initialTexParams, texels)) {
+    if (!this->createTextureImpl(desc, &idDesc.fInfo, isRenderTarget, &initialTexParams, *texels)) {
         return return_null_texture();
     }
 
     bool wasMipMapDataProvided = false;
-    if (texels.count() > 1) {
+    if (texels->count() > 1) {
         wasMipMapDataProvided = true;
     }
 
@@ -1361,6 +1381,25 @@ GrTexture* GrGLGpu::onCreateTexture(const GrSurfaceDesc& desc,
     SkDebugf("--- new texture [%d] size=(%d %d) config=%d\n",
              idDesc.fInfo.fID, desc.fWidth, desc.fHeight, desc.fConfig);
 #endif
+    if (tex && performClear) {
+        if (this->glCaps().clearTextureSupport()) {
+            GrGLenum format = GrPixelConfigIsSint(tex->config()) ? GR_GL_RGBA_INTEGER : GR_GL_RGBA;
+            static constexpr uint32_t kZero = 0;
+            GL_CALL(ClearTexImage(tex->textureID(), 0, format, GR_GL_UNSIGNED_BYTE, &kZero));
+        } else {
+            SkASSERT(!GrPixelConfigIsSint(desc.fConfig));
+            GrGLIRect viewport;
+            this->bindSurfaceFBOForPixelOps(tex, GR_GL_FRAMEBUFFER, &viewport, kDst_TempFBOTarget);
+            this->disableScissor();
+            this->disableWindowRectangles();
+            GL_CALL(ColorMask(GR_GL_TRUE, GR_GL_TRUE, GR_GL_TRUE, GR_GL_TRUE));
+            fHWWriteToColor = kYes_TriState;
+            GL_CALL(ClearColor(0, 0, 0, 0));
+            GL_CALL(Clear(GR_GL_COLOR_BUFFER_BIT));
+            this->unbindTextureFBOForPixelOps(GR_GL_FRAMEBUFFER, tex);
+            fHWBoundRenderTargetUniqueID.makeInvalid();
+        }
+    }
     return tex;
 }
 
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index a4706c79ed..d19f2ef6ee 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -371,9 +371,9 @@ private:
         kDst_TempFBOTarget
     };
 
-    // Binds a surface as a FBO for copying or reading. If the surface already owns an FBO ID then
-    // that ID is bound. If not the surface is temporarily bound to a FBO and that FBO is bound.
-    // This must be paired with a call to unbindSurfaceFBOForPixelOps().
+    // Binds a surface as a FBO for copying, reading, or clearing. If the surface already owns an
+    // FBO ID then that ID is bound. If not the surface is temporarily bound to a FBO and that FBO
+    // is bound. This must be paired with a call to unbindSurfaceFBOForPixelOps().
     void bindSurfaceFBOForPixelOps(GrSurface* surface, GrGLenum fboTarget, GrGLIRect* viewport,
                                    TempFBOTarget tempFBOTarget);