Don't flush on read/write pixels unless necessary

BUG=skia:2889

Committed: https://skia.googlesource.com/skia/+/150723b9298772a5096bec7acd2999c5c9d66239

R=robertphillips@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/586073002

include/gpu/GrGpuResource.h

@@ -80,9 +80,14 @@ public:
 #endif
     }
 
+
 protected:
     GrIORef() : fRefCnt(1), fPendingReads(0), fPendingWrites(0) {}
 
+    bool internalHasPendingRead() const { return SkToBool(fPendingReads); }
+    bool internalHasPendingWrite() const { return SkToBool(fPendingWrites); }
+    bool internalHasPendingIO() const { return SkToBool(fPendingWrites | fPendingReads); }
+
 private:
     void addPendingRead() const {
         this->validate();

include/gpu/GrSurface.h

@@ -135,6 +135,10 @@ public:
      */
     bool savePixels(const char* filename);
 
+    bool hasPendingRead() const;
+    bool hasPendingWrite() const;
+    bool hasPendingIO() const;
+
 protected:
     GrSurface(GrGpu* gpu, bool isWrapped, const GrTextureDesc& desc)
     : INHERITED(gpu, isWrapped)

src/gpu/GrContext.cpp

@@ -1347,7 +1347,7 @@ bool GrContext::writeTexturePixels(GrTexture* texture,
         }
     }
 
-    if (!(kDontFlush_PixelOpsFlag & flags)) {
+    if (!(kDontFlush_PixelOpsFlag & flags) && texture->hasPendingIO()) {
         this->flush();
     }
 
@@ -1418,7 +1418,7 @@ bool GrContext::readRenderTargetPixels(GrRenderTarget* target,
         }
     }
 
-    if (!(kDontFlush_PixelOpsFlag & flags)) {
+    if (!(kDontFlush_PixelOpsFlag & flags) && target->hasPendingWrite()) {
         this->flush();
     }
 
@@ -1578,11 +1578,10 @@ void GrContext::copyTexture(GrTexture* src, GrRenderTarget* dst, const SkIPoint*
     }
     ASSERT_OWNED_RESOURCE(src);
 
-    // Writes pending to the source texture are not tracked, so a flush
-    // is required to ensure that the copy captures the most recent contents
-    // of the source texture. See similar behavior in
-    // GrContext::resolveRenderTarget.
-    this->flush();
+
+    if (src->hasPendingWrite() || dst->hasPendingIO()) {
+        this->flush();
+    }
 
     GrDrawTarget::AutoStateRestore asr(fGpu, GrDrawTarget::kReset_ASRInit);
     GrDrawState* drawState = fGpu->drawState();
@@ -1715,9 +1714,15 @@ bool GrContext::writeRenderTargetPixels(GrRenderTarget* target,
         return false;
     }
 
+    // TODO: Usually this could go to fDrawBuffer but currently
     // writeRenderTargetPixels can be called in the midst of drawing another
     // object (e.g., when uploading a SW path rendering to the gpu while
-    // drawing a rect) so preserve the current geometry.
+    // drawing a rect). So we always draw directly to GrGpu and preserve the current geometry.
+    // But that means we also have to flush the draw buffer if there is a pending IO operation to
+    // the render target.
+    if (!(kDontFlush_PixelOpsFlag & flags) && target->hasPendingIO()) {
+        this->flush();
+    }
     SkMatrix matrix;
     matrix.setTranslate(SkIntToScalar(left), SkIntToScalar(top));
     GrDrawTarget::AutoGeometryAndStatePush agasp(fGpu, GrDrawTarget::kReset_ASRInit, &matrix);

src/gpu/GrInOrderDrawBuffer.cpp

@@ -833,7 +833,7 @@ void GrInOrderDrawBuffer::geometrySourceWillPop(const GeometrySrcState& restored
 
 void GrInOrderDrawBuffer::recordStateIfNecessary() {
     if (fStates.empty()) {
-        fStates.push_back() = this->getDrawState();
+        this->convertDrawStateToPendingExec(&fStates.push_back(this->getDrawState()));
         this->addToCmdBuffer(kSetState_Cmd);
         return;
     }

src/gpu/GrSurface.cpp

@@ -44,3 +44,39 @@ bool GrSurface::savePixels(const char* filename) {
 
     return true;
 }
+
+bool GrSurface::hasPendingRead() const {
+    const GrTexture* thisTex = this->asTexture();
+    if (thisTex && thisTex->internalHasPendingRead()) {
+        return true;
+    }
+    const GrRenderTarget* thisRT = this->asRenderTarget();
+    if (thisRT && thisRT->internalHasPendingRead()) {
+        return true;
+    }
+    return false;
+}
+
+bool GrSurface::hasPendingWrite() const {
+    const GrTexture* thisTex = this->asTexture();
+    if (thisTex && thisTex->internalHasPendingWrite()) {
+        return true;
+    }
+    const GrRenderTarget* thisRT = this->asRenderTarget();
+    if (thisRT && thisRT->internalHasPendingWrite()) {
+        return true;
+    }
+    return false;
+}
+
+bool GrSurface::hasPendingIO() const {
+    const GrTexture* thisTex = this->asTexture();
+    if (thisTex && thisTex->internalHasPendingIO()) {
+        return true;
+    }
+    const GrRenderTarget* thisRT = this->asRenderTarget();
+    if (thisRT && thisRT->internalHasPendingIO()) {
+        return true;
+    }
+    return false;
+}