Create indirect index buffer for tessellation during onPrepare

Change-Id: I78d74976fa2252da2a40862c241a99b68d27fb40
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/292259
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>

bench/TessellatePathBench.cpp

@@ -34,6 +34,26 @@ static SkPath make_cubic_path() {
 // pre-allocated CPU buffers, rather than allocating and mapping GPU buffers.
 class BenchmarkTarget : public GrMeshDrawOp::Target {
 public:
+    BenchmarkTarget() {
+        GrMockOptions mockOptions;
+        mockOptions.fDrawInstancedSupport = true;
+        mockOptions.fTessellationSupport = true;
+        mockOptions.fMapBufferFlags = GrCaps::kCanMap_MapFlag;
+        mockOptions.fConfigOptions[(int)GrColorType::kAlpha_8].fRenderability =
+                GrMockOptions::ConfigOptions::Renderability::kMSAA;
+        mockOptions.fConfigOptions[(int)GrColorType::kAlpha_8].fTexturable = true;
+        mockOptions.fIntegerSupport = true;
+
+        GrContextOptions ctxOptions;
+        ctxOptions.fGpuPathRenderers = GpuPathRenderers::kTessellation;
+
+        fMockContext = GrContext::MakeMock(&mockOptions, ctxOptions);
+    }
+    const GrContext* mockContext() const { return fMockContext.get(); }
+    const GrCaps& caps() const override { return *fMockContext->priv().caps(); }
+    GrResourceProvider* resourceProvider() const override {
+        return fMockContext->priv().resourceProvider();
+    }
     void resetAllocator() { fAllocator.reset(); }
     SkArenaAlloc* allocator() override { return &fAllocator; }
     void putBackVertices(int vertices, size_t vertexStride) override { /* no-op */ }
@@ -73,15 +93,14 @@ public:
     UNIMPL(const GrAppliedClip* appliedClip() const)
     UNIMPL(GrAppliedClip detachAppliedClip())
     UNIMPL(const GrXferProcessor::DstProxyView& dstProxyView() const)
-    UNIMPL(GrResourceProvider* resourceProvider() const)
     UNIMPL(GrStrikeCache* strikeCache() const)
     UNIMPL(GrAtlasManager* atlasManager() const)
     UNIMPL(SkTArray<GrSurfaceProxy*, true>* sampledProxyArray())
-    UNIMPL(const GrCaps& caps() const)
     UNIMPL(GrDeferredUploadTarget* deferredUploadTarget())
 #undef UNIMPL
 
 private:
+    sk_sp<GrContext> fMockContext;
     SkPoint fStaticVertexData[(kNumCubicsInChalkboard + 2) * 8];
     GrDrawIndexedIndirectCommand fStaticDrawIndexedIndirectData[32];
     SkSTArenaAlloc<1024 * 1024> fAllocator;
@@ -110,6 +129,10 @@ public:
 
 private:
     void onDraw(int loops, SkCanvas*) final {
+        if (!fTarget.mockContext()) {
+            SkDebugf("ERROR: could not create mock context.");
+            return;
+        }
         for (int i = 0; i < loops; ++i) {
             fOp.fTriangleBuffer.reset();
             fOp.fDoStencilTriangleBuffer = false;

src/gpu/tessellate/GrTessellatePathOp.cpp

@@ -275,10 +275,17 @@ void GrTessellatePathOp::prepareIndirectOuterCubics(
 void GrTessellatePathOp::prepareIndirectOuterCubicsAndTriangles(
         GrMeshDrawOp::Target* target, const GrResolveLevelCounter& resolveLevelCounter,
         SkPoint* cubicData, int numTrianglesAtBeginningOfData) {
+    SkASSERT(target->caps().drawInstancedSupport());
     SkASSERT(numTrianglesAtBeginningOfData + resolveLevelCounter.totalCubicInstanceCount() > 0);
     SkASSERT(!fStencilCubicsShader);
     SkASSERT(cubicData);
 
+    fIndirectIndexBuffer = GrMiddleOutCubicShader::FindOrMakeMiddleOutIndexBuffer(
+            target->resourceProvider());
+    if (!fIndirectIndexBuffer) {
+        return;
+    }
+
     // Here we treat fCubicBuffer as an instance buffer. It should have been prepared with the base
     // vertex on an instance boundary in order to accommodate this.
     SkASSERT(fBaseCubicVertex % 4 == 0);
@@ -378,6 +385,7 @@ void GrTessellatePathOp::prepareIndirectOuterCubicsAndTriangles(
 
 void GrTessellatePathOp::prepareTessellatedOuterCubics(GrMeshDrawOp::Target* target,
                                                        int numCountedCurves) {
+    SkASSERT(target->caps().shaderCaps()->tessellationSupport());
     SkASSERT(numCountedCurves >= 0);
     SkASSERT(!fCubicBuffer);
     SkASSERT(!fStencilCubicsShader);
@@ -414,6 +422,7 @@ void GrTessellatePathOp::prepareTessellatedOuterCubics(GrMeshDrawOp::Target* tar
 }
 
 void GrTessellatePathOp::prepareTessellatedCubicWedges(GrMeshDrawOp::Target* target) {
+    SkASSERT(target->caps().shaderCaps()->tessellationSupport());
     SkASSERT(!fCubicBuffer);
     SkASSERT(!fStencilCubicsShader);
 
@@ -531,9 +540,8 @@ void GrTessellatePathOp::drawStencilPass(GrOpFlushState* flushState) {
                                               fStencilCubicsShader);
         flushState->bindPipelineAndScissorClip(programInfo, this->bounds());
         if (fIndirectDrawBuffer) {
-            auto indexBuffer = GrMiddleOutCubicShader::FindOrMakeMiddleOutIndexBuffer(
-                    flushState->resourceProvider());
-            flushState->bindBuffers(indexBuffer.get(), fCubicBuffer.get(), nullptr);
+            SkASSERT(fIndirectIndexBuffer);
+            flushState->bindBuffers(fIndirectIndexBuffer.get(), fCubicBuffer.get(), nullptr);
             flushState->drawIndexedIndirect(fIndirectDrawBuffer.get(), fIndirectDrawOffset,
                                             fIndirectDrawCount);
         } else {

src/gpu/tessellate/GrTessellatePathOp.h

@@ -160,6 +160,7 @@ private:
     sk_sp<const GrBuffer> fIndirectDrawBuffer;
     size_t fIndirectDrawOffset;
     int fIndirectDrawCount;
+    sk_sp<const GrBuffer> fIndirectIndexBuffer;
 
     friend class GrOpMemoryPool;  // For ctor.