Vertex color xform bench

Measures two different strategies for dealing with color space transform
of per-op colors. Assuming we already use vertex colors, is it better to
transform them on the CPU, and use float4 color attributes, or transform
them on the GPU, and use ubyte4 color attributes?

So far, looks like ubyte4 w/GPU transform wins.

Change-Id: If49d75303f669fe7f78af8771af906fa0e872577
Reviewed-on: https://skia-review.googlesource.com/142801
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

3 files changed, 282 insertions, 0 deletions

diff --git a/bench/VertexColorSpaceBench.cpp b/bench/VertexColorSpaceBench.cpp
new file mode 100644
index 0000000000..4e300b7689
--- /dev/null
+++ b/bench/VertexColorSpaceBench.cpp
@@ -0,0 +1,280 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Benchmark.h"
+
+#include "GrContext.h"
+#include "GrContextPriv.h"
+#include "GrGeometryProcessor.h"
+#include "GrMemoryPool.h"
+#include "GrRenderTargetContext.h"
+#include "GrRenderTargetContextPriv.h"
+#include "SkGr.h"
+#include "SkString.h"
+#include "glsl/GrGLSLColorSpaceXformHelper.h"
+#include "glsl/GrGLSLFragmentShaderBuilder.h"
+#include "glsl/GrGLSLGeometryProcessor.h"
+#include "glsl/GrGLSLVarying.h"
+#include "glsl/GrGLSLVertexGeoBuilder.h"
+#include "ops/GrMeshDrawOp.h"
+
+namespace {
+
+enum Mode {
+    kBaseline_Mode,  // Do the wrong thing, but quickly.
+    kFloat_Mode,     // Transform colors on CPU, use float4 attributes.
+    kShader_Mode,    // Use ubyte4 attributes, transform colors on GPU (vertex shader).
+};
+
+class GP : public GrGeometryProcessor {
+public:
+    GP(Mode mode, sk_sp<GrColorSpaceXform> colorSpaceXform)
+            : INHERITED(kVertexColorSpaceBenchGP_ClassID)
+            , fMode(mode)
+            , fColorSpaceXform(std::move(colorSpaceXform)) {
+        fInPosition = {"inPosition", kFloat2_GrVertexAttribType};
+        if (kFloat_Mode == fMode) {
+            fInColor = {"inColor", kFloat4_GrVertexAttribType};
+        } else {
+            fInColor = {"inColor", kUByte4_norm_GrVertexAttribType};
+        }
+        this->setVertexAttributeCnt(2);
+    }
+    const char* name() const override { return "VertexColorXformGP"; }
+
+    GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const override {
+        class GLSLGP : public GrGLSLGeometryProcessor {
+        public:
+            void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
+                const GP& gp = args.fGP.cast<GP>();
+                GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
+                GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
+                GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
+                GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
+
+                varyingHandler->emitAttributes(gp);
+
+                // Setup color
+                GrGLSLVarying varying(kHalf4_GrSLType);
+                varyingHandler->addVarying("color", &varying);
+                vertBuilder->codeAppendf("half4 color = %s;", gp.fInColor.name());
+
+                if (kShader_Mode == gp.fMode) {
+                    fColorSpaceHelper.emitCode(uniformHandler, gp.fColorSpaceXform.get(),
+                                               kVertex_GrShaderFlag);
+                    SkString xformedColor;
+                    vertBuilder->appendColorGamutXform(&xformedColor, "color", &fColorSpaceHelper);
+                    vertBuilder->codeAppendf("color = %s;", xformedColor.c_str());
+                    vertBuilder->codeAppend("color = half4(color.rgb * color.a, color.a);");
+                }
+
+                vertBuilder->codeAppendf("%s = color;", varying.vsOut());
+                fragBuilder->codeAppendf("%s = %s;", args.fOutputColor, varying.fsIn());
+
+                // Position
+                this->writeOutputPosition(args.fVertBuilder, gpArgs, gp.fInPosition.name());
+
+                // Coverage
+                fragBuilder->codeAppendf("%s = half4(1);", args.fOutputCoverage);
+            }
+            void setData(const GrGLSLProgramDataManager& pdman,
+                         const GrPrimitiveProcessor& primProc,
+                         FPCoordTransformIter&&) override {
+                const GP& gp = primProc.cast<GP>();
+                fColorSpaceHelper.setData(pdman, gp.fColorSpaceXform.get());
+            }
+
+            GrGLSLColorSpaceXformHelper fColorSpaceHelper;
+        };
+        return new GLSLGP();
+    }
+
+    void getGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder* b) const override {
+        b->add32(fMode);
+        b->add32(GrColorSpaceXform::XformKey(fColorSpaceXform.get()));
+    }
+
+private:
+    const GrPrimitiveProcessor::Attribute& onVertexAttribute(int i) const override {
+        return IthAttribute(i, fInPosition, fInColor);
+    }
+
+    Mode fMode;
+    sk_sp<GrColorSpaceXform> fColorSpaceXform;
+
+    Attribute fInPosition;
+    Attribute fInColor;
+
+    typedef GrGeometryProcessor INHERITED;
+};
+
+class Op : public GrMeshDrawOp {
+public:
+    DEFINE_OP_CLASS_ID
+
+    const char* name() const override { return "VertColorXformOp"; }
+
+    Op(GrColor color)
+            : INHERITED(ClassID())
+            , fMode(kBaseline_Mode)
+            , fColor(color) {
+        this->setBounds(SkRect::MakeWH(100.f, 100.f), HasAABloat::kNo, IsZeroArea::kNo);
+    }
+
+    Op(GrColor4f color4f)
+            : INHERITED(ClassID())
+            , fMode(kFloat_Mode)
+            , fColor4f(color4f) {
+        this->setBounds(SkRect::MakeWH(100.f, 100.f), HasAABloat::kNo, IsZeroArea::kNo);
+    }
+
+    Op(GrColor color, sk_sp<GrColorSpaceXform> colorSpaceXform)
+            : INHERITED(ClassID())
+            , fMode(kShader_Mode)
+            , fColor(color)
+            , fColorSpaceXform(std::move(colorSpaceXform)) {
+        this->setBounds(SkRect::MakeWH(100.f, 100.f), HasAABloat::kNo, IsZeroArea::kNo);
+    }
+
+    FixedFunctionFlags fixedFunctionFlags() const override {
+        return FixedFunctionFlags::kNone;
+    }
+
+    RequiresDstTexture finalize(const GrCaps&, const GrAppliedClip*) override {
+        return RequiresDstTexture::kNo;
+    }
+
+private:
+    friend class ::GrOpMemoryPool;
+
+    bool onCombineIfPossible(GrOp*, const GrCaps&) override { return false; }
+
+    void onPrepareDraws(Target* target) override {
+        sk_sp<GrGeometryProcessor> gp(new GP(fMode, fColorSpaceXform));
+
+        size_t vertexStride = sizeof(SkPoint) +
+                              ((kFloat_Mode == fMode) ? sizeof(GrColor4f) : sizeof(uint32_t));
+        SkASSERT(vertexStride == gp->debugOnly_vertexStride());
+
+        const int kVertexCount = 1024;
+        const GrBuffer* vertexBuffer = nullptr;
+        int firstVertex = 0;
+        void* verts = target->makeVertexSpace(vertexStride, kVertexCount, &vertexBuffer,
+                                              &firstVertex);
+        if (!verts) {
+            return;
+        }
+
+        const float dx = 100.0f / kVertexCount;
+        if (kFloat_Mode == fMode) {
+            struct V {
+                SkPoint fPos;
+                GrColor4f fColor;
+            };
+            SkASSERT(sizeof(V) == vertexStride);
+            V* v = (V*)verts;
+            for (int i = 0; i < kVertexCount; i += 2) {
+                v[i + 0].fPos.set(dx * i, 0.0f);
+                v[i + 0].fColor = fColor4f;
+                v[i + 1].fPos.set(dx * i, 100.0f);
+                v[i + 1].fColor = fColor4f;
+            }
+        } else {
+            struct V {
+                SkPoint fPos;
+                GrColor fColor;
+            };
+            SkASSERT(sizeof(V) == vertexStride);
+            V* v = (V*)verts;
+            for (int i = 0; i < kVertexCount; i += 2) {
+                v[i + 0].fPos.set(dx * i, 0.0f);
+                v[i + 0].fColor = fColor;
+                v[i + 1].fPos.set(dx * i, 100.0f);
+                v[i + 1].fColor = fColor;
+            }
+        }
+
+        GrMesh mesh(GrPrimitiveType::kTriangleStrip);
+        mesh.setNonIndexedNonInstanced(kVertexCount);
+        mesh.setVertexData(vertexBuffer, firstVertex);
+        auto pipe = target->makePipeline(0, GrProcessorSet::MakeEmptySet(),
+                                         target->detachAppliedClip());
+        target->draw(gp.get(), pipe.fPipeline, pipe.fFixedDynamicState, mesh);
+    }
+
+    Mode fMode;
+    GrColor fColor;
+    GrColor4f fColor4f;
+    sk_sp<GrColorSpaceXform> fColorSpaceXform;
+
+    typedef GrMeshDrawOp INHERITED;
+};
+}
+
+class VertexColorSpaceBench : public Benchmark {
+public:
+    VertexColorSpaceBench(Mode mode, const char* name) : fMode(mode) {
+        fName = "vertexcolorspace";
+        fName.appendf("_%s", name);
+    }
+
+    bool isSuitableFor(Backend backend) override { return kGPU_Backend == backend; }
+    const char* onGetName() override { return fName.c_str(); }
+
+    void onDraw(int loops, SkCanvas* canvas) override {
+        GrContext* context = canvas->getGrContext();
+        GrOpMemoryPool* pool = context->contextPriv().opMemoryPool();
+
+        SkASSERT(context);
+        auto p3 = SkColorSpace::MakeRGB(SkColorSpace::kSRGB_RenderTargetGamma,
+                                        SkColorSpace::kDCIP3_D65_Gamut);
+        auto xform = GrColorSpaceXform::MakeUnpremulToUnpremul(SkColorSpace::MakeSRGB().get(),
+                                                               p3.get());
+
+        SkRandom r;
+        const int kDrawsPerLoop = 32;
+
+        for (int i = 0; i < loops; ++i) {
+            sk_sp<GrRenderTargetContext> rtc(
+                    context->contextPriv().makeDeferredRenderTargetContext(SkBackingFit::kApprox,
+                    100, 100, kRGBA_8888_GrPixelConfig, p3));
+            SkASSERT(rtc);
+
+            for (int j = 0; j < kDrawsPerLoop; ++j) {
+                SkColor c = r.nextU();
+                std::unique_ptr<GrDrawOp> op = nullptr;
+
+                switch (fMode) {
+                    case kBaseline_Mode:
+                        op = pool->allocate<Op>(SkColorToPremulGrColor(c));
+                        break;
+                    case kShader_Mode:
+                        op = pool->allocate<Op>(SkColorToUnpremulGrColor(c), xform);
+                        break;
+                    case kFloat_Mode: {
+                        GrColor4f c4f = GrColor4f::FromGrColor(SkColorToUnpremulGrColor(c));
+                        c4f = xform->apply(c4f);
+                        op = pool->allocate<Op>(c4f);
+                    }
+                }
+                rtc->priv().testingOnly_addDrawOp(std::move(op));
+            }
+
+            context->flush();
+        }
+    }
+
+private:
+    SkString fName;
+    Mode fMode;
+
+    typedef Benchmark INHERITED;
+};
+
+DEF_BENCH(return new VertexColorSpaceBench(kBaseline_Mode, "baseline"));
+DEF_BENCH(return new VertexColorSpaceBench(kFloat_Mode,    "float"));
+DEF_BENCH(return new VertexColorSpaceBench(kShader_Mode,   "shader"));
diff --git a/gn/bench.gni b/gn/bench.gni
index 688636db57..b3b25611ec 100644
--- a/gn/bench.gni
+++ b/gn/bench.gni
@@ -121,6 +121,7 @@ bench_sources = [
   "$_bench/TileImageFilterBench.cpp",
   "$_bench/TopoSortBench.cpp",
   "$_bench/VertBench.cpp",
+  "$_bench/VertexColorSpaceBench.cpp",
   "$_bench/WritePixelsBench.cpp",
   "$_bench/WriterBench.cpp",
 ]
diff --git a/src/gpu/GrProcessor.h b/src/gpu/GrProcessor.h
index 038ce16717..4afc928da7 100644
--- a/src/gpu/GrProcessor.h
+++ b/src/gpu/GrProcessor.h
@@ -86,6 +86,7 @@ public:
         kEllipseGeometryProcessor_ClassID,
         kEllipticalRRectEffect_ClassID,
         kGP_ClassID,
+        kVertexColorSpaceBenchGP_ClassID,
         kGrAARectEffect_ClassID,
         kGrAlphaThresholdFragmentProcessor_ClassID,
         kGrArithmeticFP_ClassID,