text: /*
   * Copyright 2018 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  
  #include "gm/gm.h"
  #include "include/core/SkBlendMode.h"
  #include "include/core/SkCanvas.h"
  #include "include/core/SkColorSpace.h"
  #include "include/core/SkMatrix.h"
  #include "include/core/SkPoint.h"
  #include "include/core/SkRect.h"
  #include "include/core/SkRefCnt.h"
  #include "include/core/SkSize.h"
  #include "include/core/SkString.h"
  #include "include/core/SkTypes.h"
  #include "include/gpu/GrContext.h"
  #include "include/gpu/GrRecordingContext.h"
  #include "include/gpu/GrTypes.h"
  #include "include/private/GrTypesPriv.h"
  #include "include/private/SkColorData.h"
  #include "src/gpu/GrBuffer.h"
  #include "src/gpu/GrCaps.h"
  #include "src/gpu/GrColorSpaceXform.h"
  #include "src/gpu/GrContextPriv.h"
  #include "src/gpu/GrGeometryProcessor.h"
  #include "src/gpu/GrGpuBuffer.h"
  #include "src/gpu/GrMemoryPool.h"
  #include "src/gpu/GrOpFlushState.h"
  #include "src/gpu/GrOpsRenderPass.h"
  #include "src/gpu/GrPipeline.h"
  #include "src/gpu/GrPrimitiveProcessor.h"
  #include "src/gpu/GrProcessor.h"
  #include "src/gpu/GrProcessorSet.h"
  #include "src/gpu/GrProgramInfo.h"
  #include "src/gpu/GrRecordingContextPriv.h"
  #include "src/gpu/GrRenderTargetContext.h"
  #include "src/gpu/GrRenderTargetContextPriv.h"
  #include "src/gpu/GrResourceProvider.h"
  #include "src/gpu/GrSamplerState.h"
  #include "src/gpu/GrShaderCaps.h"
  #include "src/gpu/GrShaderVar.h"
  #include "src/gpu/GrSurfaceProxy.h"
  #include "src/gpu/GrTextureProxy.h"
  #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
  #include "src/gpu/glsl/GrGLSLGeometryProcessor.h"
  #include "src/gpu/glsl/GrGLSLPrimitiveProcessor.h"
  #include "src/gpu/glsl/GrGLSLVarying.h"
  #include "src/gpu/ops/GrDrawOp.h"
  #include "src/gpu/ops/GrOp.h"
  #include "tools/gpu/ProxyUtils.h"
  
  #include <memory>
  #include <utility>
  
  class GrAppliedClip;
  class GrGLSLProgramDataManager;
  
  namespace {
  
  static constexpr GrGeometryProcessor::Attribute gVertex =
          {"position", kFloat2_GrVertexAttribType, kFloat2_GrSLType};
  
  /**
   * This is a GPU-backend specific test. It ensures that SkSL properly identifies clockwise-winding
   * triangles (sk_Clockwise), in terms of to Skia device space, in all backends and with all render
   * target origins. We draw clockwise triangles green and counter-clockwise red.
   */
  class ClockwiseGM : public skiagm::GpuGM {
      SkString onShortName() override { return SkString("clockwise"); }
      SkISize onISize() override { return {300, 200}; }
      void onDraw(GrRecordingContext*, GrRenderTargetContext*, SkCanvas*) override;
  };
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  // SkSL code.
  
  class ClockwiseTestProcessor : public GrGeometryProcessor {
  public:
      static GrGeometryProcessor* Make(SkArenaAlloc* arena, bool readSkFragCoord) {
          return arena->make<ClockwiseTestProcessor>(readSkFragCoord);
      }
  
      const char* name() const final { return "ClockwiseTestProcessor"; }
  
      void getGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder* b) const final {
          b->add32(fReadSkFragCoord);
      }
  
      GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const final;
  
      bool readSkFragCoord() const { return fReadSkFragCoord; }
  
  private:
      friend class ::SkArenaAlloc; // for access to ctor
  
      ClockwiseTestProcessor(bool readSkFragCoord)
              : GrGeometryProcessor(kClockwiseTestProcessor_ClassID)
              , fReadSkFragCoord(readSkFragCoord) {
          this->setVertexAttributes(&gVertex, 1);
      }
  
      const bool fReadSkFragCoord;
  
      typedef GrGeometryProcessor INHERITED;
  };
  
  class GLSLClockwiseTestProcessor : public GrGLSLGeometryProcessor {
      void setData(const GrGLSLProgramDataManager& pdman, const GrPrimitiveProcessor&) override {}
  
      void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
          const ClockwiseTestProcessor& proc = args.fGP.cast<ClockwiseTestProcessor>();
          args.fVaryingHandler->emitAttributes(proc);
          gpArgs->fPositionVar.set(kFloat2_GrSLType, "position");
          args.fFragBuilder->codeAppendf(
                  "%s = sk_Clockwise ? half4(0,1,0,1) : half4(1,0,0,1);", args.fOutputColor);
          if (!proc.readSkFragCoord()) {
              args.fFragBuilder->codeAppendf("%s = half4(1);", args.fOutputCoverage);
          } else {
              // Verify layout(origin_upper_left) on gl_FragCoord does not affect gl_FrontFacing.
              args.fFragBuilder->codeAppendf("%s = half4(min(half(sk_FragCoord.y), 1));",
                                             args.fOutputCoverage);
          }
      }
  };
  
  GrGLSLPrimitiveProcessor* ClockwiseTestProcessor::createGLSLInstance(
          const GrShaderCaps&) const {
      return new GLSLClockwiseTestProcessor;
  }
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  // Draw Op.
  
  class ClockwiseTestOp : public GrDrawOp {
  public:
      DEFINE_OP_CLASS_ID
  
      static std::unique_ptr<GrDrawOp> Make(GrRecordingContext* context,
                                            bool readSkFragCoord, int y = 0) {
          GrOpMemoryPool* pool = context->priv().opMemoryPool();
          return pool->allocate<ClockwiseTestOp>(readSkFragCoord, y);
      }
  
  private:
      ClockwiseTestOp(bool readSkFragCoord, float y)
              : GrDrawOp(ClassID())
              , fReadSkFragCoord(readSkFragCoord)
              , fY(y) {
          this->setBounds(SkRect::MakeXYWH(0, fY, 100, 100), HasAABloat::kNo, IsHairline::kNo);
      }
  
      const char* name() const override { return "ClockwiseTestOp"; }
      FixedFunctionFlags fixedFunctionFlags() const override { return FixedFunctionFlags::kNone; }
      GrProcessorSet::Analysis finalize(const GrCaps&, const GrAppliedClip*,
                                        bool hasMixedSampledCoverage, GrClampType) override {
          return GrProcessorSet::EmptySetAnalysis();
      }
  
      GrProgramInfo* createProgramInfo(const GrCaps* caps,
                                       SkArenaAlloc* arena,
                                       const GrSurfaceProxyView* writeView,
                                       GrAppliedClip&& appliedClip,
                                       const GrXferProcessor::DstProxyView& dstProxyView) const {
          GrGeometryProcessor* geomProc = ClockwiseTestProcessor::Make(arena, fReadSkFragCoord);
  
          return sk_gpu_test::CreateProgramInfo(caps, arena, writeView,
                                                std::move(appliedClip), dstProxyView,
                                                geomProc, SkBlendMode::kPlus,
                                                GrPrimitiveType::kTriangleStrip);
      }
  
      GrProgramInfo* createProgramInfo(GrOpFlushState* flushState) const {
          return this->createProgramInfo(&flushState->caps(),
                                         flushState->allocator(),
                                         flushState->writeView(),
                                         flushState->detachAppliedClip(),
                                         flushState->dstProxyView());
      }
  
      void onPrePrepare(GrRecordingContext* context,
                        const GrSurfaceProxyView* writeView,
                        GrAppliedClip* clip,
                        const GrXferProcessor::DstProxyView& dstProxyView) final {
          SkArenaAlloc* arena = context->priv().recordTimeAllocator();
  
          // This is equivalent to a GrOpFlushState::detachAppliedClip
          GrAppliedClip appliedClip = clip ? std::move(*clip) : GrAppliedClip::Disabled();
  
          fProgramInfo = this->createProgramInfo(context->priv().caps(), arena, writeView,
                                                 std::move(appliedClip), dstProxyView);
  
          context->priv().recordProgramInfo(fProgramInfo);
      }
  
      void onPrepare(GrOpFlushState* flushState) override {
          SkPoint vertices[4] = {
              {100, fY},
              {0, fY+100},
              {0, fY},
              {100, fY+100},
          };
          fVertexBuffer = flushState->resourceProvider()->createBuffer(
                  sizeof(vertices), GrGpuBufferType::kVertex, kStatic_GrAccessPattern, vertices);
      }
  
      void onExecute(GrOpFlushState* flushState, const SkRect& chainBounds) override {
          if (!fVertexBuffer) {
              return;
          }
  
          if (!fProgramInfo) {
              fProgramInfo = this->createProgramInfo(flushState);
          }
  
          flushState->bindPipeline(*fProgramInfo, SkRect::MakeXYWH(0, fY, 100, 100));
          flushState->bindBuffers(nullptr, nullptr, fVertexBuffer.get());
          flushState->draw(4, 0);
      }
  
      sk_sp<GrBuffer> fVertexBuffer;
      const bool      fReadSkFragCoord;
      const float     fY;
  
      // The program info (and both the GrPipeline and GrPrimitiveProcessor it relies on), when
      // allocated, are allocated in either the ddl-record-time or flush-time arena. It is the
      // arena's job to free up their memory so we just have a bare programInfo pointer here. We
      // don't even store the GrPipeline and GrPrimitiveProcessor pointers here bc they are
      // guaranteed to have the same lifetime as the program info.
      GrProgramInfo*  fProgramInfo = nullptr;
  
      friend class ::GrOpMemoryPool; // for ctor
  
      typedef GrDrawOp INHERITED;
  };
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  // Test.
  
  void ClockwiseGM::onDraw(GrRecordingContext* ctx, GrRenderTargetContext* rtc, SkCanvas* canvas) {
      rtc->clear(SK_PMColor4fBLACK);
  
      // Draw the test directly to the frame buffer.
      rtc->priv().testingOnly_addDrawOp(ClockwiseTestOp::Make(ctx, false, 0));
      rtc->priv().testingOnly_addDrawOp(ClockwiseTestOp::Make(ctx, true, 100));
  
      // Draw the test to an off-screen, top-down render target.
      GrColorType rtcColorType = rtc->colorInfo().colorType();
      if (auto topLeftRTC = GrRenderTargetContext::Make(
                  ctx, rtcColorType, nullptr, SkBackingFit::kExact, {100, 200}, 1,
                  GrMipMapped::kNo, GrProtected::kNo, kTopLeft_GrSurfaceOrigin, SkBudgeted::kYes,
                  nullptr)) {
          topLeftRTC->clear(SK_PMColor4fTRANSPARENT);
          topLeftRTC->priv().testingOnly_addDrawOp(ClockwiseTestOp::Make(ctx, false, 0));
          topLeftRTC->priv().testingOnly_addDrawOp(ClockwiseTestOp::Make(ctx, true, 100));
          rtc->drawTexture(nullptr, topLeftRTC->readSurfaceView(), rtc->colorInfo().alphaType(),
                           GrSamplerState::Filter::kNearest, SkBlendMode::kSrcOver, SK_PMColor4fWHITE,
                           {0, 0, 100, 200}, {100, 0, 200, 200}, GrAA::kNo, GrQuadAAFlags::kNone,
                           SkCanvas::SrcRectConstraint::kStrict_SrcRectConstraint, SkMatrix::I(),
                           nullptr);
      }
  
      // Draw the test to an off-screen, bottom-up render target.
      if (auto topLeftRTC = GrRenderTargetContext::Make(
                  ctx, rtcColorType, nullptr, SkBackingFit::kExact, {100, 200}, 1,
                  GrMipMapped::kNo, GrProtected::kNo, kBottomLeft_GrSurfaceOrigin, SkBudgeted::kYes,
                  nullptr)) {
          topLeftRTC->clear(SK_PMColor4fTRANSPARENT);
          topLeftRTC->priv().testingOnly_addDrawOp(ClockwiseTestOp::Make(ctx, false, 0));
          topLeftRTC->priv().testingOnly_addDrawOp(ClockwiseTestOp::Make(ctx, true, 100));
          rtc->drawTexture(nullptr, topLeftRTC->readSurfaceView(), rtc->colorInfo().alphaType(),
                           GrSamplerState::Filter::kNearest, SkBlendMode::kSrcOver, SK_PMColor4fWHITE,
                           {0, 0, 100, 200}, {200, 0, 300, 200}, GrAA::kNo, GrQuadAAFlags::kNone,
                           SkCanvas::SrcRectConstraint::kStrict_SrcRectConstraint, SkMatrix::I(),
                           nullptr);
      }
  }
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  
  DEF_GM( return new ClockwiseGM(); )
  
  }
  