text: /*
   * Copyright 2015 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  
  #include "src/gpu/ganesh/ops/LatticeOp.h"
  
  #include "include/core/SkBitmap.h"
  #include "include/core/SkRect.h"
  #include "src/core/SkLatticeIter.h"
  #include "src/core/SkMatrixPriv.h"
  #include "src/gpu/BufferWriter.h"
  #include "src/gpu/KeyBuilder.h"
  #include "src/gpu/ganesh/GrGeometryProcessor.h"
  #include "src/gpu/ganesh/GrGpu.h"
  #include "src/gpu/ganesh/GrOpFlushState.h"
  #include "src/gpu/ganesh/GrProgramInfo.h"
  #include "src/gpu/ganesh/GrResourceProvider.h"
  #include "src/gpu/ganesh/GrResourceProviderPriv.h"
  #include "src/gpu/ganesh/SkGr.h"
  #include "src/gpu/ganesh/glsl/GrGLSLColorSpaceXformHelper.h"
  #include "src/gpu/ganesh/glsl/GrGLSLFragmentShaderBuilder.h"
  #include "src/gpu/ganesh/glsl/GrGLSLVarying.h"
  #include "src/gpu/ganesh/ops/GrMeshDrawOp.h"
  #include "src/gpu/ganesh/ops/GrSimpleMeshDrawOpHelper.h"
  
  namespace skgpu::v1::LatticeOp {
  
  namespace {
  
  class LatticeGP : public GrGeometryProcessor {
  public:
      static GrGeometryProcessor* Make(SkArenaAlloc* arena,
                                       const GrSurfaceProxyView& view,
                                       sk_sp<GrColorSpaceXform> csxf,
                                       GrSamplerState::Filter filter,
                                       bool wideColor) {
          return arena->make([&](void* ptr) {
              return new (ptr) LatticeGP(view, std::move(csxf), filter, wideColor);
          });
      }
  
      const char* name() const override { return "LatticeGP"; }
  
      void addToKey(const GrShaderCaps&, KeyBuilder* b) const override {
          b->add32(GrColorSpaceXform::XformKey(fColorSpaceXform.get()));
      }
  
      std::unique_ptr<ProgramImpl> makeProgramImpl(const GrShaderCaps&) const override {
          class Impl : public ProgramImpl {
          public:
              void setData(const GrGLSLProgramDataManager& pdman,
                           const GrShaderCaps&,
                           const GrGeometryProcessor& geomProc) override {
                  const auto& latticeGP = geomProc.cast<LatticeGP>();
                  fColorSpaceXformHelper.setData(pdman, latticeGP.fColorSpaceXform.get());
              }
  
          private:
              void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
                  using Interpolation = GrGLSLVaryingHandler::Interpolation;
                  const auto& latticeGP = args.fGeomProc.cast<LatticeGP>();
                  fColorSpaceXformHelper.emitCode(args.fUniformHandler,
                                                  latticeGP.fColorSpaceXform.get());
  
                  args.fVaryingHandler->emitAttributes(latticeGP);
                  WriteOutputPosition(args.fVertBuilder, gpArgs, latticeGP.fInPosition.name());
                  gpArgs->fLocalCoordVar = latticeGP.fInTextureCoords.asShaderVar();
  
                  args.fFragBuilder->codeAppend("float2 textureCoords;");
                  args.fVaryingHandler->addPassThroughAttribute(
                          latticeGP.fInTextureCoords.asShaderVar(),
                          "textureCoords");
                  args.fFragBuilder->codeAppend("float4 textureDomain;");
                  args.fVaryingHandler->addPassThroughAttribute(
                          latticeGP.fInTextureDomain.asShaderVar(),
                          "textureDomain",
                          Interpolation::kCanBeFlat);
                  args.fFragBuilder->codeAppendf("half4 %s;", args.fOutputColor);
                  args.fVaryingHandler->addPassThroughAttribute(latticeGP.fInColor.asShaderVar(),
                                                                args.fOutputColor,
                                                                Interpolation::kCanBeFlat);
                  args.fFragBuilder->codeAppendf("%s = ", args.fOutputColor);
                  args.fFragBuilder->appendTextureLookupAndBlend(
                          args.fOutputColor,
                          SkBlendMode::kModulate,
                          args.fTexSamplers[0],
                          "clamp(textureCoords, textureDomain.xy, textureDomain.zw)",
                          &fColorSpaceXformHelper);
                  args.fFragBuilder->codeAppend(";");
                  args.fFragBuilder->codeAppendf("const half4 %s = half4(1);", args.fOutputCoverage);
              }
  
              GrGLSLColorSpaceXformHelper fColorSpaceXformHelper;
          };
  
          return std::make_unique<Impl>();
      }
  
  private:
      LatticeGP(const GrSurfaceProxyView& view, sk_sp<GrColorSpaceXform> csxf,
                GrSamplerState::Filter filter, bool wideColor)
              : INHERITED(kLatticeGP_ClassID)
              , fColorSpaceXform(std::move(csxf)) {
  
          fSampler.reset(GrSamplerState(GrSamplerState::WrapMode::kClamp, filter),
                         view.proxy()->backendFormat(), view.swizzle());
          this->setTextureSamplerCnt(1);
          fInPosition = {"position", kFloat2_GrVertexAttribType, SkSLType::kFloat2};
          fInTextureCoords = {"textureCoords", kFloat2_GrVertexAttribType, SkSLType::kFloat2};
          fInTextureDomain = {"textureDomain", kFloat4_GrVertexAttribType, SkSLType::kFloat4};
          fInColor = MakeColorAttribute("color", wideColor);
          this->setVertexAttributesWithImplicitOffsets(&fInPosition, 4);
      }
  
      const TextureSampler& onTextureSampler(int) const override { return fSampler; }
  
      Attribute fInPosition;
      Attribute fInTextureCoords;
      Attribute fInTextureDomain;
      Attribute fInColor;
  
      sk_sp<GrColorSpaceXform> fColorSpaceXform;
      TextureSampler fSampler;
  
      using INHERITED = GrGeometryProcessor;
  };
  
  class NonAALatticeOp final : public GrMeshDrawOp {
  private:
      using Helper = GrSimpleMeshDrawOpHelper;
  
  public:
      DEFINE_OP_CLASS_ID
  
      static GrOp::Owner Make(GrRecordingContext* context,
                              GrPaint&& paint,
                              const SkMatrix& viewMatrix,
                              GrSurfaceProxyView view,
                              SkAlphaType alphaType,
                              sk_sp<GrColorSpaceXform> colorSpaceXForm,
                              GrSamplerState::Filter filter,
                              std::unique_ptr<SkLatticeIter> iter,
                              const SkRect& dst) {
          SkASSERT(view.proxy());
          return Helper::FactoryHelper<NonAALatticeOp>(context, std::move(paint), viewMatrix,
                                                       std::move(view), alphaType,
                                                       std::move(colorSpaceXForm), filter,
                                                       std::move(iter), dst);
      }
  
      NonAALatticeOp(GrProcessorSet* processorSet, const SkPMColor4f& color,
                     const SkMatrix& viewMatrix, GrSurfaceProxyView view,
                     SkAlphaType alphaType, sk_sp<GrColorSpaceXform> colorSpaceXform,
                     GrSamplerState::Filter filter, std::unique_ptr<SkLatticeIter> iter,
                     const SkRect& dst)
              : INHERITED(ClassID())
              , fHelper(processorSet, GrAAType::kNone)
              , fView(std::move(view))
              , fAlphaType(alphaType)
              , fColorSpaceXform(std::move(colorSpaceXform))
              , fFilter(filter) {
          Patch& patch = fPatches.push_back();
          patch.fViewMatrix = viewMatrix;
          patch.fColor = color;
          patch.fIter = std::move(iter);
          patch.fDst = dst;
  
          // setup bounds
          this->setTransformedBounds(patch.fDst, viewMatrix, HasAABloat::kNo, IsHairline::kNo);
      }
  
      const char* name() const override { return "NonAALatticeOp"; }
  
      void visitProxies(const GrVisitProxyFunc& func) const override {
          func(fView.proxy(), GrMipmapped::kNo);
          if (fProgramInfo) {
              fProgramInfo->visitFPProxies(func);
          } else {
              fHelper.visitProxies(func);
          }
      }
  
      FixedFunctionFlags fixedFunctionFlags() const override { return fHelper.fixedFunctionFlags(); }
  
      GrProcessorSet::Analysis finalize(const GrCaps& caps, const GrAppliedClip* clip,
                                        GrClampType clampType) override {
          auto opaque = fPatches[0].fColor.isOpaque() && fAlphaType == kOpaque_SkAlphaType
                                ? GrProcessorAnalysisColor::Opaque::kYes
                                : GrProcessorAnalysisColor::Opaque::kNo;
          auto analysisColor = GrProcessorAnalysisColor(opaque);
          auto result = fHelper.finalizeProcessors(caps, clip, clampType,
                                                   GrProcessorAnalysisCoverage::kNone,
                                                   &analysisColor);
          analysisColor.isConstant(&fPatches[0].fColor);
          fWideColor = !fPatches[0].fColor.fitsInBytes();
          return result;
      }
  
  private:
      GrProgramInfo* programInfo() override { return fProgramInfo; }
  
      void onCreateProgramInfo(const GrCaps* caps,
                               SkArenaAlloc* arena,
                               const GrSurfaceProxyView& writeView,
                               bool usesMSAASurface,
                               GrAppliedClip&& appliedClip,
                               const GrDstProxyView& dstProxyView,
                               GrXferBarrierFlags renderPassXferBarriers,
                               GrLoadOp colorLoadOp) override {
  
          auto gp = LatticeGP::Make(arena, fView, fColorSpaceXform, fFilter, fWideColor);
          if (!gp) {
              return;
          }
  
          fProgramInfo = GrSimpleMeshDrawOpHelper::CreateProgramInfo(caps, arena, writeView,
                                                                     usesMSAASurface,
                                                                     std::move(appliedClip),
                                                                     dstProxyView, gp,
                                                                     fHelper.detachProcessorSet(),
                                                                     GrPrimitiveType::kTriangles,
                                                                     renderPassXferBarriers,
                                                                     colorLoadOp,
                                                                     fHelper.pipelineFlags(),
                                                                     &GrUserStencilSettings::kUnused);
      }
  
      void onPrepareDraws(GrMeshDrawTarget* target) override {
          if (!fProgramInfo) {
              this->createProgramInfo(target);
              if (!fProgramInfo) {
                  return;
              }
          }
  
          int patchCnt = fPatches.count();
          int numRects = 0;
          for (int i = 0; i < patchCnt; i++) {
              numRects += fPatches[i].fIter->numRectsToDraw();
          }
  
          if (!numRects) {
              return;
          }
  
          const size_t kVertexStride = fProgramInfo->geomProc().vertexStride();
  
          QuadHelper helper(target, kVertexStride, numRects);
  
          VertexWriter vertices{helper.vertices()};
          if (!vertices) {
              SkDebugf("Could not allocate vertices\n");
              return;
          }
  
          for (int i = 0; i < patchCnt; i++) {
              const Patch& patch = fPatches[i];
  
              VertexColor patchColor(patch.fColor, fWideColor);
  
              // Apply the view matrix here if it is scale-translate.  Otherwise, we need to
              // wait until we've created the dst rects.
              bool isScaleTranslate = patch.fViewMatrix.isScaleTranslate();
              if (isScaleTranslate) {
                  patch.fIter->mapDstScaleTranslate(patch.fViewMatrix);
              }
  
              SkIRect srcR;
              SkRect dstR;
              skvx::float4 scales(1.f / fView.proxy()->width(), 1.f / fView.proxy()->height(),
                                  1.f / fView.proxy()->width(), 1.f / fView.proxy()->height());
              static const skvx::float4 kDomainOffsets(0.5f, 0.5f, -0.5f, -0.5f);
              static const skvx::float4 kFlipOffsets(0.f, 1.f, 0.f, 1.f);
              static const skvx::float4 kFlipMuls(1.f, -1.f, 1.f, -1.f);
              while (patch.fIter->next(&srcR, &dstR)) {
                  skvx::float4 coords(SkIntToScalar(srcR.fLeft), SkIntToScalar(srcR.fTop),
                                      SkIntToScalar(srcR.fRight), SkIntToScalar(srcR.fBottom));
                  skvx::float4 domain = coords + kDomainOffsets;
                  coords *= scales;
                  domain *= scales;
                  if (fView.origin() == kBottomLeft_GrSurfaceOrigin) {
                      coords = kFlipMuls * coords + kFlipOffsets;
                      domain = skvx::shuffle<0, 3, 2, 1>(kFlipMuls * domain + kFlipOffsets);
                  }
                  SkRect texDomain;
                  SkRect texCoords;
                  domain.store(&texDomain);
                  coords.store(&texCoords);
  
                  if (isScaleTranslate) {
                      vertices.writeQuad(VertexWriter::TriStripFromRect(dstR),
                                         VertexWriter::TriStripFromRect(texCoords),
                                         texDomain,
                                         patchColor);
                  } else {
                      SkPoint mappedPts[4];
                      patch.fViewMatrix.mapRectToQuad(mappedPts, dstR);
                      // In the above if statement, writeQuad writes the corners as:
                      // left-top, left-bottom, right-top, right-bottom.
                      // However, mapRectToQuad returns them in the order:
                      // left-top, right-top, right-bottom, left-bottom
                      // Thus we write out the vertices to match the writeQuad path.
                      vertices << mappedPts[0]
                               << SkPoint::Make(texCoords.fLeft, texCoords.fTop)
                               << texDomain
                               << patchColor;
                      vertices << mappedPts[3]
                               << SkPoint::Make(texCoords.fLeft, texCoords.fBottom)
                               << texDomain
                               << patchColor;
                      vertices << mappedPts[1]
                               << SkPoint::Make(texCoords.fRight, texCoords.fTop)
                               << texDomain
                               << patchColor;
                      vertices << mappedPts[2]
                               << SkPoint::Make(texCoords.fRight, texCoords.fBottom)
                               << texDomain
                               << patchColor;
                  }
              }
          }
  
          fMesh = helper.mesh();
      }
  
      void onExecute(GrOpFlushState* flushState, const SkRect& chainBounds) override {
          if (!fProgramInfo || !fMesh) {
              return;
          }
  
          flushState->bindPipelineAndScissorClip(*fProgramInfo, chainBounds);
          flushState->bindTextures(fProgramInfo->geomProc(),
                                   *fView.proxy(),
                                   fProgramInfo->pipeline());
          flushState->drawMesh(*fMesh);
      }
  
      CombineResult onCombineIfPossible(GrOp* t, SkArenaAlloc*, const GrCaps& caps) override {
          NonAALatticeOp* that = t->cast<NonAALatticeOp>();
          if (fView != that->fView) {
              return CombineResult::kCannotCombine;
          }
          if (fFilter != that->fFilter) {
              return CombineResult::kCannotCombine;
          }
          if (GrColorSpaceXform::Equals(fColorSpaceXform.get(), that->fColorSpaceXform.get())) {
              return CombineResult::kCannotCombine;
          }
          if (!fHelper.isCompatible(that->fHelper, caps, this->bounds(), that->bounds())) {
              return CombineResult::kCannotCombine;
          }
  
          fPatches.move_back_n(that->fPatches.count(), that->fPatches.begin());
          fWideColor |= that->fWideColor;
          return CombineResult::kMerged;
      }
  
  #if GR_TEST_UTILS
      SkString onDumpInfo() const override {
          SkString str;
  
          for (int i = 0; i < fPatches.count(); ++i) {
              str.appendf("%d: Color: 0x%08x Dst [L: %.2f, T: %.2f, R: %.2f, B: %.2f]\n", i,
                          fPatches[i].fColor.toBytes_RGBA(), fPatches[i].fDst.fLeft,
                          fPatches[i].fDst.fTop, fPatches[i].fDst.fRight, fPatches[i].fDst.fBottom);
          }
  
          str += fHelper.dumpInfo();
          return str;
      }
  #endif
  
      struct Patch {
          SkMatrix fViewMatrix;
          std::unique_ptr<SkLatticeIter> fIter;
          SkRect fDst;
          SkPMColor4f fColor;
      };
  
      Helper fHelper;
      SkSTArray<1, Patch, true> fPatches;
      GrSurfaceProxyView fView;
      SkAlphaType fAlphaType;
      sk_sp<GrColorSpaceXform> fColorSpaceXform;
      GrSamplerState::Filter fFilter;
      bool fWideColor;
  
      GrSimpleMesh*  fMesh = nullptr;
      GrProgramInfo* fProgramInfo = nullptr;
  
      using INHERITED = GrMeshDrawOp;
  };
  
  }  // anonymous namespace
  
  GrOp::Owner MakeNonAA(GrRecordingContext* context,
                        GrPaint&& paint,
                        const SkMatrix& viewMatrix,
                        GrSurfaceProxyView view,
                        SkAlphaType alphaType,
                        sk_sp<GrColorSpaceXform> colorSpaceXform,
                        GrSamplerState::Filter filter,
                        std::unique_ptr<SkLatticeIter> iter,
                        const SkRect& dst) {
      return NonAALatticeOp::Make(context, std::move(paint), viewMatrix, std::move(view), alphaType,
                                  std::move(colorSpaceXform), filter, std::move(iter), dst);
  }
  
  }  // namespace skgpu::v1::LatticeOp
  
  #if GR_TEST_UTILS
  #include "src/gpu/ganesh/GrDrawOpTest.h"
  #include "src/gpu/ganesh/GrProxyProvider.h"
  #include "src/gpu/ganesh/GrRecordingContextPriv.h"
  
  /** Randomly divides subset into count divs. */
  static void init_random_divs(int divs[], int count, int subsetStart, int subsetStop,
                               SkRandom* random) {
      // Rules for lattice divs: Must be strictly increasing and in the range
      // [subsetStart, subsetStop.
      // Not terribly efficient alg for generating random divs:
      // 1 Start with minimum legal pixels between each div.
      // 2) Randomly assign the remaining pixels of the subset to divs.
      // 3) Convert from pixel counts to div offsets.
  
      // 1) Initially each divs[i] represents the number of pixels between
      // div i-1 and i. The initial div is allowed to be at subsetStart. There
      // must be one pixel spacing between subsequent divs.
      divs[0] = 0;
      for (int i = 1; i < count; ++i) {
          divs[i] = 1;
      }
      // 2) Assign the remaining subset pixels to fall
      int subsetLength = subsetStop - subsetStart;
      for (int i = 0; i < subsetLength - count; ++i) {
          // +1 because count divs means count+1 intervals.
          int entry = random->nextULessThan(count + 1);
          // We don't have an entry to  to store the count after the last div
          if (entry < count) {
              divs[entry]++;
          }
      }
      // 3) Now convert the counts between divs to pixel indices, incorporating the subset's offset.
      int offset = subsetStart;
      for (int i = 0; i < count; ++i) {
          divs[i] += offset;
          offset = divs[i];
      }
  }
  
  GR_DRAW_OP_TEST_DEFINE(NonAALatticeOp) {
      SkCanvas::Lattice lattice;
      // We loop because our random lattice code can produce an invalid lattice in the case where
      // there is a single div separator in both x and y and both are aligned with the left and top
      // edge of the image subset, respectively.
      std::unique_ptr<int[]> xdivs;
      std::unique_ptr<int[]> ydivs;
      std::unique_ptr<SkCanvas::Lattice::RectType[]> flags;
      std::unique_ptr<SkColor[]> colors;
      SkIRect subset;
      SkISize dims;
      dims.fWidth = random->nextRangeU(1, 1000);
      dims.fHeight = random->nextRangeU(1, 1000);
      GrSurfaceOrigin origin = random->nextBool() ? kTopLeft_GrSurfaceOrigin
                                                  : kBottomLeft_GrSurfaceOrigin;
      const GrBackendFormat format =
              context->priv().caps()->getDefaultBackendFormat(GrColorType::kRGBA_8888,
                                                              GrRenderable::kNo);
  
      auto proxy = context->priv().proxyProvider()->createProxy(format,
                                                                dims,
                                                                GrRenderable::kNo,
                                                                1,
                                                                GrMipmapped::kNo,
                                                                SkBackingFit::kExact,
                                                                SkBudgeted::kYes,
                                                                GrProtected::kNo);
  
      do {
          if (random->nextBool()) {
              subset.fLeft = random->nextULessThan(dims.fWidth);
              subset.fRight = random->nextRangeU(subset.fLeft + 1, dims.fWidth);
              subset.fTop = random->nextULessThan(dims.fHeight);
              subset.fBottom = random->nextRangeU(subset.fTop + 1, dims.fHeight);
          } else {
              subset.setXYWH(0, 0, dims.fWidth, dims.fHeight);
          }
          // SkCanvas::Lattice allows bounds to be null. However, SkCanvas creates a temp Lattice with
          // a non-null bounds before creating a SkLatticeIter since SkLatticeIter requires a bounds.
          lattice.fBounds = &subset;
          lattice.fXCount = random->nextRangeU(1, subset.width());
          lattice.fYCount = random->nextRangeU(1, subset.height());
          xdivs.reset(new int[lattice.fXCount]);
          ydivs.reset(new int[lattice.fYCount]);
          init_random_divs(xdivs.get(), lattice.fXCount, subset.fLeft, subset.fRight, random);
          init_random_divs(ydivs.get(), lattice.fYCount, subset.fTop, subset.fBottom, random);
          lattice.fXDivs = xdivs.get();
          lattice.fYDivs = ydivs.get();
          bool hasFlags = random->nextBool();
          if (hasFlags) {
              int n = (lattice.fXCount + 1) * (lattice.fYCount + 1);
              flags.reset(new SkCanvas::Lattice::RectType[n]);
              colors.reset(new SkColor[n]);
              for (int i = 0; i < n; ++i) {
                  flags[i] = random->nextBool() ? SkCanvas::Lattice::kTransparent
                                                : SkCanvas::Lattice::kDefault;
              }
              lattice.fRectTypes = flags.get();
              lattice.fColors = colors.get();
          } else {
              lattice.fRectTypes = nullptr;
              lattice.fColors = nullptr;
          }
      } while (!SkLatticeIter::Valid(dims.fWidth, dims.fHeight, lattice));
      SkRect dst;
      dst.fLeft = random->nextRangeScalar(-2000.5f, 1000.f);
      dst.fTop = random->nextRangeScalar(-2000.5f, 1000.f);
      dst.fRight = dst.fLeft + random->nextRangeScalar(0.5f, 1000.f);
      dst.fBottom = dst.fTop + random->nextRangeScalar(0.5f, 1000.f);
      std::unique_ptr<SkLatticeIter> iter(new SkLatticeIter(lattice, dst));
      SkMatrix viewMatrix = GrTest::TestMatrixPreservesRightAngles(random);
      auto csxf = GrTest::TestColorXform(random);
      GrSamplerState::Filter filter =
              random->nextBool() ? GrSamplerState::Filter::kNearest : GrSamplerState::Filter::kLinear;
  
      GrSurfaceProxyView view(
              std::move(proxy), origin,
              context->priv().caps()->getReadSwizzle(format, GrColorType::kRGBA_8888));
  
      return skgpu::v1::LatticeOp::NonAALatticeOp::Make(context, std::move(paint), viewMatrix,
                                                        std::move(view), kPremul_SkAlphaType,
                                                        std::move(csxf), filter, std::move(iter),
                                                        dst);
  }
  
  #endif
  