text: /*
   * Copyright 2017 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  
  #include "tests/Test.h"
  
  #include <array>
  #include <vector>
  #include "include/core/SkBitmap.h"
  #include "include/gpu/GrContext.h"
  #include "include/private/GrResourceKey.h"
  #include "src/core/SkMakeUnique.h"
  #include "src/gpu/GrCaps.h"
  #include "src/gpu/GrContextPriv.h"
  #include "src/gpu/GrGeometryProcessor.h"
  #include "src/gpu/GrImageInfo.h"
  #include "src/gpu/GrMemoryPool.h"
  #include "src/gpu/GrOpFlushState.h"
  #include "src/gpu/GrOpsRenderPass.h"
  #include "src/gpu/GrProgramInfo.h"
  #include "src/gpu/GrRenderTargetContext.h"
  #include "src/gpu/GrRenderTargetContextPriv.h"
  #include "src/gpu/GrResourceProvider.h"
  #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
  #include "src/gpu/glsl/GrGLSLGeometryProcessor.h"
  #include "src/gpu/glsl/GrGLSLVarying.h"
  #include "src/gpu/glsl/GrGLSLVertexGeoBuilder.h"
  
  GR_DECLARE_STATIC_UNIQUE_KEY(gIndexBufferKey);
  
  static constexpr int kBoxSize = 2;
  static constexpr int kBoxCountY = 8;
  static constexpr int kBoxCountX = 8;
  static constexpr int kBoxCount = kBoxCountY * kBoxCountX;
  
  static constexpr int kImageWidth = kBoxCountY * kBoxSize;
  static constexpr int kImageHeight = kBoxCountX * kBoxSize;
  
  static constexpr int kIndexPatternRepeatCount = 3;
  constexpr uint16_t kIndexPattern[6] = {0, 1, 2, 1, 2, 3};
  
  
  class DrawMeshHelper {
  public:
      DrawMeshHelper(GrOpFlushState* state) : fState(state) {}
  
      sk_sp<const GrBuffer> getIndexBuffer();
  
      template<typename T> sk_sp<const GrBuffer> makeVertexBuffer(const SkTArray<T>& data) {
          return this->makeVertexBuffer(data.begin(), data.count());
      }
      template<typename T> sk_sp<const GrBuffer> makeVertexBuffer(const std::vector<T>& data) {
          return this->makeVertexBuffer(data.data(), data.size());
      }
      template<typename T> sk_sp<const GrBuffer> makeVertexBuffer(const T* data, int count);
  
      sk_sp<const GrBuffer> fVertBuffer;
      sk_sp<const GrBuffer> fVertBuffer2;
      sk_sp<const GrBuffer> fIndexBuffer;
      sk_sp<const GrBuffer> fInstBuffer;
  
      void drawMesh(const GrMesh& mesh);
  
  private:
      GrOpFlushState* fState;
  };
  
  struct Box {
      float fX, fY;
      GrColor fColor;
  };
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  
  /**
   * This is a GPU-backend specific test. It tries to test all possible usecases of GrMesh. The test
   * works by drawing checkerboards of colored boxes, reading back the pixels, and comparing with
   * expected results. The boxes are drawn on integer boundaries and the (opaque) colors are chosen
   * from the set (r,g,b) = (0,255)^3, so the GPU renderings ought to produce exact matches.
   */
  
  static void run_test(GrContext* context, const char* testName, skiatest::Reporter*,
                       const std::unique_ptr<GrRenderTargetContext>&, const SkBitmap& gold,
                       std::function<void(DrawMeshHelper*)> prepareFn,
                       std::function<void(DrawMeshHelper*)> executeFn);
  
  DEF_GPUTEST_FOR_RENDERING_CONTEXTS(GrMeshTest, reporter, ctxInfo) {
      GrContext* context = ctxInfo.grContext();
  
      auto rtc = context->priv().makeDeferredRenderTargetContext(
              SkBackingFit::kExact, kImageWidth, kImageHeight, GrColorType::kRGBA_8888, nullptr);
      if (!rtc) {
          ERRORF(reporter, "could not create render target context.");
          return;
      }
  
      SkTArray<Box> boxes;
      SkTArray<std::array<Box, 4>> vertexData;
      SkBitmap gold;
  
      // ---- setup ----------
  
      SkPaint paint;
      paint.setBlendMode(SkBlendMode::kSrc);
      gold.allocN32Pixels(kImageWidth, kImageHeight);
  
      SkCanvas goldCanvas(gold);
  
      for (int y = 0; y < kBoxCountY; ++y) {
          for (int x = 0; x < kBoxCountX; ++x) {
              int c = y + x;
              int rgb[3] = {-(c & 1) & 0xff, -((c >> 1) & 1) & 0xff, -((c >> 2) & 1) & 0xff};
  
              const Box box = boxes.push_back() = {
                      float(x * kBoxSize),
                      float(y * kBoxSize),
                      GrColorPackRGBA(rgb[0], rgb[1], rgb[2], 255)
              };
  
              std::array<Box, 4>& boxVertices = vertexData.push_back();
              for (int i = 0; i < 4; ++i) {
                  boxVertices[i] = {
                          box.fX + (i / 2) * kBoxSize,
                          box.fY + (i % 2) * kBoxSize,
                          box.fColor
                  };
              }
  
              paint.setARGB(255, rgb[0], rgb[1], rgb[2]);
              goldCanvas.drawRect(SkRect::MakeXYWH(box.fX, box.fY, kBoxSize, kBoxSize), paint);
          }
      }
  
      // ---- tests ----------
  
  #define VALIDATE(buff)                           \
      do {                                         \
          if (!buff) {                             \
              ERRORF(reporter, #buff " is null."); \
              return;                              \
          }                                        \
      } while (0)
  
      run_test(context, "setNonIndexedNonInstanced", reporter, rtc, gold,
               [&](DrawMeshHelper* helper) {
                   SkTArray<Box> expandedVertexData;
                   for (int i = 0; i < kBoxCount; ++i) {
                       for (int j = 0; j < 6; ++j) {
                           expandedVertexData.push_back(vertexData[i][kIndexPattern[j]]);
                       }
                   }
  
                   // Draw boxes one line at a time to exercise base vertex.
                   helper->fVertBuffer = helper->makeVertexBuffer(expandedVertexData);
                   VALIDATE(helper->fVertBuffer);
               },
               [&](DrawMeshHelper* helper) {
                   for (int y = 0; y < kBoxCountY; ++y) {
                       GrMesh mesh(GrPrimitiveType::kTriangles);
                       mesh.setNonIndexedNonInstanced(kBoxCountX * 6);
                       mesh.setVertexData(helper->fVertBuffer, y * kBoxCountX * 6);
                       helper->drawMesh(mesh);
                   }
               });
  
      run_test(context, "setIndexed", reporter, rtc, gold,
               [&](DrawMeshHelper* helper) {
                  helper->fIndexBuffer = helper->getIndexBuffer();
                  VALIDATE(helper->fIndexBuffer);
                  helper->fVertBuffer = helper->makeVertexBuffer(vertexData);
                  VALIDATE(helper->fVertBuffer);
               },
               [&](DrawMeshHelper* helper) {
                  int baseRepetition = 0;
                  int i = 0;
                  // Start at various repetitions within the patterned index buffer to exercise base
                  // index.
                  while (i < kBoxCount) {
                      GR_STATIC_ASSERT(kIndexPatternRepeatCount >= 3);
                      int repetitionCount = SkTMin(3 - baseRepetition, kBoxCount - i);
  
                      GrMesh mesh(GrPrimitiveType::kTriangles);
                      mesh.setIndexed(helper->fIndexBuffer, repetitionCount * 6, baseRepetition * 6,
                                      baseRepetition * 4, (baseRepetition + repetitionCount) * 4 - 1,
                                      GrPrimitiveRestart::kNo);
                      mesh.setVertexData(helper->fVertBuffer, (i - baseRepetition) * 4);
                      helper->drawMesh(mesh);
  
                      baseRepetition = (baseRepetition + 1) % 3;
                      i += repetitionCount;
                  }
              });
  
      run_test(context, "setIndexedPatterned", reporter, rtc, gold,
               [&](DrawMeshHelper* helper) {
                   helper->fIndexBuffer = helper->getIndexBuffer();
                   VALIDATE(helper->fIndexBuffer);
                   helper->fVertBuffer = helper->makeVertexBuffer(vertexData);
                   VALIDATE(helper->fVertBuffer);
               },
               [&](DrawMeshHelper* helper) {
                  // Draw boxes one line at a time to exercise base vertex. setIndexedPatterned does
                  // not support a base index.
                  for (int y = 0; y < kBoxCountY; ++y) {
                      GrMesh mesh(GrPrimitiveType::kTriangles);
                      mesh.setIndexedPatterned(helper->fIndexBuffer, 6, 4, kBoxCountX,
                                               kIndexPatternRepeatCount);
                      mesh.setVertexData(helper->fVertBuffer, y * kBoxCountX * 4);
                      helper->drawMesh(mesh);
                  }
               });
  
      for (bool indexed : {false, true}) {
          if (!context->priv().caps()->instanceAttribSupport()) {
              break;
          }
  
          run_test(context, indexed ? "setIndexedInstanced" : "setInstanced",
                   reporter, rtc, gold,
                   [&](DrawMeshHelper* helper) {
                       helper->fIndexBuffer = indexed ? helper->getIndexBuffer() : nullptr;
                       helper->fInstBuffer = helper->makeVertexBuffer(boxes);
                       VALIDATE(helper->fInstBuffer);
                       helper->fVertBuffer =
                               helper->makeVertexBuffer(std::vector<float>{0,0, 0,1, 1,0, 1,1});
                       VALIDATE(helper->fVertBuffer);
                       helper->fVertBuffer2 = helper->makeVertexBuffer( // for testing base vertex.
                           std::vector<float>{-1,-1, -1,-1, 0,0, 0,1, 1,0, 1,1});
                       VALIDATE(helper->fVertBuffer2);
                   },
                   [&](DrawMeshHelper* helper) {
                       // Draw boxes one line at a time to exercise base instance, base vertex, and
                       // null vertex buffer. setIndexedInstanced intentionally does not support a
                       // base index.
                       for (int y = 0; y < kBoxCountY; ++y) {
                           GrMesh mesh(indexed ? GrPrimitiveType::kTriangles
                                       : GrPrimitiveType::kTriangleStrip);
                           if (indexed) {
                               VALIDATE(helper->fIndexBuffer);
                               mesh.setIndexedInstanced(helper->fIndexBuffer, 6, helper->fInstBuffer,
                                                        kBoxCountX, y * kBoxCountX,
                                                        GrPrimitiveRestart::kNo);
                           } else {
                               mesh.setInstanced(helper->fInstBuffer, kBoxCountX, y * kBoxCountX, 4);
                           }
                           switch (y % 3) {
                               case 0:
                                   if (context->priv().caps()->shaderCaps()->vertexIDSupport()) {
                                       if (y % 2) {
                                           // We don't need this call because it's the initial state
                                           // of GrMesh.
                                           mesh.setVertexData(nullptr);
                                       }
                                       break;
                                   }
                                   // Fallthru.
                               case 1:
                                   mesh.setVertexData(helper->fVertBuffer);
                                   break;
                               case 2:
                                   mesh.setVertexData(helper->fVertBuffer2, 2);
                                   break;
                           }
                           helper->drawMesh(mesh);
                       }
                   });
      }
  }
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  
  class GrMeshTestOp : public GrDrawOp {
  public:
      DEFINE_OP_CLASS_ID
  
      static std::unique_ptr<GrDrawOp> Make(GrContext* context,
                                            std::function<void(DrawMeshHelper*)> prepareFn,
                                            std::function<void(DrawMeshHelper*)> executeFn) {
          GrOpMemoryPool* pool = context->priv().opMemoryPool();
  
          return pool->allocate<GrMeshTestOp>(prepareFn, executeFn);
      }
  
  private:
      friend class GrOpMemoryPool; // for ctor
  
      GrMeshTestOp(std::function<void(DrawMeshHelper*)> prepareFn,
                   std::function<void(DrawMeshHelper*)> executeFn)
          : INHERITED(ClassID())
          , fPrepareFn(prepareFn)
          , fExecuteFn(executeFn){
          this->setBounds(SkRect::MakeIWH(kImageWidth, kImageHeight),
                          HasAABloat::kNo, IsHairline::kNo);
      }
  
      const char* name() const override { return "GrMeshTestOp"; }
      FixedFunctionFlags fixedFunctionFlags() const override { return FixedFunctionFlags::kNone; }
      GrProcessorSet::Analysis finalize(const GrCaps&, const GrAppliedClip*,
                                        bool hasMixedSampledCoverage, GrClampType) override {
          return GrProcessorSet::EmptySetAnalysis();
      }
      void onPrepare(GrOpFlushState* state) override {
          fHelper.reset(new DrawMeshHelper(state));
          fPrepareFn(fHelper.get());
      }
      void onExecute(GrOpFlushState* state, const SkRect& chainBounds) override {
          fExecuteFn(fHelper.get());
      }
  
      std::unique_ptr<DrawMeshHelper> fHelper;
      std::function<void(DrawMeshHelper*)> fPrepareFn;
      std::function<void(DrawMeshHelper*)> fExecuteFn;
  
      typedef GrDrawOp INHERITED;
  };
  
  class GrMeshTestProcessor : public GrGeometryProcessor {
  public:
      GrMeshTestProcessor(bool instanced, bool hasVertexBuffer)
              : INHERITED(kGrMeshTestProcessor_ClassID) {
          if (instanced) {
              fInstanceLocation = {"location", kFloat2_GrVertexAttribType, kHalf2_GrSLType};
              fInstanceColor = {"color", kUByte4_norm_GrVertexAttribType, kHalf4_GrSLType};
              this->setInstanceAttributes(&fInstanceLocation, 2);
              if (hasVertexBuffer) {
                  fVertexPosition = {"vertex", kFloat2_GrVertexAttribType, kHalf2_GrSLType};
                  this->setVertexAttributes(&fVertexPosition, 1);
              }
          } else {
              fVertexPosition = {"vertex", kFloat2_GrVertexAttribType, kHalf2_GrSLType};
              fVertexColor = {"color", kUByte4_norm_GrVertexAttribType, kHalf4_GrSLType};
              this->setVertexAttributes(&fVertexPosition, 2);
          }
      }
  
      const char* name() const override { return "GrMeshTest Processor"; }
  
      const Attribute& inColor() const {
          return fVertexColor.isInitialized() ? fVertexColor : fInstanceColor;
      }
  
      void getGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder* b) const final {
          b->add32(fInstanceLocation.isInitialized());
          b->add32(fVertexPosition.isInitialized());
      }
  
      GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const final;
  
  private:
      Attribute fVertexPosition;
      Attribute fVertexColor;
  
      Attribute fInstanceLocation;
      Attribute fInstanceColor;
  
      friend class GLSLMeshTestProcessor;
      typedef GrGeometryProcessor INHERITED;
  };
  
  class GLSLMeshTestProcessor : public GrGLSLGeometryProcessor {
      void setData(const GrGLSLProgramDataManager& pdman, const GrPrimitiveProcessor&,
                   FPCoordTransformIter&& transformIter) final {}
  
      void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) final {
          const GrMeshTestProcessor& mp = args.fGP.cast<GrMeshTestProcessor>();
  
          GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
          varyingHandler->emitAttributes(mp);
          varyingHandler->addPassThroughAttribute(mp.inColor(), args.fOutputColor);
  
          GrGLSLVertexBuilder* v = args.fVertBuilder;
          if (!mp.fInstanceLocation.isInitialized()) {
              v->codeAppendf("float2 vertex = %s;", mp.fVertexPosition.name());
          } else {
              if (mp.fVertexPosition.isInitialized()) {
                  v->codeAppendf("float2 offset = %s;", mp.fVertexPosition.name());
              } else {
                  v->codeAppend ("float2 offset = float2(sk_VertexID / 2, sk_VertexID % 2);");
              }
              v->codeAppendf("float2 vertex = %s + offset * %i;", mp.fInstanceLocation.name(),
                             kBoxSize);
          }
          gpArgs->fPositionVar.set(kFloat2_GrSLType, "vertex");
  
          GrGLSLFPFragmentBuilder* f = args.fFragBuilder;
          f->codeAppendf("%s = half4(1);", args.fOutputCoverage);
      }
  };
  
  GrGLSLPrimitiveProcessor* GrMeshTestProcessor::createGLSLInstance(const GrShaderCaps&) const {
      return new GLSLMeshTestProcessor;
  }
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  
  template<typename T>
  sk_sp<const GrBuffer> DrawMeshHelper::makeVertexBuffer(const T* data, int count) {
      return sk_sp<const GrBuffer>(fState->resourceProvider()->createBuffer(
              count * sizeof(T), GrGpuBufferType::kVertex, kDynamic_GrAccessPattern, data));
  }
  
  sk_sp<const GrBuffer> DrawMeshHelper::getIndexBuffer() {
      GR_DEFINE_STATIC_UNIQUE_KEY(gIndexBufferKey);
      return fState->resourceProvider()->findOrCreatePatternedIndexBuffer(
              kIndexPattern, 6, kIndexPatternRepeatCount, 4, gIndexBufferKey);
  }
  
  void DrawMeshHelper::drawMesh(const GrMesh& mesh) {
      GrPipeline pipeline(GrScissorTest::kDisabled, SkBlendMode::kSrc, GrSwizzle::RGBA());
      GrMeshTestProcessor mtp(mesh.isInstanced(), mesh.hasVertexData());
  
      GrProgramInfo programInfo(fState->drawOpArgs().numSamples(),
                                fState->drawOpArgs().origin(),
                                pipeline,
                                mtp,
                                nullptr, nullptr, 0);
  
      fState->opsRenderPass()->draw(programInfo, &mesh, 1,
                                    SkRect::MakeIWH(kImageWidth, kImageHeight));
  }
  
  static void run_test(GrContext* context, const char* testName, skiatest::Reporter* reporter,
                       const std::unique_ptr<GrRenderTargetContext>& rtc, const SkBitmap& gold,
                       std::function<void(DrawMeshHelper*)> prepareFn,
                       std::function<void(DrawMeshHelper*)> executeFn) {
      const int w = gold.width(), h = gold.height(), rowBytes = gold.rowBytes();
      const uint32_t* goldPx = reinterpret_cast<const uint32_t*>(gold.getPixels());
      if (h != rtc->height() || w != rtc->width()) {
          ERRORF(reporter, "[%s] expectation and rtc not compatible (?).", testName);
          return;
      }
      if (sizeof(uint32_t) * kImageWidth != gold.rowBytes()) {
          ERRORF(reporter, "unexpected row bytes in gold image.", testName);
          return;
      }
  
      SkAutoSTMalloc<kImageHeight * kImageWidth, uint32_t> resultPx(h * rowBytes);
      rtc->clear(nullptr, SkPMColor4f::FromBytes_RGBA(0xbaaaaaad),
                 GrRenderTargetContext::CanClearFullscreen::kYes);
      rtc->priv().testingOnly_addDrawOp(GrMeshTestOp::Make(context, prepareFn, executeFn));
      rtc->readPixels(gold.info(), resultPx, rowBytes, {0, 0});
      for (int y = 0; y < h; ++y) {
          for (int x = 0; x < w; ++x) {
              uint32_t expected = goldPx[y * kImageWidth + x];
              uint32_t actual = resultPx[y * kImageWidth + x];
              if (expected != actual) {
                  ERRORF(reporter, "[%s] pixel (%i,%i): got 0x%x expected 0x%x",
                         testName, x, y, actual, expected);
                  return;
              }
          }
      }
  }
  