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      1 /*
      2  * Copyright 2017 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef GrCCPRPathProcessor_DEFINED
      9 #define GrCCPRPathProcessor_DEFINED
     10 
     11 #include "GrGeometryProcessor.h"
     12 #include "SkPath.h"
     13 #include <array>
     14 
     15 class GrOnFlushResourceProvider;
     16 class GrShaderCaps;
     17 
     18 /**
     19  * This class draws AA paths using the coverage count masks produced by GrCCPRCoverageProcessor.
     20  *
     21  * Paths are drawn as bloated octagons, and coverage is derived from the coverage count mask and
     22  * fill rule.
     23  *
     24  * The caller must set up an instance buffer as detailed below, then draw indexed-instanced
     25  * triangles using the index and vertex buffers provided by this class.
     26  */
     27 class GrCCPRPathProcessor : public GrGeometryProcessor {
     28 public:
     29     static constexpr int kPerInstanceIndexCount = 6 * 3;
     30     static sk_sp<GrBuffer> FindOrMakeIndexBuffer(GrOnFlushResourceProvider*);
     31     static sk_sp<GrBuffer> FindOrMakeVertexBuffer(GrOnFlushResourceProvider*);
     32 
     33     enum class InstanceAttribs {
     34         kDevBounds,
     35         kDevBounds45,
     36         kViewMatrix, // FIXME: This causes a lot of duplication. It could move to a texel buffer.
     37         kViewTranslate,
     38         kAtlasOffset,
     39         kColor
     40     };
     41     static constexpr int kNumInstanceAttribs = 1 + (int)InstanceAttribs::kColor;
     42 
     43     struct Instance {
     44         SkRect                   fDevBounds;
     45         SkRect                   fDevBounds45; // Bounding box in "| 1  -1 | * devCoords" space.
     46                                                //                  | 1   1 |
     47         std::array<float, 4>     fViewMatrix;  // {kScaleX, kSkewy, kSkewX, kScaleY}
     48         std::array<float, 2>     fViewTranslate;
     49         std::array<int32_t, 2>   fAtlasOffset;
     50         uint32_t                 fColor;
     51 
     52         GR_STATIC_ASSERT(SK_SCALAR_IS_FLOAT);
     53     };
     54 
     55     GR_STATIC_ASSERT(4 * 17 == sizeof(Instance)); // FIXME: 4 * 16 by making fAtlasOffset int16_t's.
     56 
     57     GrCCPRPathProcessor(GrResourceProvider*, sk_sp<GrTextureProxy> atlas, SkPath::FillType,
     58                        const GrShaderCaps&);
     59 
     60     const char* name() const override { return "GrCCPRPathProcessor"; }
     61     const GrTexture* atlas() const { return fAtlasAccess.peekTexture(); }
     62     SkPath::FillType fillType() const { return fFillType; }
     63     const Attribute& getInstanceAttrib(InstanceAttribs attribID) const {
     64         const Attribute& attrib = this->getAttrib((int)attribID);
     65         SkASSERT(Attribute::InputRate::kPerInstance == attrib.fInputRate);
     66         return attrib;
     67     }
     68     const Attribute& getEdgeNormsAttrib() const {
     69         SkASSERT(1 + kNumInstanceAttribs == this->numAttribs());
     70         const Attribute& attrib = this->getAttrib(kNumInstanceAttribs);
     71         SkASSERT(Attribute::InputRate::kPerVertex == attrib.fInputRate);
     72         return attrib;
     73     }
     74 
     75     void getGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override;
     76     GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const override;
     77 
     78 private:
     79     const SkPath::FillType   fFillType;
     80     TextureSampler           fAtlasAccess;
     81 
     82     typedef GrGeometryProcessor INHERITED;
     83 };
     84 
     85 #endif
     86