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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 
name()60     const char* name() const override { return "GrCCPRPathProcessor"; }
atlas()61     const GrTexture* atlas() const { return fAtlasAccess.peekTexture(); }
fillType()62     SkPath::FillType fillType() const { return fFillType; }
getInstanceAttrib(InstanceAttribs attribID)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     }
getEdgeNormsAttrib()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