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 GrCCPathProcessor_DEFINED
9#define GrCCPathProcessor_DEFINED
10
11#include "GrCaps.h"
12#include "GrGeometryProcessor.h"
13#include "SkPath.h"
14#include <array>
15
16class GrOnFlushResourceProvider;
17
18/**
19 * This class draws AA paths using the coverage count masks produced by GrCCCoverageProcessor.
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 * meshes using the buffers and parameters provided by this class.
26 */
27class GrCCPathProcessor : public GrGeometryProcessor {
28public:
29    enum class InstanceAttribs {
30        kDevBounds,
31        kDevBounds45,
32        kViewMatrix, // FIXME: This causes a lot of duplication. It could move to a texel buffer.
33        kViewTranslate,
34        kAtlasOffset,
35        kColor
36    };
37    static constexpr int kNumInstanceAttribs = 1 + (int)InstanceAttribs::kColor;
38
39    struct Instance {
40        SkRect fDevBounds;
41        SkRect fDevBounds45; // Bounding box in "| 1  -1 | * devCoords" space.
42                             //                  | 1   1 |
43        std::array<float, 4> fViewMatrix;  // {kScaleX, kSkewy, kSkewX, kScaleY}
44        std::array<float, 2> fViewTranslate;
45        std::array<int16_t, 2> fAtlasOffset;
46        uint32_t fColor;
47
48        GR_STATIC_ASSERT(SK_SCALAR_IS_FLOAT);
49    };
50
51    GR_STATIC_ASSERT(4 * 16 == sizeof(Instance));
52
53    static GrPrimitiveType MeshPrimitiveType(const GrCaps& caps) {
54        return caps.usePrimitiveRestart() ? GrPrimitiveType::kTriangleStrip
55                                          : GrPrimitiveType::kTriangles;
56    }
57    static sk_sp<const GrBuffer> FindVertexBuffer(GrOnFlushResourceProvider*);
58    static sk_sp<const GrBuffer> FindIndexBuffer(GrOnFlushResourceProvider*);
59    static int NumIndicesPerInstance(const GrCaps&);
60
61    GrCCPathProcessor(GrResourceProvider*, sk_sp<GrTextureProxy> atlas, SkPath::FillType);
62
63    const char* name() const override { return "GrCCPathProcessor"; }
64    const GrSurfaceProxy* atlasProxy() const { return fAtlasAccess.proxy(); }
65    const GrTexture* atlas() const { return fAtlasAccess.peekTexture(); }
66    SkPath::FillType fillType() const { return fFillType; }
67    const Attribute& getInstanceAttrib(InstanceAttribs attribID) const {
68        const Attribute& attrib = this->getAttrib((int)attribID);
69        SkASSERT(Attribute::InputRate::kPerInstance == attrib.fInputRate);
70        return attrib;
71    }
72    const Attribute& getEdgeNormsAttrib() const {
73        SkASSERT(1 + kNumInstanceAttribs == this->numAttribs());
74        const Attribute& attrib = this->getAttrib(kNumInstanceAttribs);
75        SkASSERT(Attribute::InputRate::kPerVertex == attrib.fInputRate);
76        return attrib;
77    }
78
79    void getGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override;
80    GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const override;
81
82private:
83    const SkPath::FillType fFillType;
84    const TextureSampler fAtlasAccess;
85
86    typedef GrGeometryProcessor INHERITED;
87};
88
89#endif
90