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1 /*
2  * Copyright 2018 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 QuadPerEdgeAA_DEFINED
9 #define QuadPerEdgeAA_DEFINED
10 
11 #include "include/core/SkPoint.h"
12 #include "include/core/SkPoint3.h"
13 #include "include/private/GrTypesPriv.h"
14 #include "src/gpu/BufferWriter.h"
15 #include "src/gpu/GrColor.h"
16 #include "src/gpu/GrGeometryProcessor.h"
17 #include "src/gpu/GrSamplerState.h"
18 #include "src/gpu/geometry/GrQuad.h"
19 #include "src/gpu/geometry/GrQuadUtils.h"
20 #include "src/gpu/ops/TextureOp.h"
21 
22 class GrCaps;
23 class GrColorSpaceXform;
24 class GrMeshDrawTarget;
25 class GrShaderCaps;
26 struct VertexWriter;
27 
28 namespace skgpu::v1::QuadPerEdgeAA {
29     using Saturate = skgpu::v1::TextureOp::Saturate;
30 
31     enum class CoverageMode { kNone, kWithPosition, kWithColor };
32     enum class Subset : bool { kNo = false, kYes = true };
33     enum class ColorType { kNone, kByte, kFloat, kLast = kFloat };
34     static const int kColorTypeCount = static_cast<int>(ColorType::kLast) + 1;
35 
36     enum class IndexBufferOption {
37         kPictureFramed,    // geometrically AA'd   -> 8 verts/quad + an index buffer
38         kIndexedRects,     // non-AA'd but indexed -> 4 verts/quad + an index buffer
39         kTriStrips,        // non-AA'd             -> 4 verts/quad but no index buffer
40         kLast = kTriStrips
41     };
42     static const int kIndexBufferOptionCount = static_cast<int>(IndexBufferOption::kLast) + 1;
43 
44     IndexBufferOption CalcIndexBufferOption(GrAAType aa, int numQuads);
45 
46     // Gets the minimum ColorType that can represent a color.
47     ColorType MinColorType(SkPMColor4f);
48 
49     // Specifies the vertex configuration for an op that renders per-edge AA quads. The vertex
50     // order (when enabled) is device position, color, local position, subset, aa edge equations.
51     // This order matches the constructor argument order of VertexSpec and is the order that
52     // GPAttributes maintains. If hasLocalCoords is false, then the local quad type can be ignored.
53     struct VertexSpec {
54     public:
VertexSpecVertexSpec55         VertexSpec()
56                 : fDeviceQuadType(0)     // kAxisAligned
57                 , fLocalQuadType(0)      // kAxisAligned
58                 , fIndexBufferOption(0)  // kPictureFramed
59                 , fHasLocalCoords(false)
60                 , fColorType(0)          // kNone
61                 , fHasSubset(false)
62                 , fUsesCoverageAA(false)
63                 , fCompatibleWithCoverageAsAlpha(false)
64                 , fRequiresGeometrySubset(false) {}
65 
VertexSpecVertexSpec66         VertexSpec(GrQuad::Type deviceQuadType, ColorType colorType, GrQuad::Type localQuadType,
67                    bool hasLocalCoords,
68                    Subset subset, GrAAType aa, bool coverageAsAlpha,
69                    IndexBufferOption indexBufferOption)
70                 : fDeviceQuadType(static_cast<unsigned>(deviceQuadType))
71                 , fLocalQuadType(static_cast<unsigned>(localQuadType))
72                 , fIndexBufferOption(static_cast<unsigned>(indexBufferOption))
73                 , fHasLocalCoords(hasLocalCoords)
74                 , fColorType(static_cast<unsigned>(colorType))
75                 , fHasSubset(static_cast<unsigned>(subset))
76                 , fUsesCoverageAA(aa == GrAAType::kCoverage)
77                 , fCompatibleWithCoverageAsAlpha(coverageAsAlpha)
78                 , fRequiresGeometrySubset(aa == GrAAType::kCoverage &&
79                                           deviceQuadType > GrQuad::Type::kRectilinear) { }
80 
deviceQuadTypeVertexSpec81         GrQuad::Type deviceQuadType() const { return static_cast<GrQuad::Type>(fDeviceQuadType); }
localQuadTypeVertexSpec82         GrQuad::Type localQuadType() const { return static_cast<GrQuad::Type>(fLocalQuadType); }
indexBufferOptionVertexSpec83         IndexBufferOption indexBufferOption() const {
84             return static_cast<IndexBufferOption>(fIndexBufferOption);
85         }
hasLocalCoordsVertexSpec86         bool hasLocalCoords() const { return fHasLocalCoords; }
colorTypeVertexSpec87         ColorType colorType() const { return static_cast<ColorType>(fColorType); }
hasVertexColorsVertexSpec88         bool hasVertexColors() const { return ColorType::kNone != this->colorType(); }
hasSubsetVertexSpec89         bool hasSubset() const { return fHasSubset; }
usesCoverageAAVertexSpec90         bool usesCoverageAA() const { return fUsesCoverageAA; }
compatibleWithCoverageAsAlphaVertexSpec91         bool compatibleWithCoverageAsAlpha() const { return fCompatibleWithCoverageAsAlpha; }
requiresGeometrySubsetVertexSpec92         bool requiresGeometrySubset() const { return fRequiresGeometrySubset; }
93         // Will always be 2 or 3
94         int deviceDimensionality() const;
95         // Will always be 0 if hasLocalCoords is false, otherwise will be 2 or 3
96         int localDimensionality() const;
97 
verticesPerQuadVertexSpec98         int verticesPerQuad() const { return fUsesCoverageAA ? 8 : 4; }
99 
100         CoverageMode coverageMode() const;
101         size_t vertexSize() const;
102 
needsIndexBufferVertexSpec103         bool needsIndexBuffer() const { return this->indexBufferOption() !=
104                                                IndexBufferOption::kTriStrips; }
105 
primitiveTypeVertexSpec106         GrPrimitiveType primitiveType() const {
107             switch (this->indexBufferOption()) {
108                 case IndexBufferOption::kPictureFramed: return GrPrimitiveType::kTriangles;
109                 case IndexBufferOption::kIndexedRects:  return GrPrimitiveType::kTriangles;
110                 case IndexBufferOption::kTriStrips:     return GrPrimitiveType::kTriangleStrip;
111             }
112 
113             SkUNREACHABLE;
114         }
115 
116     private:
117         static_assert(GrQuad::kTypeCount <= 4, "GrQuad::Type doesn't fit in 2 bits");
118         static_assert(kColorTypeCount <= 4, "Color doesn't fit in 2 bits");
119         static_assert(kIndexBufferOptionCount <= 4, "IndexBufferOption doesn't fit in 2 bits");
120 
121         unsigned fDeviceQuadType: 2;
122         unsigned fLocalQuadType: 2;
123         unsigned fIndexBufferOption: 2;
124         unsigned fHasLocalCoords: 1;
125         unsigned fColorType : 2;
126         unsigned fHasSubset : 1;
127         unsigned fUsesCoverageAA: 1;
128         unsigned fCompatibleWithCoverageAsAlpha: 1;
129         // The geometry subset serves to clip off pixels touched by quads with sharp corners that
130         // would otherwise exceed the miter limit for the AA-outset geometry.
131         unsigned fRequiresGeometrySubset : 1;
132     };
133 
134     // A Tessellator is responsible for processing a series of device+local GrQuads into a VBO,
135     // as specified by a VertexSpec. This vertex data can then be processed by a GP created with
136     // MakeProcessor and/or MakeTexturedProcessor.
137     class Tessellator {
138     public:
139         explicit Tessellator(const VertexSpec& spec, char* vertices);
140 
141         // Calculates (as needed) inset and outset geometry for anti-aliasing, and appends all
142         // necessary position and vertex attributes required by this Tessellator's VertexSpec into
143         // the 'vertices' the Tessellator was called with. The insetting and outsetting may
144         // damage the provided GrQuads (as this is intended to work with GrQuadBuffer::Iter).
145         // 'localQuad' can be null if the VertexSpec does not use local coords.
146         void append(GrQuad* deviceQuad, GrQuad* localQuad,
147                     const SkPMColor4f& color, const SkRect& uvSubset, GrQuadAAFlags aaFlags);
148 
149         SkDEBUGCODE(char* vertices() const { return (char*) fVertexWriter.ptr(); })
150 
151     private:
152         // VertexSpec defines many unique ways to write vertex attributes, which can be handled
153         // generically by branching per-quad based on the VertexSpec. However, there are several
154         // specs that appear in the wild far more frequently, so they use explicit WriteQuadProcs
155         // that have no branches.
156         typedef void (*WriteQuadProc)(VertexWriter* vertices, const VertexSpec& spec,
157                                       const GrQuad* deviceQuad, const GrQuad* localQuad,
158                                       const float coverage[4], const SkPMColor4f& color,
159                                       const SkRect& geomSubset, const SkRect& texSubset);
160         static WriteQuadProc GetWriteQuadProc(const VertexSpec& spec);
161 
162         GrQuadUtils::TessellationHelper fAAHelper;
163         VertexSpec                      fVertexSpec;
164         VertexWriter                    fVertexWriter;
165         WriteQuadProc                   fWriteProc;
166     };
167 
168     GrGeometryProcessor* MakeProcessor(SkArenaAlloc*, const VertexSpec&);
169 
170     GrGeometryProcessor* MakeTexturedProcessor(SkArenaAlloc*,
171                                                const VertexSpec&,
172                                                const GrShaderCaps&,
173                                                const GrBackendFormat&,
174                                                GrSamplerState,
175                                                const GrSwizzle&,
176                                                sk_sp<GrColorSpaceXform> textureColorSpaceXform,
177                                                Saturate);
178 
179     // This method will return the correct index buffer for the specified indexBufferOption.
180     // It will, correctly, return nullptr if the indexBufferOption is kTriStrips.
181     sk_sp<const GrBuffer> GetIndexBuffer(GrMeshDrawTarget*, IndexBufferOption);
182 
183     // What is the maximum number of quads allowed for the specified indexBuffer option?
184     int QuadLimit(IndexBufferOption);
185 
186     // This method will issue the draw call on the provided GrOpsRenderPass, as specified by the
187     // indexing method in vertexSpec. It is up to the calling code to allocate, fill in, and bind a
188     // vertex buffer, and to acquire and bind the correct index buffer (if needed) with
189     // GrPrimitiveRestart::kNo.
190     //
191     // @param runningQuadCount  the number of quads already stored in 'vertexBuffer' and
192     //                          'indexBuffer' e.g., different GrMeshes have already been placed in
193     //                          the buffers to allow dynamic state changes.
194     // @param quadCount         the number of quads that will be drawn by the provided 'mesh'.
195     //                          A subsequent ConfigureMesh call would the use
196     //                          'runningQuadCount' + 'quadCount' for its new 'runningQuadCount'.
197     void IssueDraw(const GrCaps&, GrOpsRenderPass*, const VertexSpec&, int runningQuadCount,
198                    int quadCount, int maxVerts, int absVertBufferOffset);
199 
200 } // namespace skgpu::v1::QuadPerEdgeAA
201 
202 #endif // QuadPerEdgeAA_DEFINED
203