1/*
2 * Copyright 2013 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 GrGLSLGeometryProcessor_DEFINED
9#define GrGLSLGeometryProcessor_DEFINED
10
11#include "src/gpu/glsl/GrGLSLPrimitiveProcessor.h"
12
13class GrGLSLGPBuilder;
14
15/**
16 * If a GL effect needs a GrGLFullShaderBuilder* object to emit vertex code, then it must inherit
17 * from this class. Since paths don't have vertices, this class is only meant to be used internally
18 * by skia, for special cases.
19 */
20class GrGLSLGeometryProcessor : public GrGLSLPrimitiveProcessor {
21public:
22 /* Any general emit code goes in the base class emitCode. Subclasses override onEmitCode */
23 void emitCode(EmitArgs&) final;
24
25protected:
26 // A helper which subclasses can use to upload coord transform matrices in setData().
27 void setTransformDataHelper(const SkMatrix& localMatrix,
28 const GrGLSLProgramDataManager& pdman,
29 const CoordTransformRange&);
30
31 // Emit transformed local coords from the vertex shader as a uniform matrix and varying per
32 // coord-transform. localCoordsVar must be a 2- or 3-component vector. If it is 3 then it is
33 // assumed to be a 2D homogeneous coordinate.
34 void emitTransforms(GrGLSLVertexBuilder*,
35 GrGLSLVaryingHandler*,
36 GrGLSLUniformHandler*,
37 const GrShaderVar& localCoordsVar,
38 const SkMatrix& localMatrix,
39 FPCoordTransformHandler*);
40
41 // Version of above that assumes identity for the local matrix.
42 void emitTransforms(GrGLSLVertexBuilder* vb,
43 GrGLSLVaryingHandler* varyingHandler,
44 GrGLSLUniformHandler* uniformHandler,
45 const GrShaderVar& localCoordsVar,
46 FPCoordTransformHandler* handler) {
47 this->emitTransforms(vb, varyingHandler, uniformHandler, localCoordsVar, SkMatrix::I(),
48 handler);
49 }
50
51 struct GrGPArgs {
52 // Used to specify the output variable used by the GP to store its device position. It can
53 // either be a float2 or a float3 (in order to handle perspective). The subclass sets this
54 // in its onEmitCode().
55 GrShaderVar fPositionVar;
56 };
57
58 // Helpers for adding code to write the transformed vertex position. The first simple version
59 // just writes a variable named by 'posName' into the position output variable with the
60 // assumption that the position is 2D. The second version transforms the input position by a
61 // view matrix and the output variable is 2D or 3D depending on whether the view matrix is
62 // perspective. Both versions declare the output position variable and will set
63 // GrGPArgs::fPositionVar.
64 void writeOutputPosition(GrGLSLVertexBuilder*, GrGPArgs*, const char* posName);
65 void writeOutputPosition(GrGLSLVertexBuilder*,
66 GrGLSLUniformHandler* uniformHandler,
67 GrGPArgs*,
68 const char* posName,
69 const SkMatrix& mat,
70 UniformHandle* viewMatrixUniform);
71
72 static uint32_t ComputePosKey(const SkMatrix& mat) {
73 if (mat.isIdentity()) {
74 return 0x0;
75 } else if (!mat.hasPerspective()) {
76 return 0x01;
77 } else {
78 return 0x02;
79 }
80 }
81
82private:
83 virtual void onEmitCode(EmitArgs&, GrGPArgs*) = 0;
84
85 struct TransformUniform {
86 UniformHandle fHandle;
87 GrSLType fType = kVoid_GrSLType;
88 SkMatrix fCurrentValue = SkMatrix::InvalidMatrix();
89 };
90
91 SkTArray<TransformUniform, true> fInstalledTransforms;
92
93 typedef GrGLSLPrimitiveProcessor INHERITED;
94};
95
96#endif
97