/src/skia/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
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1 | | /* |
2 | | * Copyright 2014 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 GrGLSLFragmentShaderBuilder_DEFINED |
9 | | #define GrGLSLFragmentShaderBuilder_DEFINED |
10 | | |
11 | | #include "src/gpu/GrBlend.h" |
12 | | #include "src/gpu/GrFragmentProcessor.h" |
13 | | #include "src/gpu/GrProcessor.h" |
14 | | #include "src/gpu/glsl/GrGLSLShaderBuilder.h" |
15 | | |
16 | | class GrRenderTarget; |
17 | | class GrGLSLVarying; |
18 | | |
19 | | /* |
20 | | * This class is used by fragment processors to build their fragment code. |
21 | | */ |
22 | | class GrGLSLFPFragmentBuilder : virtual public GrGLSLShaderBuilder { |
23 | | public: |
24 | | /** Appease the compiler; the derived class initializes GrGLSLShaderBuilder. */ |
25 | 0 | GrGLSLFPFragmentBuilder() : GrGLSLShaderBuilder(nullptr) { |
26 | | // Suppress unused warning error |
27 | 0 | (void) fPadding; |
28 | 0 | } |
29 | | |
30 | | enum class ScopeFlags { |
31 | | // Every fragment will always execute this code, and will do it exactly once. |
32 | | kTopLevel = 0, |
33 | | // Either all fragments in a given primitive, or none, will execute this code. |
34 | | kInsidePerPrimitiveBranch = (1 << 0), |
35 | | // Any given fragment may or may not execute this code. |
36 | | kInsidePerPixelBranch = (1 << 1), |
37 | | // This code will be executed more than once. |
38 | | kInsideLoop = (1 << 2) |
39 | | }; |
40 | | |
41 | | void writeProcessorFunction(GrFragmentProcessor::ProgramImpl*, |
42 | | GrFragmentProcessor::ProgramImpl::EmitArgs&); |
43 | | |
44 | | virtual void forceHighPrecision() = 0; |
45 | | |
46 | | /** Returns the variable name that holds the color of the destination pixel. This may be nullptr |
47 | | * if no effect advertised that it will read the destination. */ |
48 | | virtual const char* dstColor() = 0; |
49 | | |
50 | | private: |
51 | | /** |
52 | | * These are called before/after calling emitCode on a child proc to update mangling. |
53 | | */ |
54 | | virtual void onBeforeChildProcEmitCode() = 0; |
55 | | virtual void onAfterChildProcEmitCode() = 0; |
56 | | |
57 | | virtual const SkString& getMangleString() const = 0; |
58 | | |
59 | | // WARNING: LIke GrRenderTargetProxy, changes to this can cause issues in ASAN. This is caused |
60 | | // by GrGLSLProgramBuilder's GrTBlockLists requiring 16 byte alignment, but since |
61 | | // GrGLSLFragmentShaderBuilder has a virtual diamond hierarchy, ASAN requires all this pointers |
62 | | // to start aligned, even though clang is already correctly offsetting the individual fields |
63 | | // that require the larger alignment. In the current world, this extra padding is sufficient to |
64 | | // correctly initialize GrGLSLXPFragmentBuilder second. |
65 | | char fPadding[4] = {}; |
66 | | }; |
67 | | |
68 | | GR_MAKE_BITFIELD_CLASS_OPS(GrGLSLFPFragmentBuilder::ScopeFlags) |
69 | | |
70 | | /* |
71 | | * This class is used by Xfer processors to build their fragment code. |
72 | | */ |
73 | | class GrGLSLXPFragmentBuilder : virtual public GrGLSLShaderBuilder { |
74 | | public: |
75 | | /** Appease the compiler; the derived class initializes GrGLSLShaderBuilder. */ |
76 | 0 | GrGLSLXPFragmentBuilder() : GrGLSLShaderBuilder(nullptr) {} |
77 | | |
78 | | virtual bool hasCustomColorOutput() const = 0; |
79 | | virtual bool hasSecondaryOutput() const = 0; |
80 | | |
81 | | /** Returns the variable name that holds the color of the destination pixel. This may be nullptr |
82 | | * if no effect advertised that it will read the destination. */ |
83 | | virtual const char* dstColor() = 0; |
84 | | |
85 | | /** Adds any necessary layout qualifiers in order to legalize the supplied blend equation with |
86 | | this shader. It is only legal to call this method with an advanced blend equation, and only |
87 | | if these equations are supported. */ |
88 | | virtual void enableAdvancedBlendEquationIfNeeded(GrBlendEquation) = 0; |
89 | | }; |
90 | | |
91 | | /* |
92 | | * This class implements the various fragment builder interfaces. |
93 | | */ |
94 | | class GrGLSLFragmentShaderBuilder : public GrGLSLFPFragmentBuilder, public GrGLSLXPFragmentBuilder { |
95 | | public: |
96 | | GrGLSLFragmentShaderBuilder(GrGLSLProgramBuilder* program); |
97 | | |
98 | | // Shared FP/XP interface. |
99 | | const char* dstColor() override; |
100 | | |
101 | | // GrGLSLFPFragmentBuilder interface. |
102 | 0 | void forceHighPrecision() override { fForceHighPrecision = true; } |
103 | | |
104 | | // GrGLSLXPFragmentBuilder interface. |
105 | 0 | bool hasCustomColorOutput() const override { return SkToBool(fCustomColorOutput); } |
106 | 0 | bool hasSecondaryOutput() const override { return fHasSecondaryOutput; } |
107 | | void enableAdvancedBlendEquationIfNeeded(GrBlendEquation) override; |
108 | | |
109 | | private: |
110 | | // GrGLSLFPFragmentBuilder private interface. |
111 | | void onBeforeChildProcEmitCode() override; |
112 | | void onAfterChildProcEmitCode() override; |
113 | 0 | const SkString& getMangleString() const override { return fMangleString; } |
114 | | |
115 | | // Private public interface, used by GrGLProgramBuilder to build a fragment shader |
116 | | void enableCustomOutput(); |
117 | | void enableSecondaryOutput(); |
118 | | const char* getPrimaryColorOutputName() const; |
119 | | const char* getSecondaryColorOutputName() const; |
120 | | bool primaryColorOutputIsInOut() const; |
121 | | |
122 | | #ifdef SK_DEBUG |
123 | | // As GLSLProcessors emit code, there are some conditions we need to verify. We use the below |
124 | | // state to track this. The reset call is called per processor emitted. |
125 | | bool fHasReadDstColorThisStage_DebugOnly = false; |
126 | | |
127 | 0 | void debugOnly_resetPerStageVerification() { |
128 | 0 | fHasReadDstColorThisStage_DebugOnly = false; |
129 | 0 | } |
130 | | #endif |
131 | | |
132 | 0 | static const char* DeclaredColorOutputName() { return "sk_FragColor"; } |
133 | 0 | static const char* DeclaredSecondaryColorOutputName() { return "fsSecondaryColorOut"; } |
134 | | |
135 | | GrSurfaceOrigin getSurfaceOrigin() const; |
136 | | |
137 | | void onFinalize() override; |
138 | | |
139 | | static constexpr const char kDstColorName[] = "_dstColor"; |
140 | | |
141 | | /* |
142 | | * State that tracks which child proc in the proc tree is currently emitting code. This is |
143 | | * used to update the fMangleString, which is used to mangle the names of uniforms and functions |
144 | | * emitted by the proc. fSubstageIndices is a stack: its count indicates how many levels deep |
145 | | * we are in the tree, and its second-to-last value is the index of the child proc at that |
146 | | * level which is currently emitting code. For example, if fSubstageIndices = [3, 1, 2, 0], that |
147 | | * means we're currently emitting code for the base proc's 3rd child's 1st child's 2nd child. |
148 | | */ |
149 | | SkTArray<int> fSubstageIndices; |
150 | | |
151 | | /* |
152 | | * The mangle string is used to mangle the names of uniforms/functions emitted by the child |
153 | | * procs so no duplicate uniforms/functions appear in the generated shader program. The mangle |
154 | | * string is simply based on fSubstageIndices. For example, if fSubstageIndices = [3, 1, 2, 0], |
155 | | * then the manglestring will be "_c3_c1_c2", and any uniform/function emitted by that proc will |
156 | | * have "_c3_c1_c2" appended to its name, which can be interpreted as "base proc's 3rd child's |
157 | | * 1st child's 2nd child". |
158 | | */ |
159 | | SkString fMangleString; |
160 | | |
161 | | GrShaderVar* fCustomColorOutput = nullptr; |
162 | | |
163 | | bool fSetupFragPosition = false; |
164 | | bool fHasSecondaryOutput = false; |
165 | | bool fHasModifiedSampleMask = false; |
166 | | bool fForceHighPrecision = false; |
167 | | |
168 | | friend class GrGLSLProgramBuilder; |
169 | | friend class GrGLProgramBuilder; |
170 | | friend class GrVkPipelineStateBuilder; |
171 | | }; |
172 | | |
173 | | #endif |