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 GrGLSLFragmentProcessor_DEFINED
9 #define GrGLSLFragmentProcessor_DEFINED
10 
11 #include "glsl/GrGLSLProcessorTypes.h"
12 #include "glsl/GrGLSLProgramDataManager.h"
13 #include "glsl/GrGLSLTextureSampler.h"
14 
15 class GrProcessor;
16 class GrProcessorKeyBuilder;
17 class GrGLSLCaps;
18 class GrGLSLFPBuilder;
19 class GrGLSLFPFragmentBuilder;
20 class GrGLSLUniformHandler;
21 
22 class GrGLSLFragmentProcessor {
23 public:
GrGLSLFragmentProcessor()24     GrGLSLFragmentProcessor() {}
25 
~GrGLSLFragmentProcessor()26     virtual ~GrGLSLFragmentProcessor() {
27         for (int i = 0; i < fChildProcessors.count(); ++i) {
28             delete fChildProcessors[i];
29         }
30     }
31 
32     typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;
33     typedef GrGLSLTextureSampler::TextureSamplerArray TextureSamplerArray;
34 
35     /** Called when the program stage should insert its code into the shaders. The code in each
36         shader will be in its own block ({}) and so locally scoped names will not collide across
37         stages.
38 
39         @param builder      Interface used to emit code in the shaders.
40         @param processor    The processor that generated this program stage.
41         @param key          The key that was computed by GenKey() from the generating GrProcessor.
42         @param outputColor  A predefined vec4 in the FS in which the stage should place its output
43                             color (or coverage).
44         @param inputColor   A vec4 that holds the input color to the stage in the FS. This may be
45                             nullptr in which case the implied input is solid white (all ones).
46                             TODO: Better system for communicating optimization info (e.g. input
47                             color is solid white, trans black, known to be opaque, etc.) that allows
48                             the processor to communicate back similar known info about its output.
49         @param samplers     Contains one entry for each GrTextureAccess of the GrProcessor. These
50                             can be passed to the builder to emit texture reads in the generated
51                             code.
52      */
53 
54     struct EmitArgs {
EmitArgsEmitArgs55         EmitArgs(GrGLSLFPFragmentBuilder* fragBuilder,
56                  GrGLSLUniformHandler* uniformHandler,
57                  const GrGLSLCaps* caps,
58                  const GrFragmentProcessor& fp,
59                  const char* outputColor,
60                  const char* inputColor,
61                  const GrGLSLTransformedCoordsArray& coords,
62                  const TextureSamplerArray& samplers)
63             : fFragBuilder(fragBuilder)
64             , fUniformHandler(uniformHandler)
65             , fGLSLCaps(caps)
66             , fFp(fp)
67             , fOutputColor(outputColor)
68             , fInputColor(inputColor)
69             , fCoords(coords)
70             , fSamplers(samplers) {}
71         GrGLSLFPFragmentBuilder* fFragBuilder;
72         GrGLSLUniformHandler* fUniformHandler;
73         const GrGLSLCaps* fGLSLCaps;
74         const GrFragmentProcessor& fFp;
75         const char* fOutputColor;
76         const char* fInputColor;
77         const GrGLSLTransformedCoordsArray& fCoords;
78         const TextureSamplerArray& fSamplers;
79     };
80 
81     virtual void emitCode(EmitArgs&) = 0;
82 
83     void setData(const GrGLSLProgramDataManager& pdman, const GrFragmentProcessor& processor);
84 
GenKey(const GrProcessor &,const GrGLSLCaps &,GrProcessorKeyBuilder *)85     static void GenKey(const GrProcessor&, const GrGLSLCaps&, GrProcessorKeyBuilder*) {}
86 
numChildProcessors()87     int numChildProcessors() const { return fChildProcessors.count(); }
88 
childProcessor(int index)89     GrGLSLFragmentProcessor* childProcessor(int index) const {
90         return fChildProcessors[index];
91     }
92 
93     /** Will emit the code of a child proc in its own scope. Pass in the parent's EmitArgs and
94      *  emitChild will automatically extract the coords and samplers of that child and pass them
95      *  on to the child's emitCode(). Also, any uniforms or functions emitted by the child will
96      *  have their names mangled to prevent redefinitions. The output color name is also mangled
97      *  therefore in an in/out param. It will be declared in mangled form by emitChild(). It is
98      *  legal to pass nullptr as inputColor, since all fragment processors are required to work
99      *  without an input color.
100      */
101     void emitChild(int childIndex, const char* inputColor, SkString* outputColor,
102                    EmitArgs& parentArgs);
103 
104     /** Variation that uses the parent's output color variable to hold the child's output.*/
105     void emitChild(int childIndex, const char* inputColor, EmitArgs& parentArgs);
106 
107 protected:
108     /** A GrGLSLFragmentProcessor instance can be reused with any GrFragmentProcessor that produces
109     the same stage key; this function reads data from a GrFragmentProcessor and uploads any
110     uniform variables required by the shaders created in emitCode(). The GrFragmentProcessor
111     parameter is guaranteed to be of the same type that created this GrGLSLFragmentProcessor and
112     to have an identical processor key as the one that created this GrGLSLFragmentProcessor.  */
113     // TODO update this to pass in GrFragmentProcessor
onSetData(const GrGLSLProgramDataManager &,const GrProcessor &)114     virtual void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) {}
115 
116 private:
117     void internalEmitChild(int, const char*, const char*, EmitArgs&);
118 
119     SkTArray<GrGLSLFragmentProcessor*, true> fChildProcessors;
120 
121     friend class GrFragmentProcessor;
122 };
123 
124 #endif
125