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comparison: gfx/skia/trunk/src/gpu/gl/GrGLShaderBuilder.h

gfx/skia/trunk/src/gpu/gl/GrGLShaderBuilder.h

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1 /*
2 * Copyright 2012 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 GrGLShaderBuilder_DEFINED
9 #define GrGLShaderBuilder_DEFINED
10
11 #include "GrAllocator.h"
12 #include "GrBackendEffectFactory.h"
13 #include "GrColor.h"
14 #include "GrEffect.h"
15 #include "SkTypes.h"
16 #include "gl/GrGLProgramEffects.h"
17 #include "gl/GrGLSL.h"
18 #include "gl/GrGLUniformManager.h"
19
20 #include <stdarg.h>
21
22 class GrGLContextInfo;
23 class GrEffectStage;
24 class GrGLProgramDesc;
25
26 /**
27 Contains all the incremental state of a shader as it is being built,as well as helpers to
28 manipulate that state.
29 */
30 class GrGLShaderBuilder {
31 public:
32 typedef GrTAllocator<GrGLShaderVar> VarArray;
33 typedef GrBackendEffectFactory::EffectKey EffectKey;
34 typedef GrGLProgramEffects::TextureSampler TextureSampler;
35 typedef GrGLProgramEffects::TransformedCoordsArray TransformedCoordsArray;
36 typedef GrGLUniformManager::BuilderUniform BuilderUniform;
37
38 enum ShaderVisibility {
39 kVertex_Visibility = 0x1,
40 kGeometry_Visibility = 0x2,
41 kFragment_Visibility = 0x4,
42 };
43
44 GrGLShaderBuilder(GrGpuGL*, GrGLUniformManager&, const GrGLProgramDesc&);
45 virtual ~GrGLShaderBuilder() {}
46
47 /**
48 * Use of these features may require a GLSL extension to be enabled. Shaders may not compile
49 * if code is added that uses one of these features without calling enableFeature()
50 */
51 enum GLSLFeature {
52 kStandardDerivatives_GLSLFeature = 0,
53
54 kLastGLSLFeature = kStandardDerivatives_GLSLFeature
55 };
56
57 /**
58 * If the feature is supported then true is returned and any necessary #extension declarations
59 * are added to the shaders. If the feature is not supported then false will be returned.
60 */
61 bool enableFeature(GLSLFeature);
62
63 /**
64 * Called by GrGLEffects to add code the fragment shader.
65 */
66 void fsCodeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
67 va_list args;
68 va_start(args, format);
69 fFSCode.appendVAList(format, args);
70 va_end(args);
71 }
72
73 void fsCodeAppend(const char* str) { fFSCode.append(str); }
74
75 /** Appends a 2D texture sample with projection if necessary. coordType must either be Vec2f or
76 Vec3f. The latter is interpreted as projective texture coords. The vec length and swizzle
77 order of the result depends on the GrTextureAccess associated with the TextureSampler. */
78 void appendTextureLookup(SkString* out,
79 const TextureSampler&,
80 const char* coordName,
81 GrSLType coordType = kVec2f_GrSLType) const;
82
83 /** Version of above that appends the result to the fragment shader code instead.*/
84 void fsAppendTextureLookup(const TextureSampler&,
85 const char* coordName,
86 GrSLType coordType = kVec2f_GrSLType);
87
88
89 /** Does the work of appendTextureLookup and modulates the result by modulation. The result is
90 always a vec4. modulation and the swizzle specified by TextureSampler must both be vec4 or
91 float. If modulation is "" or NULL it this function acts as though appendTextureLookup were
92 called. */
93 void fsAppendTextureLookupAndModulate(const char* modulation,
94 const TextureSampler&,
95 const char* coordName,
96 GrSLType coordType = kVec2f_GrSLType);
97
98 /** Emits a helper function outside of main() in the fragment shader. */
99 void fsEmitFunction(GrSLType returnType,
100 const char* name,
101 int argCnt,
102 const GrGLShaderVar* args,
103 const char* body,
104 SkString* outName);
105
106 typedef uint8_t DstReadKey;
107 typedef uint8_t FragPosKey;
108
109 /** Returns a key for adding code to read the copy-of-dst color in service of effects that
110 require reading the dst. It must not return 0 because 0 indicates that there is no dst
111 copy read at all (in which case this function should not be called). */
112 static DstReadKey KeyForDstRead(const GrTexture* dstCopy, const GrGLCaps&);
113
114 /** Returns a key for reading the fragment location. This should only be called if there is an
115 effect that will requires the fragment position. If the fragment position is not required,
116 the key is 0. */
117 static FragPosKey KeyForFragmentPosition(const GrRenderTarget* dst, const GrGLCaps&);
118
119 /** If texture swizzling is available using tex parameters then it is preferred over mangling
120 the generated shader code. This potentially allows greater reuse of cached shaders. */
121 static const GrGLenum* GetTexParamSwizzle(GrPixelConfig config, const GrGLCaps& caps);
122
123 /** Add a uniform variable to the current program, that has visibility in one or more shaders.
124 visibility is a bitfield of ShaderVisibility values indicating from which shaders the
125 uniform should be accessible. At least one bit must be set. Geometry shader uniforms are not
126 supported at this time. The actual uniform name will be mangled. If outName is not NULL then
127 it will refer to the final uniform name after return. Use the addUniformArray variant to add
128 an array of uniforms.
129 */
130 GrGLUniformManager::UniformHandle addUniform(uint32_t visibility,
131 GrSLType type,
132 const char* name,
133 const char** outName = NULL) {
134 return this->addUniformArray(visibility, type, name, GrGLShaderVar::kNonArray, outName);
135 }
136 GrGLUniformManager::UniformHandle addUniformArray(uint32_t visibility,
137 GrSLType type,
138 const char* name,
139 int arrayCount,
140 const char** outName = NULL);
141
142 const GrGLShaderVar& getUniformVariable(GrGLUniformManager::UniformHandle u) const {
143 return fUniformManager.getBuilderUniform(fUniforms, u).fVariable;
144 }
145
146 /**
147 * Shortcut for getUniformVariable(u).c_str()
148 */
149 const char* getUniformCStr(GrGLUniformManager::UniformHandle u) const {
150 return this->getUniformVariable(u).c_str();
151 }
152
153 /**
154 * This returns a variable name to access the 2D, perspective correct version of the coords in
155 * the fragment shader. If the coordinates at index are 3-dimensional, it immediately emits a
156 * perspective divide into the fragment shader (xy / z) to convert them to 2D.
157 */
158 SkString ensureFSCoords2D(const TransformedCoordsArray&, int index);
159
160 /** Returns a variable name that represents the position of the fragment in the FS. The position
161 is in device space (e.g. 0,0 is the top left and pixel centers are at half-integers). */
162 const char* fragmentPosition();
163
164 /** Returns the color of the destination pixel. This may be NULL if no effect advertised
165 that it will read the destination. */
166 const char* dstColor();
167
168 /**
169 * Interfaces used by GrGLProgram.
170 */
171 const GrGLSLExpr4& getInputColor() const {
172 return fInputColor;
173 }
174 const GrGLSLExpr4& getInputCoverage() const {
175 return fInputCoverage;
176 }
177
178 /**
179 * Adds code for effects and returns a GrGLProgramEffects* object. The caller is responsible for
180 * deleting it when finished. effectStages contains the effects to add. effectKeys[i] is the key
181 * generated from effectStages[i]. inOutFSColor specifies the input color to the first stage and
182 * is updated to be the output color of the last stage.
183 * The handles to texture samplers for effectStage[i] are added to
184 * effectSamplerHandles[i].
185 */
186 virtual GrGLProgramEffects* createAndEmitEffects(const GrEffectStage* effectStages[],
187 const EffectKey effectKeys[],
188 int effectCnt,
189 GrGLSLExpr4* inOutFSColor) = 0;
190
191 const char* getColorOutputName() const;
192 const char* enableSecondaryOutput();
193
194 GrGLUniformManager::UniformHandle getRTHeightUniform() const { return fRTHeightUniform; }
195 GrGLUniformManager::UniformHandle getDstCopyTopLeftUniform() const {
196 return fDstCopyTopLeftUniform;
197 }
198 GrGLUniformManager::UniformHandle getDstCopyScaleUniform() const {
199 return fDstCopyScaleUniform;
200 }
201 GrGLUniformManager::UniformHandle getColorUniform() const { return fColorUniform; }
202 GrGLUniformManager::UniformHandle getCoverageUniform() const { return fCoverageUniform; }
203 GrGLUniformManager::UniformHandle getDstCopySamplerUniform() const {
204 return fDstCopySamplerUniform;
205 }
206
207 bool finish(GrGLuint* outProgramId);
208
209 const GrGLContextInfo& ctxInfo() const;
210
211 /**
212 * Helper for begining and ending a block in the fragment code. TODO: Make GrGLShaderBuilder
213 * aware of all blocks and turn single \t's into the correct number of tabs (or spaces) so that
214 * our shaders print pretty without effect writers tracking indentation.
215 */
216 class FSBlock {
217 public:
218 FSBlock(GrGLShaderBuilder* builder) : fBuilder(builder) {
219 SkASSERT(NULL != builder);
220 fBuilder->fsCodeAppend("\t{\n");
221 }
222
223 ~FSBlock() {
224 fBuilder->fsCodeAppend("\t}\n");
225 }
226 private:
227 GrGLShaderBuilder* fBuilder;
228 };
229
230 protected:
231 GrGpuGL* gpu() const { return fGpu; }
232
233 void setInputColor(const GrGLSLExpr4& inputColor) { fInputColor = inputColor; }
234 void setInputCoverage(const GrGLSLExpr4& inputCoverage) { fInputCoverage = inputCoverage; }
235
236 /** Add input/output variable declarations (i.e. 'varying') to the fragment shader. */
237 GrGLShaderVar& fsInputAppend() { return fFSInputs.push_back(); }
238
239 // Generates a name for a variable. The generated string will be name prefixed by the prefix
240 // char (unless the prefix is '\0'). It also mangles the name to be stage-specific if we're
241 // generating stage code.
242 void nameVariable(SkString* out, char prefix, const char* name);
243
244 // Helper for emitEffects().
245 void createAndEmitEffects(GrGLProgramEffectsBuilder*,
246 const GrEffectStage* effectStages[],
247 const EffectKey effectKeys[],
248 int effectCnt,
249 GrGLSLExpr4* inOutFSColor);
250
251 virtual bool compileAndAttachShaders(GrGLuint programId, SkTDArray<GrGLuint>* shaderIds) const;
252 virtual void bindProgramLocations(GrGLuint programId) const;
253
254 void appendDecls(const VarArray&, SkString*) const;
255 void appendUniformDecls(ShaderVisibility, SkString*) const;
256
257 private:
258 class CodeStage : public SkNoncopyable {
259 public:
260 CodeStage() : fNextIndex(0), fCurrentIndex(-1), fEffectStage(NULL) {}
261
262 bool inStageCode() const {
263 this->validate();
264 return NULL != fEffectStage;
265 }
266
267 const GrEffectStage* effectStage() const {
268 this->validate();
269 return fEffectStage;
270 }
271
272 int stageIndex() const {
273 this->validate();
274 return fCurrentIndex;
275 }
276
277 class AutoStageRestore : public SkNoncopyable {
278 public:
279 AutoStageRestore(CodeStage* codeStage, const GrEffectStage* newStage) {
280 SkASSERT(NULL != codeStage);
281 fSavedIndex = codeStage->fCurrentIndex;
282 fSavedEffectStage = codeStage->fEffectStage;
283
284 if (NULL == newStage) {
285 codeStage->fCurrentIndex = -1;
286 } else {
287 codeStage->fCurrentIndex = codeStage->fNextIndex++;
288 }
289 codeStage->fEffectStage = newStage;
290
291 fCodeStage = codeStage;
292 }
293 ~AutoStageRestore() {
294 fCodeStage->fCurrentIndex = fSavedIndex;
295 fCodeStage->fEffectStage = fSavedEffectStage;
296 }
297 private:
298 CodeStage* fCodeStage;
299 int fSavedIndex;
300 const GrEffectStage* fSavedEffectStage;
301 };
302 private:
303 void validate() const { SkASSERT((NULL == fEffectStage) == (-1 == fCurrentIndex)); }
304 int fNextIndex;
305 int fCurrentIndex;
306 const GrEffectStage* fEffectStage;
307 } fCodeStage;
308
309 /**
310 * Features that should only be enabled by GrGLShaderBuilder itself.
311 */
312 enum GLSLPrivateFeature {
313 kFragCoordConventions_GLSLPrivateFeature = kLastGLSLFeature + 1,
314 kEXTShaderFramebufferFetch_GLSLPrivateFeature,
315 kNVShaderFramebufferFetch_GLSLPrivateFeature,
316 };
317 bool enablePrivateFeature(GLSLPrivateFeature);
318
319 // If we ever have VS/GS features we can expand this to take a bitmask of ShaderVisibility and
320 // track the enables separately for each shader.
321 void addFSFeature(uint32_t featureBit, const char* extensionName);
322
323 // Interpretation of DstReadKey when generating code
324 enum {
325 kNoDstRead_DstReadKey = 0,
326 kYesDstRead_DstReadKeyBit = 0x1, // Set if we do a dst-copy-read.
327 kUseAlphaConfig_DstReadKeyBit = 0x2, // Set if dst-copy config is alpha only.
328 kTopLeftOrigin_DstReadKeyBit = 0x4, // Set if dst-copy origin is top-left.
329 };
330
331 enum {
332 kNoFragPosRead_FragPosKey = 0, // The fragment positition will not be needed.
333 kTopLeftFragPosRead_FragPosKey = 0x1,// Read frag pos relative to top-left.
334 kBottomLeftFragPosRead_FragPosKey = 0x2,// Read frag pos relative to bottom-left.
335 };
336
337 GrGpuGL* fGpu;
338 GrGLUniformManager& fUniformManager;
339 uint32_t fFSFeaturesAddedMask;
340 SkString fFSFunctions;
341 SkString fFSExtensions;
342 VarArray fFSInputs;
343 VarArray fFSOutputs;
344 GrGLUniformManager::BuilderUniformArray fUniforms;
345
346 SkString fFSCode;
347
348 bool fSetupFragPosition;
349 GrGLUniformManager::UniformHandle fDstCopySamplerUniform;
350
351 GrGLSLExpr4 fInputColor;
352 GrGLSLExpr4 fInputCoverage;
353
354 bool fHasCustomColorOutput;
355 bool fHasSecondaryOutput;
356
357 GrGLUniformManager::UniformHandle fRTHeightUniform;
358 GrGLUniformManager::UniformHandle fDstCopyTopLeftUniform;
359 GrGLUniformManager::UniformHandle fDstCopyScaleUniform;
360 GrGLUniformManager::UniformHandle fColorUniform;
361 GrGLUniformManager::UniformHandle fCoverageUniform;
362
363 bool fTopLeftFragPosRead;
364 };
365
366 ////////////////////////////////////////////////////////////////////////////////
367
368 class GrGLFullShaderBuilder : public GrGLShaderBuilder {
369 public:
370 GrGLFullShaderBuilder(GrGpuGL*, GrGLUniformManager&, const GrGLProgramDesc&);
371
372 /**
373 * Called by GrGLEffects to add code to one of the shaders.
374 */
375 void vsCodeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
376 va_list args;
377 va_start(args, format);
378 fVSCode.appendVAList(format, args);
379 va_end(args);
380 }
381
382 void vsCodeAppend(const char* str) { fVSCode.append(str); }
383
384 /** Add a vertex attribute to the current program that is passed in from the vertex data.
385 Returns false if the attribute was already there, true otherwise. */
386 bool addAttribute(GrSLType type, const char* name);
387
388 /** Add a varying variable to the current program to pass values between vertex and fragment
389 shaders. If the last two parameters are non-NULL, they are filled in with the name
390 generated. */
391 void addVarying(GrSLType type,
392 const char* name,
393 const char** vsOutName = NULL,
394 const char** fsInName = NULL);
395
396 /** Returns a vertex attribute that represents the vertex position in the VS. This is the
397 pre-matrix position and is commonly used by effects to compute texture coords via a matrix.
398 */
399 const GrGLShaderVar& positionAttribute() const { return *fPositionVar; }
400
401 /** Returns a vertex attribute that represents the local coords in the VS. This may be the same
402 as positionAttribute() or it may not be. It depends upon whether the rendering code
403 specified explicit local coords or not in the GrDrawState. */
404 const GrGLShaderVar& localCoordsAttribute() const { return *fLocalCoordsVar; }
405
406 /**
407 * Are explicit local coordinates provided as input to the vertex shader.
408 */
409 bool hasExplicitLocalCoords() const { return (fLocalCoordsVar != fPositionVar); }
410
411 bool addEffectAttribute(int attributeIndex, GrSLType type, const SkString& name);
412 const SkString* getEffectAttributeName(int attributeIndex) const;
413
414 virtual GrGLProgramEffects* createAndEmitEffects(
415 const GrEffectStage* effectStages[],
416 const EffectKey effectKeys[],
417 int effectCnt,
418 GrGLSLExpr4* inOutFSColor) SK_OVERRIDE;
419
420 GrGLUniformManager::UniformHandle getViewMatrixUniform() const {
421 return fViewMatrixUniform;
422 }
423
424 protected:
425 virtual bool compileAndAttachShaders(GrGLuint programId, SkTDArray<GrGLuint>* shaderIds) const SK_OVERRIDE;
426 virtual void bindProgramLocations(GrGLuint programId) const SK_OVERRIDE;
427
428 private:
429 const GrGLProgramDesc& fDesc;
430 VarArray fVSAttrs;
431 VarArray fVSOutputs;
432 VarArray fGSInputs;
433 VarArray fGSOutputs;
434
435 SkString fVSCode;
436
437 struct AttributePair {
438 void set(int index, const SkString& name) {
439 fIndex = index; fName = name;
440 }
441 int fIndex;
442 SkString fName;
443 };
444 SkSTArray<10, AttributePair, true> fEffectAttributes;
445
446 GrGLUniformManager::UniformHandle fViewMatrixUniform;
447
448 GrGLShaderVar* fPositionVar;
449 GrGLShaderVar* fLocalCoordsVar;
450
451 typedef GrGLShaderBuilder INHERITED;
452 };
453
454 ////////////////////////////////////////////////////////////////////////////////
455
456 class GrGLFragmentOnlyShaderBuilder : public GrGLShaderBuilder {
457 public:
458 GrGLFragmentOnlyShaderBuilder(GrGpuGL*, GrGLUniformManager&, const GrGLProgramDesc&);
459
460 int getNumTexCoordSets() const { return fNumTexCoordSets; }
461 int addTexCoordSets(int count);
462
463 virtual GrGLProgramEffects* createAndEmitEffects(
464 const GrEffectStage* effectStages[],
465 const EffectKey effectKeys[],
466 int effectCnt,
467 GrGLSLExpr4* inOutFSColor) SK_OVERRIDE;
468
469 private:
470 int fNumTexCoordSets;
471
472 typedef GrGLShaderBuilder INHERITED;
473 };
474
475 #endif

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