src/gpu/gl/GrGLShaderBuilder.cpp - platform/external/skia - Gitiles

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "gl/GrGLShaderBuilder.h"
 #include "gl/GrGLProgram.h"
 #include "gl/GrGLUniformHandle.h"
 #include "GrTexture.h"

 // number of each input/output type in a single allocation block
 static const int kVarsPerBlock = 8;

 // except FS outputs where we expect 2 at most.
 static const int kMaxFSOutputs = 2;

 // ES2 FS only guarantees mediump and lowp support
 static const GrGLShaderVar::Precision kDefaultFragmentPrecision = GrGLShaderVar::kMedium_Precision;

 typedef GrGLUniformManager::UniformHandle UniformHandle;
 ///////////////////////////////////////////////////////////////////////////////

 namespace {

 inline const char* sample_function_name(GrSLType type, GrGLSLGeneration glslGen) {
     if (kVec2f_GrSLType == type) {
         return glslGen >= k130_GrGLSLGeneration ? "texture" : "texture2D";
     } else {
         GrAssert(kVec3f_GrSLType == type);
         return glslGen >= k130_GrGLSLGeneration ? "textureProj" : "texture2DProj";
     }
 }

 /**
  * Do we need to either map r,g,b->a or a->r.
  */
 inline bool swizzle_requires_alpha_remapping(const GrGLCaps& caps,
                                              const GrTextureAccess& access) {
     if (GrPixelConfigIsAlphaOnly(access.getTexture()->config())) {
         if (caps.textureRedSupport() && (GrTextureAccess::kA_SwizzleFlag & access.swizzleMask())) {
             return true;
         }
         if (GrTextureAccess::kRGB_SwizzleMask & access.swizzleMask()) {
             return true;
         }
     }
     return false;
 }

 void append_swizzle(SkString* outAppend,
                     const GrTextureAccess& access,
                     const GrGLCaps& caps) {
     const char* swizzle = access.getSwizzle();
     char mangledSwizzle[5];

     // The swizzling occurs using texture params instead of shader-mangling if ARB_texture_swizzle
     // is available.
     if (!caps.textureSwizzleSupport() && GrPixelConfigIsAlphaOnly(access.getTexture()->config())) {
         char alphaChar = caps.textureRedSupport() ? 'r' : 'a';
         int i;
         for (i = 0; '\0' != swizzle[i]; ++i) {
             mangledSwizzle[i] = alphaChar;
         }
         mangledSwizzle[i] ='\0';
         swizzle = mangledSwizzle;
     }
     // For shader prettiness we omit the swizzle rather than appending ".rgba".
     if (memcmp(swizzle, "rgba", 4)) {
         outAppend->appendf(".%s", swizzle);
     }
 }

 }

 ///////////////////////////////////////////////////////////////////////////////

 // Architectural assumption: always 2-d input coords.
 // Likely to become non-constant and non-static, perhaps even
 // varying by stage, if we use 1D textures for gradients!
 //const int GrGLShaderBuilder::fCoordDims = 2;

 GrGLShaderBuilder::GrGLShaderBuilder(const GrGLContextInfo& ctxInfo,
                                      GrGLUniformManager& uniformManager)
     : fUniforms(kVarsPerBlock)
     , fVSAttrs(kVarsPerBlock)
     , fVSOutputs(kVarsPerBlock)
     , fGSInputs(kVarsPerBlock)
     , fGSOutputs(kVarsPerBlock)
     , fFSInputs(kVarsPerBlock)
     , fFSOutputs(kMaxFSOutputs)
     , fUsesGS(false)
     , fCtxInfo(ctxInfo)
     , fUniformManager(uniformManager)
     , fCurrentStageIdx(kNonStageIdx)
     , fSetupFragPosition(false)
     , fRTHeightUniform(GrGLUniformManager::kInvalidUniformHandle) {

     fPositionVar = &fVSAttrs.push_back();
     fPositionVar->set(kVec2f_GrSLType, GrGLShaderVar::kAttribute_TypeModifier, "aPosition");
 }

 void GrGLShaderBuilder::codeAppendf(ShaderType type, const char format[], va_list args) {
     SkString* string;
     switch (type) {
         case kVertex_ShaderType:
             string = &fVSCode;
             break;
         case kGeometry_ShaderType:
             string = &fGSCode;
             break;
         case kFragment_ShaderType:
             string = &fFSCode;
             break;
         default:
             GrCrash("Invalid shader type");
     }
     string->appendf(format, args);
 }

 void GrGLShaderBuilder::codeAppend(ShaderType type, const char* str) {
     SkString* string;
     switch (type) {
         case kVertex_ShaderType:
             string = &fVSCode;
             break;
         case kGeometry_ShaderType:
             string = &fGSCode;
             break;
         case kFragment_ShaderType:
             string = &fFSCode;
             break;
         default:
             GrCrash("Invalid shader type");
     }
     string->append(str);
 }

 void GrGLShaderBuilder::appendTextureLookup(SkString* out,
                                             const GrGLShaderBuilder::TextureSampler& sampler,
                                             const char* coordName,
                                             GrSLType varyingType) const {
     GrAssert(NULL != sampler.textureAccess());
     GrAssert(NULL != coordName);

     out->appendf("%s(%s, %s)",
                  sample_function_name(varyingType, fCtxInfo.glslGeneration()),
                  this->getUniformCStr(sampler.fSamplerUniform),
                  coordName);
     append_swizzle(out, *sampler.textureAccess(), fCtxInfo.caps());
 }

 void GrGLShaderBuilder::appendTextureLookup(ShaderType type,
                                             const GrGLShaderBuilder::TextureSampler& sampler,
                                             const char* coordName,
                                             GrSLType varyingType) {
     GrAssert(kFragment_ShaderType == type);
     this->appendTextureLookup(&fFSCode, sampler, coordName, varyingType);
 }

 void GrGLShaderBuilder::appendTextureLookupAndModulate(
                                             ShaderType type,
                                             const char* modulation,
                                             const GrGLShaderBuilder::TextureSampler& sampler,
                                             const char* coordName,
                                             GrSLType varyingType) {
     GrAssert(kFragment_ShaderType == type);
     SkString lookup;
     this->appendTextureLookup(&lookup, sampler, coordName, varyingType);
     GrGLSLModulate4f(&fFSCode, modulation, lookup.c_str());
 }

 GrBackendEffectFactory::EffectKey GrGLShaderBuilder::KeyForTextureAccess(
                                                             const GrTextureAccess& access,
                                                             const GrGLCaps& caps) {
     GrBackendEffectFactory::EffectKey key = 0;

     // Assume that swizzle support implies that we never have to modify a shader to adjust
     // for texture format/swizzle settings.
     if (!caps.textureSwizzleSupport() && swizzle_requires_alpha_remapping(caps, access)) {
         key = 1;
     }
 #if GR_DEBUG
     // Assert that key is set iff the swizzle will be modified.
     SkString origString(access.getSwizzle());
     origString.prepend(".");
     SkString modifiedString;
     append_swizzle(&modifiedString, access, caps);
     if (!modifiedString.size()) {
         modifiedString = ".rgba";
     }
     GrAssert(SkToBool(key) == (modifiedString != origString));
 #endif
     return key;
 }

 const GrGLenum* GrGLShaderBuilder::GetTexParamSwizzle(GrPixelConfig config, const GrGLCaps& caps) {
     if (caps.textureSwizzleSupport() && GrPixelConfigIsAlphaOnly(config)) {
         if (caps.textureRedSupport()) {
             static const GrGLenum gRedSmear[] = { GR_GL_RED, GR_GL_RED, GR_GL_RED, GR_GL_RED };
             return gRedSmear;
         } else {
             static const GrGLenum gAlphaSmear[] = { GR_GL_ALPHA, GR_GL_ALPHA,
                                                     GR_GL_ALPHA, GR_GL_ALPHA };
             return gAlphaSmear;
         }
     } else {
         static const GrGLenum gStraight[] = { GR_GL_RED, GR_GL_GREEN, GR_GL_BLUE, GR_GL_ALPHA };
         return gStraight;
     }
 }

 GrGLUniformManager::UniformHandle GrGLShaderBuilder::addUniformArray(uint32_t visibility,
                                                                      GrSLType type,
                                                                      const char* name,
                                                                      int count,
                                                                      const char** outName) {
     GrAssert(name && strlen(name));
     SkDEBUGCODE(static const uint32_t kVisibilityMask = kVertex_ShaderType | kFragment_ShaderType);
     GrAssert(0 == (~kVisibilityMask & visibility));
     GrAssert(0 != visibility);

     BuilderUniform& uni = fUniforms.push_back();
     UniformHandle h = index_to_handle(fUniforms.count() - 1);
     GR_DEBUGCODE(UniformHandle h2 =)
     fUniformManager.appendUniform(type, count);
     // We expect the uniform manager to initially have no uniforms and that all uniforms are added
     // by this function. Therefore, the handles should match.
     GrAssert(h2 == h);
     uni.fVariable.setType(type);
     uni.fVariable.setTypeModifier(GrGLShaderVar::kUniform_TypeModifier);
     SkString* uniName = uni.fVariable.accessName();
     if (kNonStageIdx == fCurrentStageIdx) {
         uniName->printf("u%s", name);
     } else {
         uniName->printf("u%s%d", name, fCurrentStageIdx);
     }
     uni.fVariable.setArrayCount(count);
     uni.fVisibility = visibility;

     // If it is visible in both the VS and FS, the precision must match.
     // We declare a default FS precision, but not a default VS. So set the var
     // to use the default FS precision.
     if ((kVertex_ShaderType | kFragment_ShaderType) == visibility) {
         // the fragment and vertex precisions must match
         uni.fVariable.setPrecision(kDefaultFragmentPrecision);
     }

     if (NULL != outName) {
         *outName = uni.fVariable.c_str();
     }

     return h;
 }

 const GrGLShaderVar& GrGLShaderBuilder::getUniformVariable(UniformHandle u) const {
     return fUniforms[handle_to_index(u)].fVariable;
 }

 void GrGLShaderBuilder::addVarying(GrSLType type,
                                    const char* name,
                                    const char** vsOutName,
                                    const char** fsInName) {
     fVSOutputs.push_back();
     fVSOutputs.back().setType(type);
     fVSOutputs.back().setTypeModifier(GrGLShaderVar::kOut_TypeModifier);
     if (kNonStageIdx == fCurrentStageIdx) {
         fVSOutputs.back().accessName()->printf("v%s", name);
     } else {
         fVSOutputs.back().accessName()->printf("v%s%d", name, fCurrentStageIdx);
     }
     if (vsOutName) {
         *vsOutName = fVSOutputs.back().getName().c_str();
     }
     // input to FS comes either from VS or GS
     const SkString* fsName;
     if (fUsesGS) {
         // if we have a GS take each varying in as an array
         // and output as non-array.
         fGSInputs.push_back();
         fGSInputs.back().setType(type);
         fGSInputs.back().setTypeModifier(GrGLShaderVar::kIn_TypeModifier);
         fGSInputs.back().setUnsizedArray();
         *fGSInputs.back().accessName() = fVSOutputs.back().getName();
         fGSOutputs.push_back();
         fGSOutputs.back().setType(type);
         fGSOutputs.back().setTypeModifier(GrGLShaderVar::kOut_TypeModifier);
         if (kNonStageIdx == fCurrentStageIdx) {
             fGSOutputs.back().accessName()->printf("g%s", name);
         } else {
             fGSOutputs.back().accessName()->printf("g%s%d", name, fCurrentStageIdx);
         }
         fsName = fGSOutputs.back().accessName();
     } else {
         fsName = fVSOutputs.back().accessName();
     }
     fFSInputs.push_back();
     fFSInputs.back().setType(type);
     fFSInputs.back().setTypeModifier(GrGLShaderVar::kIn_TypeModifier);
     fFSInputs.back().setName(*fsName);
     if (fsInName) {
         *fsInName = fsName->c_str();
     }
 }

 const char* GrGLShaderBuilder::fragmentPosition() {
 #if 1
     if (fCtxInfo.caps().fragCoordConventionsSupport()) {
         if (!fSetupFragPosition) {
             fFSHeader.append("#extension GL_ARB_fragment_coord_conventions: require\n");
             fFSInputs.push_back().set(kVec4f_GrSLType,
                                       GrGLShaderVar::kIn_TypeModifier,
                                       "gl_FragCoord",
                                       GrGLShaderVar::kDefault_Precision,
                                       GrGLShaderVar::kUpperLeft_Origin);
             fSetupFragPosition = true;
         }
         return "gl_FragCoord";
     } else {
         static const char* kCoordName = "fragCoordYDown";
         if (!fSetupFragPosition) {
             GrAssert(GrGLUniformManager::kInvalidUniformHandle == fRTHeightUniform);
             const char* rtHeightName;

             // temporarily change the stage index because we're inserting a uniform whose name
             // shouldn't be mangled to be stage-specific.
             int oldStageIdx = fCurrentStageIdx;
             fCurrentStageIdx = kNonStageIdx;
             fRTHeightUniform = this->addUniform(kFragment_ShaderType,
                                                 kFloat_GrSLType,
                                                 "RTHeight",
                                                 &rtHeightName);
             fCurrentStageIdx = oldStageIdx;

             this->fFSCode.prependf("\tvec4 %s = vec4(gl_FragCoord.x, %s - gl_FragCoord.y, gl_FragCoord.zw);\n",
                                    kCoordName, rtHeightName);
             fSetupFragPosition = true;
         }
         GrAssert(GrGLUniformManager::kInvalidUniformHandle != fRTHeightUniform);
         return kCoordName;
     }
 #else
     // This is the path we'll need to use once we have support for TopLeft
     // render targets.
     if (!fSetupFragPosition) {
         fFSInputs.push_back().set(kVec4f_GrSLType,
                                   GrGLShaderVar::kIn_TypeModifier,
                                   "gl_FragCoord",
                                   GrGLShaderVar::kDefault_Precision);
         fSetupFragPosition = true;
     }
     return "gl_FragCoord";
 #endif
 }


 void GrGLShaderBuilder::emitFunction(ShaderType shader,
                                      GrSLType returnType,
                                      const char* name,
                                      int argCnt,
                                      const GrGLShaderVar* args,
                                      const char* body,
                                      SkString* outName) {
     GrAssert(kFragment_ShaderType == shader);
     fFSFunctions.append(GrGLShaderVar::TypeString(returnType));
     if (kNonStageIdx != fCurrentStageIdx) {
         outName->printf(" %s_%d", name, fCurrentStageIdx);
     } else {
         *outName = name;
     }
     fFSFunctions.append(*outName);
     fFSFunctions.append("(");
     for (int i = 0; i < argCnt; ++i) {
         args[i].appendDecl(fCtxInfo, &fFSFunctions);
         if (i < argCnt - 1) {
             fFSFunctions.append(", ");
         }
     }
     fFSFunctions.append(") {\n");
     fFSFunctions.append(body);
     fFSFunctions.append("}\n\n");
 }

 namespace {

 inline void append_default_precision_qualifier(GrGLShaderVar::Precision p,
                                                GrGLBinding binding,
                                                SkString* str) {
     // Desktop GLSL has added precision qualifiers but they don't do anything.
     if (kES2_GrGLBinding == binding) {
         switch (p) {
             case GrGLShaderVar::kHigh_Precision:
                 str->append("precision highp float;\n");
                 break;
             case GrGLShaderVar::kMedium_Precision:
                 str->append("precision mediump float;\n");
                 break;
             case GrGLShaderVar::kLow_Precision:
                 str->append("precision lowp float;\n");
                 break;
             case GrGLShaderVar::kDefault_Precision:
                 GrCrash("Default precision now allowed.");
             default:
                 GrCrash("Unknown precision value.");
         }
     }
 }
 }

 void GrGLShaderBuilder::appendDecls(const VarArray& vars, SkString* out) const {
     for (int i = 0; i < vars.count(); ++i) {
         vars[i].appendDecl(fCtxInfo, out);
         out->append(";\n");
     }
 }

 void GrGLShaderBuilder::appendUniformDecls(ShaderType stype, SkString* out) const {
     for (int i = 0; i < fUniforms.count(); ++i) {
         if (fUniforms[i].fVisibility & stype) {
             fUniforms[i].fVariable.appendDecl(fCtxInfo, out);
             out->append(";\n");
         }
     }
 }

 void GrGLShaderBuilder::getShader(ShaderType type, SkString* shaderStr) const {
     switch (type) {
         case kVertex_ShaderType:
             *shaderStr = fHeader;
             this->appendUniformDecls(kVertex_ShaderType, shaderStr);
             this->appendDecls(fVSAttrs, shaderStr);
             this->appendDecls(fVSOutputs, shaderStr);
             shaderStr->append("void main() {\n");
             shaderStr->append(fVSCode);
             shaderStr->append("}\n");
             break;
         case kGeometry_ShaderType:
             if (fUsesGS) {
                 *shaderStr = fHeader;
                 shaderStr->append(fGSHeader);
                 this->appendDecls(fGSInputs, shaderStr);
                 this->appendDecls(fGSOutputs, shaderStr);
                 shaderStr->append("void main() {\n");
                 shaderStr->append(fGSCode);
                 shaderStr->append("}\n");
             } else {
                 shaderStr->reset();
             }
             break;
         case kFragment_ShaderType:
             *shaderStr = fHeader;
             append_default_precision_qualifier(kDefaultFragmentPrecision,
                                                fCtxInfo.binding(),
                                                shaderStr);
             shaderStr->append(fFSHeader);
             this->appendUniformDecls(kFragment_ShaderType, shaderStr);
             this->appendDecls(fFSInputs, shaderStr);
             // We shouldn't have declared outputs on 1.10
             GrAssert(k110_GrGLSLGeneration != fCtxInfo.glslGeneration() || fFSOutputs.empty());
             this->appendDecls(fFSOutputs, shaderStr);
             shaderStr->append(fFSFunctions);
             shaderStr->append("void main() {\n");
             shaderStr->append(fFSCode);
             shaderStr->append("}\n");
             break;
     }
  }

 void GrGLShaderBuilder::finished(GrGLuint programID) {
     fUniformManager.getUniformLocations(programID, fUniforms);
 }

 GrGLEffect* GrGLShaderBuilder::createAndEmitGLEffect(
                                 const GrEffectStage& stage,
                                 GrGLEffect::EffectKey key,
                                 const char* fsInColor,
                                 const char* fsOutColor,
                                 const char* vsInCoord,
                                 SkTArray<GrGLUniformManager::UniformHandle, true>* samplerHandles) {
     GrAssert(NULL != stage.getEffect());

     const GrEffectRef& effect = *stage.getEffect();
     int numTextures = effect->numTextures();
     SkSTArray<8, GrGLShaderBuilder::TextureSampler> textureSamplers;
     textureSamplers.push_back_n(numTextures);
     for (int i = 0; i < numTextures; ++i) {
         textureSamplers[i].init(this, &effect->textureAccess(i), i);
         samplerHandles->push_back(textureSamplers[i].fSamplerUniform);
     }

     GrGLEffect* glEffect = effect->getFactory().createGLInstance(effect);

     // Enclose custom code in a block to avoid namespace conflicts
     this->fVSCode.appendf("\t{ // %s\n", glEffect->name());
     this->fFSCode.appendf("\t{ // %s \n", glEffect->name());
     glEffect->emitCode(this,
                        stage,
                        key,
                        vsInCoord,
                        fsOutColor,
                        fsInColor,
                        textureSamplers);
     this->fVSCode.appendf("\t}\n");
     this->fFSCode.appendf("\t}\n");

     return glEffect;
 }
	/*
	* Copyright 2012 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "gl/GrGLShaderBuilder.h"
	#include "gl/GrGLProgram.h"
	#include "gl/GrGLUniformHandle.h"
	#include "GrTexture.h"

	// number of each input/output type in a single allocation block
	static const int kVarsPerBlock = 8;

	// except FS outputs where we expect 2 at most.
	static const int kMaxFSOutputs = 2;

	// ES2 FS only guarantees mediump and lowp support
	static const GrGLShaderVar::Precision kDefaultFragmentPrecision = GrGLShaderVar::kMedium_Precision;

	typedef GrGLUniformManager::UniformHandle UniformHandle;
	///////////////////////////////////////////////////////////////////////////////

	namespace {

	inline const char* sample_function_name(GrSLType type, GrGLSLGeneration glslGen) {
	if (kVec2f_GrSLType == type) {
	return glslGen >= k130_GrGLSLGeneration ? "texture" : "texture2D";
	} else {
	GrAssert(kVec3f_GrSLType == type);
	return glslGen >= k130_GrGLSLGeneration ? "textureProj" : "texture2DProj";
	}
	}

	/**
	* Do we need to either map r,g,b->a or a->r.
	*/
	inline bool swizzle_requires_alpha_remapping(const GrGLCaps& caps,
	const GrTextureAccess& access) {
	if (GrPixelConfigIsAlphaOnly(access.getTexture()->config())) {
	if (caps.textureRedSupport() && (GrTextureAccess::kA_SwizzleFlag & access.swizzleMask())) {
	return true;
	}
	if (GrTextureAccess::kRGB_SwizzleMask & access.swizzleMask()) {
	return true;
	}
	}
	return false;
	}

	void append_swizzle(SkString* outAppend,
	const GrTextureAccess& access,
	const GrGLCaps& caps) {
	const char* swizzle = access.getSwizzle();
	char mangledSwizzle[5];

	// The swizzling occurs using texture params instead of shader-mangling if ARB_texture_swizzle
	// is available.
	if (!caps.textureSwizzleSupport() && GrPixelConfigIsAlphaOnly(access.getTexture()->config())) {
	char alphaChar = caps.textureRedSupport() ? 'r' : 'a';
	int i;
	for (i = 0; '\0' != swizzle[i]; ++i) {
	mangledSwizzle[i] = alphaChar;
	}
	mangledSwizzle[i] ='\0';
	swizzle = mangledSwizzle;
	}
	// For shader prettiness we omit the swizzle rather than appending ".rgba".
	if (memcmp(swizzle, "rgba", 4)) {
	outAppend->appendf(".%s", swizzle);
	}
	}

	}

	///////////////////////////////////////////////////////////////////////////////

	// Architectural assumption: always 2-d input coords.
	// Likely to become non-constant and non-static, perhaps even
	// varying by stage, if we use 1D textures for gradients!
	//const int GrGLShaderBuilder::fCoordDims = 2;

	GrGLShaderBuilder::GrGLShaderBuilder(const GrGLContextInfo& ctxInfo,
	GrGLUniformManager& uniformManager)
	: fUniforms(kVarsPerBlock)
	, fVSAttrs(kVarsPerBlock)
	, fVSOutputs(kVarsPerBlock)
	, fGSInputs(kVarsPerBlock)
	, fGSOutputs(kVarsPerBlock)
	, fFSInputs(kVarsPerBlock)
	, fFSOutputs(kMaxFSOutputs)
	, fUsesGS(false)
	, fCtxInfo(ctxInfo)
	, fUniformManager(uniformManager)
	, fCurrentStageIdx(kNonStageIdx)
	, fSetupFragPosition(false)
	, fRTHeightUniform(GrGLUniformManager::kInvalidUniformHandle) {

	fPositionVar = &fVSAttrs.push_back();
	fPositionVar->set(kVec2f_GrSLType, GrGLShaderVar::kAttribute_TypeModifier, "aPosition");
	}

	void GrGLShaderBuilder::codeAppendf(ShaderType type, const char format[], va_list args) {
	SkString* string;
	switch (type) {
	case kVertex_ShaderType:
	string = &fVSCode;
	break;
	case kGeometry_ShaderType:
	string = &fGSCode;
	break;
	case kFragment_ShaderType:
	string = &fFSCode;
	break;
	default:
	GrCrash("Invalid shader type");
	}
	string->appendf(format, args);
	}

	void GrGLShaderBuilder::codeAppend(ShaderType type, const char* str) {
	SkString* string;
	switch (type) {
	case kVertex_ShaderType:
	string = &fVSCode;
	break;
	case kGeometry_ShaderType:
	string = &fGSCode;
	break;
	case kFragment_ShaderType:
	string = &fFSCode;
	break;
	default:
	GrCrash("Invalid shader type");
	}
	string->append(str);
	}

	void GrGLShaderBuilder::appendTextureLookup(SkString* out,
	const GrGLShaderBuilder::TextureSampler& sampler,
	const char* coordName,
	GrSLType varyingType) const {
	GrAssert(NULL != sampler.textureAccess());
	GrAssert(NULL != coordName);

	out->appendf("%s(%s, %s)",
	sample_function_name(varyingType, fCtxInfo.glslGeneration()),
	this->getUniformCStr(sampler.fSamplerUniform),
	coordName);
	append_swizzle(out, *sampler.textureAccess(), fCtxInfo.caps());
	}

	void GrGLShaderBuilder::appendTextureLookup(ShaderType type,
	const GrGLShaderBuilder::TextureSampler& sampler,
	const char* coordName,
	GrSLType varyingType) {
	GrAssert(kFragment_ShaderType == type);
	this->appendTextureLookup(&fFSCode, sampler, coordName, varyingType);
	}

	void GrGLShaderBuilder::appendTextureLookupAndModulate(
	ShaderType type,
	const char* modulation,
	const GrGLShaderBuilder::TextureSampler& sampler,
	const char* coordName,
	GrSLType varyingType) {
	GrAssert(kFragment_ShaderType == type);
	SkString lookup;
	this->appendTextureLookup(&lookup, sampler, coordName, varyingType);
	GrGLSLModulate4f(&fFSCode, modulation, lookup.c_str());
	}

	GrBackendEffectFactory::EffectKey GrGLShaderBuilder::KeyForTextureAccess(
	const GrTextureAccess& access,
	const GrGLCaps& caps) {
	GrBackendEffectFactory::EffectKey key = 0;

	// Assume that swizzle support implies that we never have to modify a shader to adjust
	// for texture format/swizzle settings.
	if (!caps.textureSwizzleSupport() && swizzle_requires_alpha_remapping(caps, access)) {
	key = 1;
	}
	#if GR_DEBUG
	// Assert that key is set iff the swizzle will be modified.
	SkString origString(access.getSwizzle());
	origString.prepend(".");
	SkString modifiedString;
	append_swizzle(&modifiedString, access, caps);
	if (!modifiedString.size()) {
	modifiedString = ".rgba";
	}
	GrAssert(SkToBool(key) == (modifiedString != origString));
	#endif
	return key;
	}

	const GrGLenum* GrGLShaderBuilder::GetTexParamSwizzle(GrPixelConfig config, const GrGLCaps& caps) {
	if (caps.textureSwizzleSupport() && GrPixelConfigIsAlphaOnly(config)) {
	if (caps.textureRedSupport()) {
	static const GrGLenum gRedSmear[] = { GR_GL_RED, GR_GL_RED, GR_GL_RED, GR_GL_RED };
	return gRedSmear;
	} else {
	static const GrGLenum gAlphaSmear[] = { GR_GL_ALPHA, GR_GL_ALPHA,
	GR_GL_ALPHA, GR_GL_ALPHA };
	return gAlphaSmear;
	}
	} else {
	static const GrGLenum gStraight[] = { GR_GL_RED, GR_GL_GREEN, GR_GL_BLUE, GR_GL_ALPHA };
	return gStraight;
	}
	}

	GrGLUniformManager::UniformHandle GrGLShaderBuilder::addUniformArray(uint32_t visibility,
	GrSLType type,
	const char* name,
	int count,
	const char** outName) {
	GrAssert(name && strlen(name));
	SkDEBUGCODE(static const uint32_t kVisibilityMask = kVertex_ShaderType \| kFragment_ShaderType);
	GrAssert(0 == (~kVisibilityMask & visibility));
	GrAssert(0 != visibility);

	BuilderUniform& uni = fUniforms.push_back();
	UniformHandle h = index_to_handle(fUniforms.count() - 1);
	GR_DEBUGCODE(UniformHandle h2 =)
	fUniformManager.appendUniform(type, count);
	// We expect the uniform manager to initially have no uniforms and that all uniforms are added
	// by this function. Therefore, the handles should match.
	GrAssert(h2 == h);
	uni.fVariable.setType(type);
	uni.fVariable.setTypeModifier(GrGLShaderVar::kUniform_TypeModifier);
	SkString* uniName = uni.fVariable.accessName();
	if (kNonStageIdx == fCurrentStageIdx) {
	uniName->printf("u%s", name);
	} else {
	uniName->printf("u%s%d", name, fCurrentStageIdx);
	}
	uni.fVariable.setArrayCount(count);
	uni.fVisibility = visibility;

	// If it is visible in both the VS and FS, the precision must match.
	// We declare a default FS precision, but not a default VS. So set the var
	// to use the default FS precision.
	if ((kVertex_ShaderType \| kFragment_ShaderType) == visibility) {
	// the fragment and vertex precisions must match
	uni.fVariable.setPrecision(kDefaultFragmentPrecision);
	}

	if (NULL != outName) {
	*outName = uni.fVariable.c_str();
	}

	return h;
	}

	const GrGLShaderVar& GrGLShaderBuilder::getUniformVariable(UniformHandle u) const {
	return fUniforms[handle_to_index(u)].fVariable;
	}

	void GrGLShaderBuilder::addVarying(GrSLType type,
	const char* name,
	const char** vsOutName,
	const char** fsInName) {
	fVSOutputs.push_back();
	fVSOutputs.back().setType(type);
	fVSOutputs.back().setTypeModifier(GrGLShaderVar::kOut_TypeModifier);
	if (kNonStageIdx == fCurrentStageIdx) {
	fVSOutputs.back().accessName()->printf("v%s", name);
	} else {
	fVSOutputs.back().accessName()->printf("v%s%d", name, fCurrentStageIdx);
	}
	if (vsOutName) {
	*vsOutName = fVSOutputs.back().getName().c_str();
	}
	// input to FS comes either from VS or GS
	const SkString* fsName;
	if (fUsesGS) {
	// if we have a GS take each varying in as an array
	// and output as non-array.
	fGSInputs.push_back();
	fGSInputs.back().setType(type);
	fGSInputs.back().setTypeModifier(GrGLShaderVar::kIn_TypeModifier);
	fGSInputs.back().setUnsizedArray();
	*fGSInputs.back().accessName() = fVSOutputs.back().getName();
	fGSOutputs.push_back();
	fGSOutputs.back().setType(type);
	fGSOutputs.back().setTypeModifier(GrGLShaderVar::kOut_TypeModifier);
	if (kNonStageIdx == fCurrentStageIdx) {
	fGSOutputs.back().accessName()->printf("g%s", name);
	} else {
	fGSOutputs.back().accessName()->printf("g%s%d", name, fCurrentStageIdx);
	}
	fsName = fGSOutputs.back().accessName();
	} else {
	fsName = fVSOutputs.back().accessName();
	}
	fFSInputs.push_back();
	fFSInputs.back().setType(type);
	fFSInputs.back().setTypeModifier(GrGLShaderVar::kIn_TypeModifier);
	fFSInputs.back().setName(*fsName);
	if (fsInName) {
	*fsInName = fsName->c_str();
	}
	}

	const char* GrGLShaderBuilder::fragmentPosition() {
	#if 1
	if (fCtxInfo.caps().fragCoordConventionsSupport()) {
	if (!fSetupFragPosition) {
	fFSHeader.append("#extension GL_ARB_fragment_coord_conventions: require\n");
	fFSInputs.push_back().set(kVec4f_GrSLType,
	GrGLShaderVar::kIn_TypeModifier,
	"gl_FragCoord",
	GrGLShaderVar::kDefault_Precision,
	GrGLShaderVar::kUpperLeft_Origin);
	fSetupFragPosition = true;
	}
	return "gl_FragCoord";
	} else {
	static const char* kCoordName = "fragCoordYDown";
	if (!fSetupFragPosition) {
	GrAssert(GrGLUniformManager::kInvalidUniformHandle == fRTHeightUniform);
	const char* rtHeightName;

	// temporarily change the stage index because we're inserting a uniform whose name
	// shouldn't be mangled to be stage-specific.
	int oldStageIdx = fCurrentStageIdx;
	fCurrentStageIdx = kNonStageIdx;
	fRTHeightUniform = this->addUniform(kFragment_ShaderType,
	kFloat_GrSLType,
	"RTHeight",
	&rtHeightName);
	fCurrentStageIdx = oldStageIdx;

	this->fFSCode.prependf("\tvec4 %s = vec4(gl_FragCoord.x, %s - gl_FragCoord.y, gl_FragCoord.zw);\n",
	kCoordName, rtHeightName);
	fSetupFragPosition = true;
	}
	GrAssert(GrGLUniformManager::kInvalidUniformHandle != fRTHeightUniform);
	return kCoordName;
	}
	#else
	// This is the path we'll need to use once we have support for TopLeft
	// render targets.
	if (!fSetupFragPosition) {
	fFSInputs.push_back().set(kVec4f_GrSLType,
	GrGLShaderVar::kIn_TypeModifier,
	"gl_FragCoord",
	GrGLShaderVar::kDefault_Precision);
	fSetupFragPosition = true;
	}
	return "gl_FragCoord";
	#endif
	}


	void GrGLShaderBuilder::emitFunction(ShaderType shader,
	GrSLType returnType,
	const char* name,
	int argCnt,
	const GrGLShaderVar* args,
	const char* body,
	SkString* outName) {
	GrAssert(kFragment_ShaderType == shader);
	fFSFunctions.append(GrGLShaderVar::TypeString(returnType));
	if (kNonStageIdx != fCurrentStageIdx) {
	outName->printf(" %s_%d", name, fCurrentStageIdx);
	} else {
	*outName = name;
	}
	fFSFunctions.append(*outName);
	fFSFunctions.append("(");
	for (int i = 0; i < argCnt; ++i) {
	args[i].appendDecl(fCtxInfo, &fFSFunctions);
	if (i < argCnt - 1) {
	fFSFunctions.append(", ");
	}
	}
	fFSFunctions.append(") {\n");
	fFSFunctions.append(body);
	fFSFunctions.append("}\n\n");
	}

	namespace {

	inline void append_default_precision_qualifier(GrGLShaderVar::Precision p,
	GrGLBinding binding,
	SkString* str) {
	// Desktop GLSL has added precision qualifiers but they don't do anything.
	if (kES2_GrGLBinding == binding) {
	switch (p) {
	case GrGLShaderVar::kHigh_Precision:
	str->append("precision highp float;\n");
	break;
	case GrGLShaderVar::kMedium_Precision:
	str->append("precision mediump float;\n");
	break;
	case GrGLShaderVar::kLow_Precision:
	str->append("precision lowp float;\n");
	break;
	case GrGLShaderVar::kDefault_Precision:
	GrCrash("Default precision now allowed.");
	default:
	GrCrash("Unknown precision value.");
	}
	}
	}
	}

	void GrGLShaderBuilder::appendDecls(const VarArray& vars, SkString* out) const {
	for (int i = 0; i < vars.count(); ++i) {
	vars[i].appendDecl(fCtxInfo, out);
	out->append(";\n");
	}
	}

	void GrGLShaderBuilder::appendUniformDecls(ShaderType stype, SkString* out) const {
	for (int i = 0; i < fUniforms.count(); ++i) {
	if (fUniforms[i].fVisibility & stype) {
	fUniforms[i].fVariable.appendDecl(fCtxInfo, out);
	out->append(";\n");
	}
	}
	}

	void GrGLShaderBuilder::getShader(ShaderType type, SkString* shaderStr) const {
	switch (type) {
	case kVertex_ShaderType:
	*shaderStr = fHeader;
	this->appendUniformDecls(kVertex_ShaderType, shaderStr);
	this->appendDecls(fVSAttrs, shaderStr);
	this->appendDecls(fVSOutputs, shaderStr);
	shaderStr->append("void main() {\n");
	shaderStr->append(fVSCode);
	shaderStr->append("}\n");
	break;
	case kGeometry_ShaderType:
	if (fUsesGS) {
	*shaderStr = fHeader;
	shaderStr->append(fGSHeader);
	this->appendDecls(fGSInputs, shaderStr);
	this->appendDecls(fGSOutputs, shaderStr);
	shaderStr->append("void main() {\n");
	shaderStr->append(fGSCode);
	shaderStr->append("}\n");
	} else {
	shaderStr->reset();
	}
	break;
	case kFragment_ShaderType:
	*shaderStr = fHeader;
	append_default_precision_qualifier(kDefaultFragmentPrecision,
	fCtxInfo.binding(),
	shaderStr);
	shaderStr->append(fFSHeader);
	this->appendUniformDecls(kFragment_ShaderType, shaderStr);
	this->appendDecls(fFSInputs, shaderStr);
	// We shouldn't have declared outputs on 1.10
	GrAssert(k110_GrGLSLGeneration != fCtxInfo.glslGeneration() \|\| fFSOutputs.empty());
	this->appendDecls(fFSOutputs, shaderStr);
	shaderStr->append(fFSFunctions);
	shaderStr->append("void main() {\n");
	shaderStr->append(fFSCode);
	shaderStr->append("}\n");
	break;
	}
	}

	void GrGLShaderBuilder::finished(GrGLuint programID) {
	fUniformManager.getUniformLocations(programID, fUniforms);
	}

	GrGLEffect* GrGLShaderBuilder::createAndEmitGLEffect(
	const GrEffectStage& stage,
	GrGLEffect::EffectKey key,
	const char* fsInColor,
	const char* fsOutColor,
	const char* vsInCoord,
	SkTArray<GrGLUniformManager::UniformHandle, true>* samplerHandles) {
	GrAssert(NULL != stage.getEffect());

	const GrEffectRef& effect = *stage.getEffect();
	int numTextures = effect->numTextures();
	SkSTArray<8, GrGLShaderBuilder::TextureSampler> textureSamplers;
	textureSamplers.push_back_n(numTextures);
	for (int i = 0; i < numTextures; ++i) {
	textureSamplers[i].init(this, &effect->textureAccess(i), i);
	samplerHandles->push_back(textureSamplers[i].fSamplerUniform);
	}

	GrGLEffect* glEffect = effect->getFactory().createGLInstance(effect);

	// Enclose custom code in a block to avoid namespace conflicts
	this->fVSCode.appendf("\t{ // %s\n", glEffect->name());
	this->fFSCode.appendf("\t{ // %s \n", glEffect->name());
	glEffect->emitCode(this,
	stage,
	key,
	vsInCoord,
	fsOutColor,
	fsInColor,
	textureSamplers);
	this->fVSCode.appendf("\t}\n");
	this->fFSCode.appendf("\t}\n");

	return glEffect;
	}