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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 #include "GrShaderVar.h"
      9 #include "GrShaderCaps.h"
     10 #include "GrSwizzle.h"
     11 #include "glsl/GrGLSLShaderBuilder.h"
     12 #include "glsl/GrGLSLColorSpaceXformHelper.h"
     13 #include "glsl/GrGLSLProgramBuilder.h"
     14 
     15 GrGLSLShaderBuilder::GrGLSLShaderBuilder(GrGLSLProgramBuilder* program)
     16     : fProgramBuilder(program)
     17     , fInputs(GrGLSLProgramBuilder::kVarsPerBlock)
     18     , fOutputs(GrGLSLProgramBuilder::kVarsPerBlock)
     19     , fFeaturesAddedMask(0)
     20     , fCodeIndex(kCode)
     21     , fFinalized(false) {
     22     // We push back some dummy pointers which will later become our header
     23     for (int i = 0; i <= kCode; i++) {
     24         fShaderStrings.push_back();
     25         fCompilerStrings.push_back(nullptr);
     26         fCompilerStringLengths.push_back(0);
     27     }
     28 
     29     this->main() = "void main() {";
     30 }
     31 
     32 void GrGLSLShaderBuilder::declAppend(const GrShaderVar& var) {
     33     SkString tempDecl;
     34     var.appendDecl(fProgramBuilder->shaderCaps(), &tempDecl);
     35     this->codeAppendf("%s;", tempDecl.c_str());
     36 }
     37 
     38 void GrGLSLShaderBuilder::declareGlobal(const GrShaderVar& v) {
     39     v.appendDecl(this->getProgramBuilder()->shaderCaps(), &this->definitions());
     40     this->definitions().append(";");
     41 }
     42 
     43 void GrGLSLShaderBuilder::emitFunction(GrSLType returnType,
     44                                        const char* name,
     45                                        int argCnt,
     46                                        const GrShaderVar* args,
     47                                        const char* body,
     48                                        SkString* outName) {
     49     this->functions().append(GrGLSLTypeString(returnType));
     50     fProgramBuilder->nameVariable(outName, '\0', name);
     51     this->functions().appendf(" %s", outName->c_str());
     52     this->functions().append("(");
     53     for (int i = 0; i < argCnt; ++i) {
     54         args[i].appendDecl(fProgramBuilder->shaderCaps(), &this->functions());
     55         if (i < argCnt - 1) {
     56             this->functions().append(", ");
     57         }
     58     }
     59     this->functions().append(") {\n");
     60     this->functions().append(body);
     61     this->functions().append("}\n\n");
     62 }
     63 
     64 static inline void append_texture_swizzle(SkString* out, GrSwizzle swizzle) {
     65     if (swizzle != GrSwizzle::RGBA()) {
     66         out->appendf(".%s", swizzle.c_str());
     67     }
     68 }
     69 
     70 void GrGLSLShaderBuilder::appendTextureLookup(SkString* out,
     71                                               SamplerHandle samplerHandle,
     72                                               const char* coordName,
     73                                               GrSLType varyingType) const {
     74     const GrShaderVar& sampler = fProgramBuilder->samplerVariable(samplerHandle);
     75     out->appendf("texture(%s, %s)", sampler.c_str(), coordName);
     76     append_texture_swizzle(out, fProgramBuilder->samplerSwizzle(samplerHandle));
     77 }
     78 
     79 void GrGLSLShaderBuilder::appendTextureLookup(SamplerHandle samplerHandle,
     80                                               const char* coordName,
     81                                               GrSLType varyingType,
     82                                               GrGLSLColorSpaceXformHelper* colorXformHelper) {
     83     if (colorXformHelper && colorXformHelper->isValid()) {
     84         // With a color gamut transform, we need to wrap the lookup in another function call
     85         SkString lookup;
     86         this->appendTextureLookup(&lookup, samplerHandle, coordName, varyingType);
     87         this->appendColorGamutXform(lookup.c_str(), colorXformHelper);
     88     } else {
     89         this->appendTextureLookup(&this->code(), samplerHandle, coordName, varyingType);
     90     }
     91 }
     92 
     93 void GrGLSLShaderBuilder::appendTextureLookupAndModulate(
     94                                                     const char* modulation,
     95                                                     SamplerHandle samplerHandle,
     96                                                     const char* coordName,
     97                                                     GrSLType varyingType,
     98                                                     GrGLSLColorSpaceXformHelper* colorXformHelper) {
     99     SkString lookup;
    100     this->appendTextureLookup(&lookup, samplerHandle, coordName, varyingType);
    101     if (colorXformHelper && colorXformHelper->isValid()) {
    102         SkString xform;
    103         this->appendColorGamutXform(&xform, lookup.c_str(), colorXformHelper);
    104         if (modulation) {
    105             this->codeAppendf("%s * %s", modulation, xform.c_str());
    106         } else {
    107             this->codeAppendf("%s", xform.c_str());
    108         }
    109     } else {
    110         if (modulation) {
    111             this->codeAppendf("%s * %s", modulation, lookup.c_str());
    112         } else {
    113             this->codeAppendf("%s", lookup.c_str());
    114         }
    115     }
    116 }
    117 
    118 void GrGLSLShaderBuilder::appendColorGamutXform(SkString* out,
    119                                                 const char* srcColor,
    120                                                 GrGLSLColorSpaceXformHelper* colorXformHelper) {
    121     // Our color is (r, g, b, a), but we want to multiply (r, g, b, 1) by our matrix, then
    122     // re-insert the original alpha. The supplied srcColor is likely to be of the form
    123     // "texture(...)", and we don't want to evaluate that twice, so wrap everything in a function.
    124     static const GrShaderVar gColorGamutXformArgs[] = {
    125         GrShaderVar("color", kVec4f_GrSLType),
    126         GrShaderVar("xform", kMat44f_GrSLType),
    127     };
    128     SkString functionBody;
    129     // Gamut xform, clamp to destination gamut. We only support/have premultiplied textures, so we
    130     // always just clamp to alpha.
    131     functionBody.append("\tcolor.rgb = clamp((xform * vec4(color.rgb, 1.0)).rgb, 0.0, color.a);\n");
    132     functionBody.append("\treturn color;");
    133     SkString colorGamutXformFuncName;
    134     this->emitFunction(kVec4f_GrSLType,
    135                        "colorGamutXform",
    136                        SK_ARRAY_COUNT(gColorGamutXformArgs),
    137                        gColorGamutXformArgs,
    138                        functionBody.c_str(),
    139                        &colorGamutXformFuncName);
    140 
    141     GrGLSLUniformHandler* uniformHandler = fProgramBuilder->uniformHandler();
    142     out->appendf("%s(%s, %s)", colorGamutXformFuncName.c_str(), srcColor,
    143                  uniformHandler->getUniformCStr(colorXformHelper->gamutXformUniform()));
    144 }
    145 
    146 void GrGLSLShaderBuilder::appendColorGamutXform(const char* srcColor,
    147                                                 GrGLSLColorSpaceXformHelper* colorXformHelper) {
    148     SkString xform;
    149     this->appendColorGamutXform(&xform, srcColor, colorXformHelper);
    150     this->codeAppend(xform.c_str());
    151 }
    152 
    153 void GrGLSLShaderBuilder::appendTexelFetch(SkString* out,
    154                                            TexelBufferHandle texelBufferHandle,
    155                                            const char* coordExpr) const {
    156     const GrShaderVar& texelBuffer = fProgramBuilder->texelBufferVariable(texelBufferHandle);
    157     SkASSERT(fProgramBuilder->shaderCaps()->texelFetchSupport());
    158 
    159     out->appendf("texelFetch(%s, %s)", texelBuffer.c_str(), coordExpr);
    160 }
    161 
    162 void GrGLSLShaderBuilder::appendTexelFetch(TexelBufferHandle texelBufferHandle,
    163                                            const char* coordExpr) {
    164     this->appendTexelFetch(&this->code(), texelBufferHandle, coordExpr);
    165 }
    166 
    167 void GrGLSLShaderBuilder::appendImageStorageLoad(SkString* out, ImageStorageHandle handle,
    168                                                  const char* coordExpr) {
    169     const GrShaderVar& imageStorage = fProgramBuilder->imageStorageVariable(handle);
    170     out->appendf("imageLoad(%s, %s)", imageStorage.c_str(), coordExpr);
    171 }
    172 
    173 void GrGLSLShaderBuilder::appendImageStorageLoad(ImageStorageHandle handle, const char* coordExpr) {
    174     this->appendImageStorageLoad(&this->code(), handle, coordExpr);
    175 }
    176 
    177 bool GrGLSLShaderBuilder::addFeature(uint32_t featureBit, const char* extensionName) {
    178     if (featureBit & fFeaturesAddedMask) {
    179         return false;
    180     }
    181     this->extensions().appendf("#extension %s: require\n", extensionName);
    182     fFeaturesAddedMask |= featureBit;
    183     return true;
    184 }
    185 
    186 void GrGLSLShaderBuilder::appendDecls(const VarArray& vars, SkString* out) const {
    187     for (int i = 0; i < vars.count(); ++i) {
    188         vars[i].appendDecl(fProgramBuilder->shaderCaps(), out);
    189         out->append(";\n");
    190     }
    191 }
    192 
    193 void GrGLSLShaderBuilder::addLayoutQualifier(const char* param, InterfaceQualifier interface) {
    194     SkASSERT(fProgramBuilder->shaderCaps()->generation() >= k330_GrGLSLGeneration ||
    195              fProgramBuilder->shaderCaps()->mustEnableAdvBlendEqs());
    196     fLayoutParams[interface].push_back() = param;
    197 }
    198 
    199 void GrGLSLShaderBuilder::compileAndAppendLayoutQualifiers() {
    200     static const char* interfaceQualifierNames[] = {
    201         "in",
    202         "out"
    203     };
    204 
    205     for (int interface = 0; interface <= kLastInterfaceQualifier; ++interface) {
    206         const SkTArray<SkString>& params = fLayoutParams[interface];
    207         if (params.empty()) {
    208             continue;
    209         }
    210         this->layoutQualifiers().appendf("layout(%s", params[0].c_str());
    211         for (int i = 1; i < params.count(); ++i) {
    212             this->layoutQualifiers().appendf(", %s", params[i].c_str());
    213         }
    214         this->layoutQualifiers().appendf(") %s;\n", interfaceQualifierNames[interface]);
    215     }
    216 
    217     GR_STATIC_ASSERT(0 == GrGLSLShaderBuilder::kIn_InterfaceQualifier);
    218     GR_STATIC_ASSERT(1 == GrGLSLShaderBuilder::kOut_InterfaceQualifier);
    219     GR_STATIC_ASSERT(SK_ARRAY_COUNT(interfaceQualifierNames) == kLastInterfaceQualifier + 1);
    220 }
    221 
    222 void GrGLSLShaderBuilder::finalize(uint32_t visibility) {
    223     SkASSERT(!fFinalized);
    224     this->versionDecl() = fProgramBuilder->shaderCaps()->versionDeclString();
    225     this->compileAndAppendLayoutQualifiers();
    226     SkASSERT(visibility);
    227     fProgramBuilder->appendUniformDecls((GrShaderFlags) visibility, &this->uniforms());
    228     this->appendDecls(fInputs, &this->inputs());
    229     this->appendDecls(fOutputs, &this->outputs());
    230     this->onFinalize();
    231     // append the 'footer' to code
    232     this->code().append("}");
    233 
    234     for (int i = 0; i <= fCodeIndex; i++) {
    235         fCompilerStrings[i] = fShaderStrings[i].c_str();
    236         fCompilerStringLengths[i] = (int)fShaderStrings[i].size();
    237     }
    238 
    239     fFinalized = true;
    240 }
    241