src/third_party/skia/src/gpu/gl/builders/GrGLProgramBuilder.cpp

/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "gl/GrGLProgram.h"
#include "gl/GrGLSLPrettyPrint.h"
#include "gl/GrGLUniformHandle.h"
#include "GrCoordTransform.h"
#include "../GrGpuGL.h"
#include "GrGLFragmentShaderBuilder.h"
#include "GrGLProgramBuilder.h"
#include "GrTexture.h"
#include "GrGLVertexShaderBuilder.h"
#include "SkRTConf.h"
#include "SkTraceEvent.h"

namespace {
#define GL_CALL(X) GR_GL_CALL(this->gpu()->glInterface(), X)
#define GL_CALL_RET(R, X) GR_GL_CALL_RET(this->gpu()->glInterface(), R, X)

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

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

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

bool GrGLProgramBuilder::genProgram(const GrGeometryStage* geometryProcessor,
                                    const GrFragmentStage* colorStages[],
                                    const GrFragmentStage* coverageStages[]) {
    const GrGLProgramDesc::KeyHeader& header = this->desc().getHeader();

    fFS.emitCodeBeforeEffects();

    ///////////////////////////////////////////////////////////////////////////
    // get the initial color and coverage to feed into the first effect in each effect chain

    GrGLSLExpr4 inputColor;
    GrGLSLExpr4 inputCoverage;

    if (GrGLProgramDesc::kUniform_ColorInput == header.fColorInput) {
        const char* name;
        fUniformHandles.fColorUni =
            this->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                             kVec4f_GrSLType,
                             "Color",
                             &name);
        inputColor = GrGLSLExpr4(name);
    } else if (GrGLProgramDesc::kAllOnes_ColorInput == header.fColorInput) {
        inputColor = GrGLSLExpr4(1);
    }

    if (GrGLProgramDesc::kUniform_ColorInput == header.fCoverageInput) {
        const char* name;
        fUniformHandles.fCoverageUni =
            this->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                             kVec4f_GrSLType,
                             "Coverage",
                             &name);
        inputCoverage = GrGLSLExpr4(name);
    } else if (GrGLProgramDesc::kAllOnes_ColorInput == header.fCoverageInput) {
        inputCoverage = GrGLSLExpr4(1);
    }

    // Subclasses drive effect emitting
    this->createAndEmitEffects(geometryProcessor, colorStages, coverageStages, &inputColor,
                               &inputCoverage);

    fFS.emitCodeAfterEffects(inputColor, inputCoverage);

    if (!this->finish()) {
        return false;
    }

    return true;
}

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

GrGLProgramBuilder::GrGLProgramBuilder(GrGpuGL* gpu,
                                       const GrGLProgramDesc& desc)
    : fEffectEmitter(NULL)
    , fFragOnly(SkToBool(desc.getHeader().fUseFragShaderOnly))
    , fTexCoordSetCnt(0)
    , fProgramID(0)
    , fFS(this, desc)
    , fSeparableVaryingInfos(kVarsPerBlock)
    , fGrProcessorEmitter(this)
    , fDesc(desc)
    , fGpu(gpu)
    , fUniforms(kVarsPerBlock) {
}

void GrGLProgramBuilder::nameVariable(SkString* out, char prefix, const char* name) {
    if ('\0' == prefix) {
        *out = name;
    } else {
        out->printf("%c%s", prefix, name);
    }
    if (fCodeStage.inStageCode()) {
        if (out->endsWith('_')) {
            // Names containing "__" are reserved.
            out->append("x");
        }
        out->appendf("_Stage%d", fCodeStage.stageIndex());
    }
}

GrGLProgramDataManager::UniformHandle GrGLProgramBuilder::addUniformArray(uint32_t visibility,
                                                                          GrSLType type,
                                                                          const char* name,
                                                                          int count,
                                                                          const char** outName) {
    SkASSERT(name && strlen(name));
    SkDEBUGCODE(static const uint32_t kVisibilityMask = kVertex_Visibility | kFragment_Visibility);
    SkASSERT(0 == (~kVisibilityMask & visibility));
    SkASSERT(0 != visibility);

    UniformInfo& uni = fUniforms.push_back();
    uni.fVariable.setType(type);
    uni.fVariable.setTypeModifier(GrGLShaderVar::kUniform_TypeModifier);
    this->nameVariable(uni.fVariable.accessName(), 'u', name);
    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_Visibility | kFragment_Visibility) == visibility) {
        // the fragment and vertex precisions must match
        uni.fVariable.setPrecision(kDefaultFragmentPrecision);
    }

    if (outName) {
        *outName = uni.fVariable.c_str();
    }
    return GrGLProgramDataManager::UniformHandle::CreateFromUniformIndex(fUniforms.count() - 1);
}

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

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

void GrGLProgramBuilder::createAndEmitEffects(const GrFragmentStage* effectStages[],
                                              int effectCnt,
                                              const GrGLProgramDesc::EffectKeyProvider& keyProvider,
                                              GrGLSLExpr4* fsInOutColor) {
    bool effectEmitted = false;

    GrGLSLExpr4 inColor = *fsInOutColor;
    GrGLSLExpr4 outColor;

    for (int e = 0; e < effectCnt; ++e) {
        fGrProcessorEmitter.set(effectStages[e]->getFragmentProcessor());
        fEffectEmitter = &fGrProcessorEmitter;
        // calls into the subclass to emit the actual effect into the program effect object
        this->emitEffect(*effectStages[e], e, keyProvider, &inColor, &outColor);
        effectEmitted = true;
    }

    if (effectEmitted) {
        *fsInOutColor = outColor;
    }
}

void GrGLProgramBuilder::emitEffect(const GrProcessorStage& effectStage,
                                    int effectIndex,
                                    const GrGLProgramDesc::EffectKeyProvider& keyProvider,
                                    GrGLSLExpr4* inColor,
                                    GrGLSLExpr4* outColor) {
    SkASSERT(effectStage.getProcessor());
    CodeStage::AutoStageRestore csar(&fCodeStage, &effectStage);

    if (inColor->isZeros()) {
        SkString inColorName;

        // Effects have no way to communicate zeros, they treat an empty string as ones.
        this->nameVariable(&inColorName, '\0', "input");
        fFS.codeAppendf("\tvec4 %s = %s;\n", inColorName.c_str(), inColor->c_str());
        *inColor = inColorName;
    }

    // create var to hold stage result
    SkString outColorName;
    this->nameVariable(&outColorName, '\0', "output");
    fFS.codeAppendf("\tvec4 %s;\n", outColorName.c_str());
    *outColor = outColorName;

    this->emitEffect(effectStage, keyProvider.get(effectIndex), outColor->c_str(),
                     inColor->isOnes() ? NULL : inColor->c_str(), fCodeStage.stageIndex());

    *inColor = *outColor;
}

void GrGLProgramBuilder::emitSamplers(const GrProcessor& effect,
                                      GrGLProcessor::TextureSamplerArray* outSamplers) {
    SkTArray<GrGLProgramEffects::Sampler, true>& samplers =
            this->getProgramEffects()->addSamplers();
    int numTextures = effect.numTextures();
    samplers.push_back_n(numTextures);
    SkString name;
    for (int t = 0; t < numTextures; ++t) {
        name.printf("Sampler%d", t);
        samplers[t].fUniform = this->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                                kSampler2D_GrSLType,
                                                name.c_str());
        SkNEW_APPEND_TO_TARRAY(outSamplers, GrGLProcessor::TextureSampler,
                               (samplers[t].fUniform, effect.textureAccess(t)));
    }
}

bool GrGLProgramBuilder::finish() {
    SkASSERT(0 == fProgramID);
    GL_CALL_RET(fProgramID, CreateProgram());
    if (!fProgramID) {
        return false;
    }

    SkTDArray<GrGLuint> shadersToDelete;

    if (!this->compileAndAttachShaders(fProgramID, &shadersToDelete)) {
        GL_CALL(DeleteProgram(fProgramID));
        return false;
    }

    this->bindProgramLocations(fProgramID);

    GL_CALL(LinkProgram(fProgramID));

    // Calling GetProgramiv is expensive in Chromium. Assume success in release builds.
    bool checkLinked = !fGpu->ctxInfo().isChromium();
#ifdef SK_DEBUG
    checkLinked = true;
#endif
    if (checkLinked) {
        GrGLint linked = GR_GL_INIT_ZERO;
        GL_CALL(GetProgramiv(fProgramID, GR_GL_LINK_STATUS, &linked));
        if (!linked) {
            GrGLint infoLen = GR_GL_INIT_ZERO;
            GL_CALL(GetProgramiv(fProgramID, GR_GL_INFO_LOG_LENGTH, &infoLen));
            SkAutoMalloc log(sizeof(char)*(infoLen+1));  // outside if for debugger
            if (infoLen > 0) {
                // retrieve length even though we don't need it to workaround
                // bug in chrome cmd buffer param validation.
                GrGLsizei length = GR_GL_INIT_ZERO;
                GL_CALL(GetProgramInfoLog(fProgramID,
                                          infoLen+1,
                                          &length,
                                          (char*)log.get()));
                GrPrintf((char*)log.get());
            }
            SkDEBUGFAIL("Error linking program");
            GL_CALL(DeleteProgram(fProgramID));
            fProgramID = 0;
            return false;
        }
    }

    this->resolveProgramLocations(fProgramID);

    for (int i = 0; i < shadersToDelete.count(); ++i) {
      GL_CALL(DeleteShader(shadersToDelete[i]));
    }

    return true;
}

bool GrGLProgramBuilder::compileAndAttachShaders(GrGLuint programId,
                                                 SkTDArray<GrGLuint>* shaderIds) const {
    return fFS.compileAndAttachShaders(programId, shaderIds);
}

void GrGLProgramBuilder::bindProgramLocations(GrGLuint programId) {
    fFS.bindProgramLocations(programId);

    // skbug.com/2056
    bool usingBindUniform = fGpu->glInterface()->fFunctions.fBindUniformLocation != NULL;
    if (usingBindUniform) {
        int count = fUniforms.count();
        for (int i = 0; i < count; ++i) {
            GL_CALL(BindUniformLocation(programId, i, fUniforms[i].fVariable.c_str()));
            fUniforms[i].fLocation = i;
        }
    }
}

void GrGLProgramBuilder::resolveProgramLocations(GrGLuint programId) {
    bool usingBindUniform = fGpu->glInterface()->fFunctions.fBindUniformLocation != NULL;
    if (!usingBindUniform) {
        int count = fUniforms.count();
        for (int i = 0; i < count; ++i) {
            GrGLint location;
            GL_CALL_RET(location,
                        GetUniformLocation(programId, fUniforms[i].fVariable.c_str()));
            fUniforms[i].fLocation = location;
        }
    }

    int count = fSeparableVaryingInfos.count();
    for (int i = 0; i < count; ++i) {
        GrGLint location;
        GL_CALL_RET(location,
                    GetProgramResourceLocation(programId,
                                               GR_GL_FRAGMENT_INPUT,
                                               fSeparableVaryingInfos[i].fVariable.c_str()));
        fSeparableVaryingInfos[i].fLocation = location;
    }
}

const GrGLContextInfo& GrGLProgramBuilder::ctxInfo() const {
    return fGpu->ctxInfo();
}