C++ TStructure类代码示例

void TOutputGLSLBase::writeVariableType(const TType &type)
{
    TInfoSinkBase &out = objSink();
    TQualifier qualifier = type.getQualifier();
    if (qualifier != EvqTemporary && qualifier != EvqGlobal)
    {
        out << type.getQualifierString() << " ";
    }
    // Declare the struct if we have not done so already.
    if (type.getBasicType() == EbtStruct && !structDeclared(type.getStruct()))
    {
        TStructure *structure = type.getStruct();

        declareStruct(structure);

        if (!structure->name().empty())
        {
            mDeclaredStructs.insert(structure->uniqueId());
        }
    }
    else
    {
        if (writeVariablePrecision(type.getPrecision()))
            out << " ";
        out << getTypeName(type);
    }
}

TString StructNameString(const TStructure &structure)
{
    if (structure.name().empty())
    {
        return "";
    }

    return "ss" + str(structure.uniqueId()) + "_" + structure.name();
}

void TOutputGLSLBase::writeVariableType(const TType &type)
{
    TInfoSinkBase &out = objSink();
    if (type.isInvariant())
    {
        out << "invariant ";
    }
    TQualifier qualifier = type.getQualifier();
    if (qualifier != EvqTemporary && qualifier != EvqGlobal)
    {
        if (IsGLSL130OrNewer(mOutput))
        {
            switch (qualifier)
            {
              case EvqAttribute:
                out << "in ";
                break;
              case EvqVaryingIn:
                out << "in ";
                break;
              case EvqVaryingOut:
                out << "out ";
                break;
              default:
                out << type.getQualifierString() << " ";
                break;
            }
        }
        else
        {
            out << type.getQualifierString() << " ";
        }
    }
    // Declare the struct if we have not done so already.
    if (type.getBasicType() == EbtStruct && !structDeclared(type.getStruct()))
    {
        TStructure *structure = type.getStruct();

        declareStruct(structure);

        if (!structure->name().empty())
        {
            mDeclaredStructs.insert(structure->uniqueId());
        }
    }
    else
    {
        if (writeVariablePrecision(type.getPrecision()))
            out << " ";
        out << getTypeName(type);
    }
}

TString QualifiedStructNameString(const TStructure &structure,
                                  bool useHLSLRowMajorPacking,
                                  bool useStd140Packing)
{
    if (structure.symbolType() == SymbolType::Empty)
    {
        return "";
    }

    TString prefix = "";

    // Structs packed with row-major matrices in HLSL are prefixed with "rm"
    // GLSL column-major maps to HLSL row-major, and the converse is true

    if (useStd140Packing)
    {
        prefix += "std_";
    }

    if (useHLSLRowMajorPacking)
    {
        prefix += "rm_";
    }

    return prefix + StructNameString(structure);
}

TString StructNameString(const TStructure &structure)
{
    if (structure.symbolType() == SymbolType::Empty)
    {
        return "";
    }

    // For structures at global scope we use a consistent
    // translation so that we can link between shader stages.
    if (structure.atGlobalScope())
    {
        return Decorate(structure.name());
    }

    return "ss" + str(structure.uniqueId().get()) + "_" + TString(structure.name().data());
}

TString DecorateField(const ImmutableString &string, const TStructure &structure)
{
    if (structure.symbolType() != SymbolType::BuiltIn)
    {
        return Decorate(string);
    }

    return TString(string.data());
}

TString DecorateField(const TString &string, const TStructure &structure)
{
    if (structure.name().compare(0, 3, "gl_") != 0)
    {
        return Decorate(string);
    }

    return string;
}

TString StructureHLSL::define(const TStructure &structure, bool useHLSLRowMajorPacking,
                              bool useStd140Packing, Std140PaddingHelper *padHelper)
{
    const TFieldList &fields = structure.fields();
    const bool isNameless = (structure.name() == "");
    const TString &structName = QualifiedStructNameString(structure, useHLSLRowMajorPacking,
                                                          useStd140Packing);
    const TString declareString = (isNameless ? "struct" : "struct " + structName);

    TString string;
    string += declareString + "\n"
              "{\n";

    for (unsigned int i = 0; i < fields.size(); i++)
    {
        const TField &field = *fields[i];
        const TType &fieldType = *field.type();
        const TStructure *fieldStruct = fieldType.getStruct();
        const TString &fieldTypeString = fieldStruct ?
                                         QualifiedStructNameString(*fieldStruct, useHLSLRowMajorPacking,
                                                                   useStd140Packing) :
                                         TypeString(fieldType);

        if (padHelper)
        {
            string += padHelper->prePaddingString(fieldType);
        }

        string += "    " + fieldTypeString + " " + DecorateField(field.name(), structure) + ArrayString(fieldType) + ";\n";

        if (padHelper)
        {
            string += padHelper->postPaddingString(fieldType, useHLSLRowMajorPacking);
        }
    }

    // Nameless structs do not finish with a semicolon and newline, to leave room for an instance variable
    string += (isNameless ? "} " : "};\n");

    return string;
}

void StructureHLSL::storeStd140ElementIndex(const TStructure &structure, bool useHLSLRowMajorPacking)
{
    Std140PaddingHelper padHelper = getPaddingHelper();
    const TFieldList &fields = structure.fields();

    for (unsigned int i = 0; i < fields.size(); i++)
    {
        padHelper.prePadding(*fields[i]->type());
    }

    // Add remaining element index to the global map, for use with nested structs in standard layouts
    const TString &structName = QualifiedStructNameString(structure, useHLSLRowMajorPacking, true);
    mStd140StructElementIndexes[structName] = padHelper.elementIndex();
}

void RegenerateStructNames::visitSymbol(TIntermSymbol *symbol)
{
    ASSERT(symbol);
    TType *type = symbol->getTypePointer();
    ASSERT(type);
    TStructure *userType = type->getStruct();
    if (!userType)
        return;

    if (mSymbolTable.findBuiltIn(userType->name(), mShaderVersion))
    {
        // Built-in struct, do not touch it.
        return;
    }

    int uniqueId = userType->uniqueId();

    ASSERT(mScopeDepth > 0);
    if (mScopeDepth == 1)
    {
        // If a struct is defined at global scope, we don't map its name.
        // This is because at global level, the struct might be used to
        // declare a uniform, so the same name needs to stay the same for
        // vertex/fragment shaders. However, our mapping uses internal ID,
        // which will be different for the same struct in vertex/fragment
        // shaders.
        // This is OK because names for any structs defined in other scopes
        // will begin with "_webgl", which is reserved. So there will be
        // no conflicts among unmapped struct names from global scope and
        // mapped struct names from other scopes.
        // However, we need to keep track of these global structs, so if a
        // variable is used in a local scope, we don't try to modify the
        // struct name through that variable.
        mDeclaredGlobalStructs.insert(uniqueId);
        return;
    }
    if (mDeclaredGlobalStructs.count(uniqueId) > 0)
        return;
    // Map {name} to _webgl_struct_{uniqueId}_{name}.
    const char kPrefix[] = "_webgl_struct_";
    if (userType->name().find(kPrefix) == 0)
    {
        // The name has already been regenerated.
        return;
    }
    std::string id = Str(uniqueId);
    TString tmp = kPrefix + TString(id.c_str());
    tmp += "_" + userType->name();
    userType->setName(tmp);
}

//.........这里部分代码省略.........
    if (type == GL_FRAGMENT_SHADER)
    {
        symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler2D, float3, int2, float1);
        symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler2D, float4, int2, float1);
        symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler3D, float4, int3, float1);
        symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjOffset", sampler2DShadow, float4, int2, float1);
    }

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureLodOffset", gsampler2D, float2, float1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureLodOffset", gsampler3D, float3, float1, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureLodOffset", sampler2DShadow, float3, float1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureLodOffset", gsampler2DArray, float3, float1, int2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLod", gsampler2D, float3, float1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLod", gsampler2D, float4, float1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLod", gsampler3D, float4, float1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjLod", sampler2DShadow, float4, float1);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLodOffset", gsampler2D, float3, float1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLodOffset", gsampler2D, float4, float1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLodOffset", gsampler3D, float4, float1, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjLodOffset", sampler2DShadow, float4, float1, int2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetch", gsampler2D, int2, int1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetch", gsampler3D, int3, int1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetch", gsampler2DArray, int3, int1);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetchOffset", gsampler2D, int2, int1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetchOffset", gsampler3D, int3, int1, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetchOffset", gsampler2DArray, int3, int1, int2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGrad", gsampler2D, float2, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGrad", gsampler3D, float3, float3, float3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGrad", gsamplerCube, float3, float3, float3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGrad", sampler2DShadow, float3, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGrad", samplerCubeShadow, float4, float3, float3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGrad", gsampler2DArray, float3, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGrad", sampler2DArrayShadow, float4, float2, float2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGradOffset", gsampler2D, float2, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGradOffset", gsampler3D, float3, float3, float3, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGradOffset", sampler2DShadow, float3, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGradOffset", gsampler2DArray, float3, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGradOffset", sampler2DArrayShadow, float4, float2, float2, int2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGrad", gsampler2D, float3, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGrad", gsampler2D, float4, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGrad", gsampler3D, float4, float3, float3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjGrad", sampler2DShadow, float4, float2, float2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGradOffset", gsampler2D, float3, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGradOffset", gsampler2D, float4, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGradOffset", gsampler3D, float4, float3, float3, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjGradOffset", sampler2DShadow, float4, float2, float2, int2);

    //
    // Depth range in window coordinates
    //
    TFieldList *fields = NewPoolTFieldList();
    TSourceLoc zeroSourceLoc = {0, 0, 0, 0};
    TField *near = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("near"), zeroSourceLoc);
    TField *far = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("far"), zeroSourceLoc);
    TField *diff = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("diff"), zeroSourceLoc);
    fields->push_back(near);
    fields->push_back(far);
    fields->push_back(diff);
    TStructure *depthRangeStruct = new TStructure(NewPoolTString("gl_DepthRangeParameters"), fields);
    TVariable *depthRangeParameters = new TVariable(&depthRangeStruct->name(), depthRangeStruct, true);
    symbolTable.insert(COMMON_BUILTINS, depthRangeParameters);
    TVariable *depthRange = new TVariable(NewPoolTString("gl_DepthRange"), TType(depthRangeStruct));
    depthRange->setQualifier(EvqUniform);
    symbolTable.insert(COMMON_BUILTINS, depthRange);

    //
    // Implementation dependent built-in constants.
    //
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxVertexAttribs", resources.MaxVertexAttribs);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxVertexUniformVectors", resources.MaxVertexUniformVectors);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxVertexTextureImageUnits", resources.MaxVertexTextureImageUnits);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxCombinedTextureImageUnits", resources.MaxCombinedTextureImageUnits);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxTextureImageUnits", resources.MaxTextureImageUnits);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxFragmentUniformVectors", resources.MaxFragmentUniformVectors);

    symbolTable.insertConstInt(ESSL1_BUILTINS, "gl_MaxVaryingVectors", resources.MaxVaryingVectors);

    {
        symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxDrawBuffers", resources.MaxDrawBuffers);
        if (resources.EXT_blend_func_extended)
        {
            symbolTable.insertConstIntExt(COMMON_BUILTINS, "GL_EXT_blend_func_extended",
                                          "gl_MaxDualSourceDrawBuffersEXT",
                                          resources.MaxDualSourceDrawBuffers);
        }
    }

    symbolTable.insertConstInt(ESSL3_BUILTINS, "gl_MaxVertexOutputVectors", resources.MaxVertexOutputVectors);
    symbolTable.insertConstInt(ESSL3_BUILTINS, "gl_MaxFragmentInputVectors", resources.MaxFragmentInputVectors);
    symbolTable.insertConstInt(ESSL3_BUILTINS, "gl_MinProgramTexelOffset", resources.MinProgramTexelOffset);
    symbolTable.insertConstInt(ESSL3_BUILTINS, "gl_MaxProgramTexelOffset", resources.MaxProgramTexelOffset);
}

//.........这里部分代码省略.........
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler2D, float3, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler2D, float4, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler3D, float4, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjOffset", sampler2DShadow, float4, int2);

    if(type == SH_FRAGMENT_SHADER)
    {
        symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler2D, float3, int2, float1);
        symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler2D, float4, int2, float1);
        symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjOffset", gsampler3D, float4, int3, float1);
        symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjOffset", sampler2DShadow, float4, int2, float1);
    }

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureLodOffset", gsampler2D, float2, float1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureLodOffset", gsampler3D, float3, float1, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureLodOffset", sampler2DShadow, float3, float1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureLodOffset", gsampler2DArray, float3, float1, int2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLod", gsampler2D, float3, float1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLod", gsampler2D, float4, float1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLod", gsampler3D, float4, float1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjLod", sampler2DShadow, float4, float1);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLodOffset", gsampler2D, float3, float1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLodOffset", gsampler2D, float4, float1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjLodOffset", gsampler3D, float4, float1, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjLodOffset", sampler2DShadow, float4, float1, int2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetch", gsampler2D, int2, int1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetch", gsampler3D, int3, int1);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetch", gsampler2DArray, int3, int1);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetchOffset", gsampler2D, int2, int1, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetchOffset", gsampler3D, int3, int1, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "texelFetchOffset", gsampler2DArray, int3, int1, int2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGrad", gsampler2D, float2, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGrad", gsampler3D, float3, float3, float3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGrad", gsamplerCube, float3, float3, float3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGrad", sampler2DShadow, float3, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGrad", samplerCubeShadow, float4, float3, float3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGrad", gsampler2DArray, float3, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGrad", sampler2DArrayShadow, float4, float2, float2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGradOffset", gsampler2D, float2, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGradOffset", gsampler3D, float3, float3, float3, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGradOffset", sampler2DShadow, float3, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureGradOffset", gsampler2DArray, float3, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureGradOffset", sampler2DArrayShadow, float4, float2, float2, int2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGrad", gsampler2D, float3, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGrad", gsampler2D, float4, float2, float2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGrad", gsampler3D, float4, float3, float3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjGrad", sampler2DShadow, float4, float2, float2);

    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGradOffset", gsampler2D, float3, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGradOffset", gsampler2D, float4, float2, float2, int2);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, gvec4, "textureProjGradOffset", gsampler3D, float4, float3, float3, int3);
    symbolTable.insertBuiltIn(ESSL3_BUILTINS, float1, "textureProjGradOffset", sampler2DShadow, float4, float2, float2, int2);

    //
    // Depth range in window coordinates
    //
    TFieldList *fields = NewPoolTFieldList();
    TSourceLoc zeroSourceLoc = {0, 0, 0, 0};
    TField *near = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("near"), zeroSourceLoc);
    TField *far = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("far"), zeroSourceLoc);
    TField *diff = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("diff"), zeroSourceLoc);
    fields->push_back(near);
    fields->push_back(far);
    fields->push_back(diff);
    TStructure *depthRangeStruct = new TStructure(NewPoolTString("gl_DepthRangeParameters"), fields);
    TVariable *depthRangeParameters = new TVariable(&depthRangeStruct->name(), depthRangeStruct, true);
    symbolTable.insert(COMMON_BUILTINS, *depthRangeParameters);
    TVariable *depthRange = new TVariable(NewPoolTString("gl_DepthRange"), TType(depthRangeStruct));
    depthRange->setQualifier(EvqUniform);
    symbolTable.insert(COMMON_BUILTINS, *depthRange);

    //
    // Implementation dependent built-in constants.
    //
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxVertexAttribs", resources.MaxVertexAttribs);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxVertexUniformVectors", resources.MaxVertexUniformVectors);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxVertexTextureImageUnits", resources.MaxVertexTextureImageUnits);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxCombinedTextureImageUnits", resources.MaxCombinedTextureImageUnits);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxTextureImageUnits", resources.MaxTextureImageUnits);
    symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxFragmentUniformVectors", resources.MaxFragmentUniformVectors);

    symbolTable.insertConstInt(ESSL1_BUILTINS, "gl_MaxVaryingVectors", resources.MaxVaryingVectors);

    if (spec != SH_CSS_SHADERS_SPEC)
    {
        symbolTable.insertConstInt(COMMON_BUILTINS, "gl_MaxDrawBuffers", resources.MaxDrawBuffers);
    }

    symbolTable.insertConstInt(ESSL3_BUILTINS, "gl_MaxVertexOutputVectors", resources.MaxVertexOutputVectors);
    symbolTable.insertConstInt(ESSL3_BUILTINS, "gl_MaxFragmentInputVectors", resources.MaxFragmentInputVectors);
    symbolTable.insertConstInt(ESSL3_BUILTINS, "gl_MinProgramTexelOffset", resources.MinProgramTexelOffset);
    symbolTable.insertConstInt(ESSL3_BUILTINS, "gl_MaxProgramTexelOffset", resources.MaxProgramTexelOffset);
}

//.........这里部分代码省略.........
    symbolTable.insertBuiltIn(bool2, "not", bool2);
    symbolTable.insertBuiltIn(bool3, "not", bool3);
    symbolTable.insertBuiltIn(bool4, "not", bool4);

    TType *sampler2D = new TType(EbtSampler2D, EbpUndefined, EvqGlobal, 1);
    TType *samplerCube = new TType(EbtSamplerCube, EbpUndefined, EvqGlobal, 1);

    //
    // Texture Functions for GLSL ES 1.0
    //
    symbolTable.insertBuiltIn(float4, "texture2D", sampler2D, float2);
    symbolTable.insertBuiltIn(float4, "texture2DProj", sampler2D, float3);
    symbolTable.insertBuiltIn(float4, "texture2DProj", sampler2D, float4);
    symbolTable.insertBuiltIn(float4, "textureCube", samplerCube, float3);

    if (resources.OES_EGL_image_external)
    {
        TType *samplerExternalOES = new TType(EbtSamplerExternalOES, EbpUndefined, EvqGlobal, 1);

        symbolTable.insertBuiltIn(float4, "texture2D", samplerExternalOES, float2);
        symbolTable.insertBuiltIn(float4, "texture2DProj", samplerExternalOES, float3);
        symbolTable.insertBuiltIn(float4, "texture2DProj", samplerExternalOES, float4);
    }

    if (resources.ARB_texture_rectangle)
    {
        TType *sampler2DRect = new TType(EbtSampler2DRect, EbpUndefined, EvqGlobal, 1);

        symbolTable.insertBuiltIn(float4, "texture2DRect", sampler2DRect, float2);
        symbolTable.insertBuiltIn(float4, "texture2DRectProj", sampler2DRect, float3);
        symbolTable.insertBuiltIn(float4, "texture2DRectProj", sampler2DRect, float4);
    }

    if (type == SH_FRAGMENT_SHADER)
    {
        symbolTable.insertBuiltIn(float4, "texture2D", sampler2D, float2, float1);
        symbolTable.insertBuiltIn(float4, "texture2DProj", sampler2D, float3, float1);
        symbolTable.insertBuiltIn(float4, "texture2DProj", sampler2D, float4, float1);
        symbolTable.insertBuiltIn(float4, "textureCube", samplerCube, float3, float1);

        if (resources.OES_standard_derivatives)
        {
            symbolTable.insertBuiltIn(float1, "dFdx", float1);
            symbolTable.insertBuiltIn(float2, "dFdx", float2);
            symbolTable.insertBuiltIn(float3, "dFdx", float3);
            symbolTable.insertBuiltIn(float4, "dFdx", float4);
            
            symbolTable.insertBuiltIn(float1, "dFdy", float1);
            symbolTable.insertBuiltIn(float2, "dFdy", float2);
            symbolTable.insertBuiltIn(float3, "dFdy", float3);
            symbolTable.insertBuiltIn(float4, "dFdy", float4);

            symbolTable.insertBuiltIn(float1, "fwidth", float1);
            symbolTable.insertBuiltIn(float2, "fwidth", float2);
            symbolTable.insertBuiltIn(float3, "fwidth", float3);
            symbolTable.insertBuiltIn(float4, "fwidth", float4);
        }
    }

    if(type == SH_VERTEX_SHADER)
    {
        symbolTable.insertBuiltIn(float4, "texture2DLod", sampler2D, float2, float1);
        symbolTable.insertBuiltIn(float4, "texture2DProjLod", sampler2D, float3, float1);
        symbolTable.insertBuiltIn(float4, "texture2DProjLod", sampler2D, float4, float1);
        symbolTable.insertBuiltIn(float4, "textureCubeLod", samplerCube, float3, float1);
    }

    //
    // Depth range in window coordinates
    //
    TFieldList *fields = NewPoolTFieldList();
    TField *near = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("near"));
    TField *far = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("far"));
    TField *diff = new TField(new TType(EbtFloat, EbpHigh, EvqGlobal, 1), NewPoolTString("diff"));
    fields->push_back(near);
    fields->push_back(far);
    fields->push_back(diff);
    TStructure *depthRangeStruct = new TStructure(NewPoolTString("gl_DepthRangeParameters"), fields);
    TVariable *depthRangeParameters = new TVariable(&depthRangeStruct->name(), depthRangeStruct, true);
    symbolTable.insert(*depthRangeParameters);
    TVariable *depthRange = new TVariable(NewPoolTString("gl_DepthRange"), TType(depthRangeStruct));
    depthRange->setQualifier(EvqUniform);
    symbolTable.insert(*depthRange);

    //
    // Implementation dependent built-in constants.
    //
    symbolTable.insertConstInt("gl_MaxVertexAttribs", resources.MaxVertexAttribs);
    symbolTable.insertConstInt("gl_MaxVertexUniformVectors", resources.MaxVertexUniformVectors);
    symbolTable.insertConstInt("gl_MaxVaryingVectors", resources.MaxVaryingVectors);
    symbolTable.insertConstInt("gl_MaxVertexTextureImageUnits", resources.MaxVertexTextureImageUnits);
    symbolTable.insertConstInt("gl_MaxCombinedTextureImageUnits", resources.MaxCombinedTextureImageUnits);
    symbolTable.insertConstInt("gl_MaxTextureImageUnits", resources.MaxTextureImageUnits);
    symbolTable.insertConstInt("gl_MaxFragmentUniformVectors", resources.MaxFragmentUniformVectors);

    if (spec != SH_CSS_SHADERS_SPEC)
    {
        symbolTable.insertConstInt("gl_MaxDrawBuffers", resources.MaxDrawBuffers);
    }
}

bool TStructure::equals(const TStructure &other) const
{
    return (uniqueId() == other.uniqueId());
}

TIntermTyped *CreateZeroNode(const TType &type)
{
    TType constType(type);
    constType.setQualifier(EvqConst);

    if (!type.isArray() && type.getBasicType() != EbtStruct)
    {
        size_t size       = constType.getObjectSize();
        TConstantUnion *u = new TConstantUnion[size];
        for (size_t i = 0; i < size; ++i)
        {
            switch (type.getBasicType())
            {
                case EbtFloat:
                    u[i].setFConst(0.0f);
                    break;
                case EbtInt:
                    u[i].setIConst(0);
                    break;
                case EbtUInt:
                    u[i].setUConst(0u);
                    break;
                case EbtBool:
                    u[i].setBConst(false);
                    break;
                default:
                    // CreateZeroNode is called by ParseContext that keeps parsing even when an
                    // error occurs, so it is possible for CreateZeroNode to be called with
                    // non-basic types. This happens only on error condition but CreateZeroNode
                    // needs to return a value with the correct type to continue the typecheck.
                    // That's why we handle non-basic type by setting whatever value, we just need
                    // the type to be right.
                    u[i].setIConst(42);
                    break;
            }
        }

        TIntermConstantUnion *node = new TIntermConstantUnion(u, constType);
        return node;
    }

    if (type.getBasicType() == EbtVoid)
    {
        // Void array. This happens only on error condition, similarly to the case above. We don't
        // have a constructor operator for void, so this needs special handling. We'll end up with a
        // value without the array type, but that should not be a problem.
        while (constType.isArray())
        {
            constType.toArrayElementType();
        }
        return CreateZeroNode(constType);
    }

    TIntermSequence *arguments = new TIntermSequence();

    if (type.isArray())
    {
        TType elementType(type);
        elementType.toArrayElementType();

        size_t arraySize = type.getOutermostArraySize();
        for (size_t i = 0; i < arraySize; ++i)
        {
            arguments->push_back(CreateZeroNode(elementType));
        }
    }
    else
    {
        ASSERT(type.getBasicType() == EbtStruct);

        TStructure *structure = type.getStruct();
        for (const auto &field : structure->fields())
        {
            arguments->push_back(CreateZeroNode(*field->type()));
        }
    }

    return TIntermAggregate::CreateConstructor(constType, arguments);
}