michael@0: //
michael@0: // Copyright (c) 2002-2011 The ANGLE Project Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: //
michael@0: 
michael@0: #include "compiler/BuiltInFunctionEmulator.h"
michael@0: 
michael@0: #include "compiler/SymbolTable.h"
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: // we use macros here instead of function definitions to work around more GLSL
michael@0: // compiler bugs, in particular on NVIDIA hardware on Mac OSX. Macros are
michael@0: // problematic because if the argument has side-effects they will be repeatedly
michael@0: // evaluated. This is unlikely to show up in real shaders, but is something to
michael@0: // consider.
michael@0: const char* kFunctionEmulationVertexSource[] = {
michael@0:     "#error no emulation for cos(float)",
michael@0:     "#error no emulation for cos(vec2)",
michael@0:     "#error no emulation for cos(vec3)",
michael@0:     "#error no emulation for cos(vec4)",
michael@0: 
michael@0:     "#define webgl_distance_emu(x, y) ((x) >= (y) ? (x) - (y) : (y) - (x))",
michael@0:     "#error no emulation for distance(vec2, vec2)",
michael@0:     "#error no emulation for distance(vec3, vec3)",
michael@0:     "#error no emulation for distance(vec4, vec4)",
michael@0: 
michael@0:     "#define webgl_dot_emu(x, y) ((x) * (y))",
michael@0:     "#error no emulation for dot(vec2, vec2)",
michael@0:     "#error no emulation for dot(vec3, vec3)",
michael@0:     "#error no emulation for dot(vec4, vec4)",
michael@0: 
michael@0:     // |faceforward(N, I, Nref)| is |dot(NRef, I) < 0 ? N : -N|
michael@0:     "#define webgl_faceforward_emu(N, I, Nref) (((Nref) * (I) < 0.0) ? (N) : -(N))",
michael@0:     "#error no emulation for faceforward(vec2, vec2, vec2)",
michael@0:     "#error no emulation for faceforward(vec3, vec3, vec3)",
michael@0:     "#error no emulation for faceforward(vec4, vec4, vec4)",
michael@0: 
michael@0:     "#define webgl_length_emu(x) ((x) >= 0.0 ? (x) : -(x))",
michael@0:     "#error no emulation for length(vec2)",
michael@0:     "#error no emulation for length(vec3)",
michael@0:     "#error no emulation for length(vec4)",
michael@0: 
michael@0:     "#define webgl_normalize_emu(x) ((x) == 0.0 ? 0.0 : ((x) > 0.0 ? 1.0 : -1.0))",
michael@0:     "#error no emulation for normalize(vec2)",
michael@0:     "#error no emulation for normalize(vec3)",
michael@0:     "#error no emulation for normalize(vec4)",
michael@0: 
michael@0:     "#define webgl_reflect_emu(I, N) ((I) - 2.0 * (N) * (I) * (N))",
michael@0:     "#error no emulation for reflect(vec2, vec2)",
michael@0:     "#error no emulation for reflect(vec3, vec3)",
michael@0:     "#error no emulation for reflect(vec4, vec4)"
michael@0: };
michael@0: 
michael@0: const char* kFunctionEmulationFragmentSource[] = {
michael@0:     "webgl_emu_precision float webgl_cos_emu(webgl_emu_precision float a) { return cos(a); }",
michael@0:     "webgl_emu_precision vec2 webgl_cos_emu(webgl_emu_precision vec2 a) { return cos(a); }",
michael@0:     "webgl_emu_precision vec3 webgl_cos_emu(webgl_emu_precision vec3 a) { return cos(a); }",
michael@0:     "webgl_emu_precision vec4 webgl_cos_emu(webgl_emu_precision vec4 a) { return cos(a); }",
michael@0: 
michael@0:     "#define webgl_distance_emu(x, y) ((x) >= (y) ? (x) - (y) : (y) - (x))",
michael@0:     "#error no emulation for distance(vec2, vec2)",
michael@0:     "#error no emulation for distance(vec3, vec3)",
michael@0:     "#error no emulation for distance(vec4, vec4)",
michael@0: 
michael@0:     "#define webgl_dot_emu(x, y) ((x) * (y))",
michael@0:     "#error no emulation for dot(vec2, vec2)",
michael@0:     "#error no emulation for dot(vec3, vec3)",
michael@0:     "#error no emulation for dot(vec4, vec4)",
michael@0: 
michael@0:     // |faceforward(N, I, Nref)| is |dot(NRef, I) < 0 ? N : -N|
michael@0:     "#define webgl_faceforward_emu(N, I, Nref) (((Nref) * (I) < 0.0) ? (N) : -(N))",
michael@0:     "#error no emulation for faceforward(vec2, vec2, vec2)",
michael@0:     "#error no emulation for faceforward(vec3, vec3, vec3)",
michael@0:     "#error no emulation for faceforward(vec4, vec4, vec4)",
michael@0: 
michael@0:     "#define webgl_length_emu(x) ((x) >= 0.0 ? (x) : -(x))",
michael@0:     "#error no emulation for length(vec2)",
michael@0:     "#error no emulation for length(vec3)",
michael@0:     "#error no emulation for length(vec4)",
michael@0: 
michael@0:     "#define webgl_normalize_emu(x) ((x) == 0.0 ? 0.0 : ((x) > 0.0 ? 1.0 : -1.0))",
michael@0:     "#error no emulation for normalize(vec2)",
michael@0:     "#error no emulation for normalize(vec3)",
michael@0:     "#error no emulation for normalize(vec4)",
michael@0: 
michael@0:     "#define webgl_reflect_emu(I, N) ((I) - 2.0 * (N) * (I) * (N))",
michael@0:     "#error no emulation for reflect(vec2, vec2)",
michael@0:     "#error no emulation for reflect(vec3, vec3)",
michael@0:     "#error no emulation for reflect(vec4, vec4)"
michael@0: };
michael@0: 
michael@0: const bool kFunctionEmulationVertexMask[] = {
michael@0: #if defined(__APPLE__)
michael@0:     // Work around ATI driver bugs in Mac.
michael@0:     false, // TFunctionCos1
michael@0:     false, // TFunctionCos2
michael@0:     false, // TFunctionCos3
michael@0:     false, // TFunctionCos4
michael@0:     true,  // TFunctionDistance1_1
michael@0:     false, // TFunctionDistance2_2
michael@0:     false, // TFunctionDistance3_3
michael@0:     false, // TFunctionDistance4_4
michael@0:     true,  // TFunctionDot1_1
michael@0:     false, // TFunctionDot2_2
michael@0:     false, // TFunctionDot3_3
michael@0:     false, // TFunctionDot4_4
michael@0:     true,  // TFunctionFaceForward1_1_1
michael@0:     false, // TFunctionFaceForward2_2_2
michael@0:     false, // TFunctionFaceForward3_3_3
michael@0:     false, // TFunctionFaceForward4_4_4
michael@0:     true,  // TFunctionLength1
michael@0:     false, // TFunctionLength2
michael@0:     false, // TFunctionLength3
michael@0:     false, // TFunctionLength4
michael@0:     true,  // TFunctionNormalize1
michael@0:     false, // TFunctionNormalize2
michael@0:     false, // TFunctionNormalize3
michael@0:     false, // TFunctionNormalize4
michael@0:     true,  // TFunctionReflect1_1
michael@0:     false, // TFunctionReflect2_2
michael@0:     false, // TFunctionReflect3_3
michael@0:     false, // TFunctionReflect4_4
michael@0: #else
michael@0:     // Work around D3D driver bug in Win.
michael@0:     false, // TFunctionCos1
michael@0:     false, // TFunctionCos2
michael@0:     false, // TFunctionCos3
michael@0:     false, // TFunctionCos4
michael@0:     false, // TFunctionDistance1_1
michael@0:     false, // TFunctionDistance2_2
michael@0:     false, // TFunctionDistance3_3
michael@0:     false, // TFunctionDistance4_4
michael@0:     false, // TFunctionDot1_1
michael@0:     false, // TFunctionDot2_2
michael@0:     false, // TFunctionDot3_3
michael@0:     false, // TFunctionDot4_4
michael@0:     false, // TFunctionFaceForward1_1_1
michael@0:     false, // TFunctionFaceForward2_2_2
michael@0:     false, // TFunctionFaceForward3_3_3
michael@0:     false, // TFunctionFaceForward4_4_4
michael@0:     false, // TFunctionLength1
michael@0:     false, // TFunctionLength2
michael@0:     false, // TFunctionLength3
michael@0:     false, // TFunctionLength4
michael@0:     false, // TFunctionNormalize1
michael@0:     false, // TFunctionNormalize2
michael@0:     false, // TFunctionNormalize3
michael@0:     false, // TFunctionNormalize4
michael@0:     false, // TFunctionReflect1_1
michael@0:     false, // TFunctionReflect2_2
michael@0:     false, // TFunctionReflect3_3
michael@0:     false, // TFunctionReflect4_4
michael@0: #endif
michael@0:     false  // TFunctionUnknown
michael@0: };
michael@0: 
michael@0: const bool kFunctionEmulationFragmentMask[] = {
michael@0: #if defined(__APPLE__)
michael@0:     // Work around ATI driver bugs in Mac.
michael@0:     true,  // TFunctionCos1
michael@0:     true,  // TFunctionCos2
michael@0:     true,  // TFunctionCos3
michael@0:     true,  // TFunctionCos4
michael@0:     true,  // TFunctionDistance1_1
michael@0:     false, // TFunctionDistance2_2
michael@0:     false, // TFunctionDistance3_3
michael@0:     false, // TFunctionDistance4_4
michael@0:     true,  // TFunctionDot1_1
michael@0:     false, // TFunctionDot2_2
michael@0:     false, // TFunctionDot3_3
michael@0:     false, // TFunctionDot4_4
michael@0:     true,  // TFunctionFaceForward1_1_1
michael@0:     false, // TFunctionFaceForward2_2_2
michael@0:     false, // TFunctionFaceForward3_3_3
michael@0:     false, // TFunctionFaceForward4_4_4
michael@0:     true,  // TFunctionLength1
michael@0:     false, // TFunctionLength2
michael@0:     false, // TFunctionLength3
michael@0:     false, // TFunctionLength4
michael@0:     true,  // TFunctionNormalize1
michael@0:     false, // TFunctionNormalize2
michael@0:     false, // TFunctionNormalize3
michael@0:     false, // TFunctionNormalize4
michael@0:     true,  // TFunctionReflect1_1
michael@0:     false, // TFunctionReflect2_2
michael@0:     false, // TFunctionReflect3_3
michael@0:     false, // TFunctionReflect4_4
michael@0: #else
michael@0:     // Work around D3D driver bug in Win.
michael@0:     false, // TFunctionCos1
michael@0:     false, // TFunctionCos2
michael@0:     false, // TFunctionCos3
michael@0:     false, // TFunctionCos4
michael@0:     false, // TFunctionDistance1_1
michael@0:     false, // TFunctionDistance2_2
michael@0:     false, // TFunctionDistance3_3
michael@0:     false, // TFunctionDistance4_4
michael@0:     false, // TFunctionDot1_1
michael@0:     false, // TFunctionDot2_2
michael@0:     false, // TFunctionDot3_3
michael@0:     false, // TFunctionDot4_4
michael@0:     false, // TFunctionFaceForward1_1_1
michael@0:     false, // TFunctionFaceForward2_2_2
michael@0:     false, // TFunctionFaceForward3_3_3
michael@0:     false, // TFunctionFaceForward4_4_4
michael@0:     false, // TFunctionLength1
michael@0:     false, // TFunctionLength2
michael@0:     false, // TFunctionLength3
michael@0:     false, // TFunctionLength4
michael@0:     false, // TFunctionNormalize1
michael@0:     false, // TFunctionNormalize2
michael@0:     false, // TFunctionNormalize3
michael@0:     false, // TFunctionNormalize4
michael@0:     false, // TFunctionReflect1_1
michael@0:     false, // TFunctionReflect2_2
michael@0:     false, // TFunctionReflect3_3
michael@0:     false, // TFunctionReflect4_4
michael@0: #endif
michael@0:     false  // TFunctionUnknown
michael@0: };
michael@0: 
michael@0: class BuiltInFunctionEmulationMarker : public TIntermTraverser {
michael@0: public:
michael@0:     BuiltInFunctionEmulationMarker(BuiltInFunctionEmulator& emulator)
michael@0:         : mEmulator(emulator)
michael@0:     {
michael@0:     }
michael@0: 
michael@0:     virtual bool visitUnary(Visit visit, TIntermUnary* node)
michael@0:     {
michael@0:         if (visit == PreVisit) {
michael@0:             bool needToEmulate = mEmulator.SetFunctionCalled(
michael@0:                 node->getOp(), node->getOperand()->getType());
michael@0:             if (needToEmulate)
michael@0:                 node->setUseEmulatedFunction();
michael@0:         }
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     virtual bool visitAggregate(Visit visit, TIntermAggregate* node)
michael@0:     {
michael@0:         if (visit == PreVisit) {
michael@0:             // Here we handle all the built-in functions instead of the ones we
michael@0:             // currently identified as problematic.
michael@0:             switch (node->getOp()) {
michael@0:                 case EOpLessThan:
michael@0:                 case EOpGreaterThan:
michael@0:                 case EOpLessThanEqual:
michael@0:                 case EOpGreaterThanEqual:
michael@0:                 case EOpVectorEqual:
michael@0:                 case EOpVectorNotEqual:
michael@0:                 case EOpMod:
michael@0:                 case EOpPow:
michael@0:                 case EOpAtan:
michael@0:                 case EOpMin:
michael@0:                 case EOpMax:
michael@0:                 case EOpClamp:
michael@0:                 case EOpMix:
michael@0:                 case EOpStep:
michael@0:                 case EOpSmoothStep:
michael@0:                 case EOpDistance:
michael@0:                 case EOpDot:
michael@0:                 case EOpCross:
michael@0:                 case EOpFaceForward:
michael@0:                 case EOpReflect:
michael@0:                 case EOpRefract:
michael@0:                 case EOpMul:
michael@0:                     break;
michael@0:                 default:
michael@0:                     return true;
michael@0:             };
michael@0:             const TIntermSequence& sequence = node->getSequence();
michael@0:             bool needToEmulate = false;
michael@0: 
michael@0:             if (sequence.size() == 2) {
michael@0:                 TIntermTyped* param1 = sequence[0]->getAsTyped();
michael@0:                 TIntermTyped* param2 = sequence[1]->getAsTyped();
michael@0:                 if (!param1 || !param2)
michael@0:                     return true;
michael@0:                 needToEmulate = mEmulator.SetFunctionCalled(
michael@0:                     node->getOp(), param1->getType(), param2->getType());
michael@0:             } else if (sequence.size() == 3) {
michael@0:                 TIntermTyped* param1 = sequence[0]->getAsTyped();
michael@0:                 TIntermTyped* param2 = sequence[1]->getAsTyped();
michael@0:                 TIntermTyped* param3 = sequence[2]->getAsTyped();
michael@0:                 if (!param1 || !param2 || !param3)
michael@0:                     return true;
michael@0:                 needToEmulate = mEmulator.SetFunctionCalled(
michael@0:                     node->getOp(), param1->getType(), param2->getType(), param3->getType());
michael@0:             } else {
michael@0:                 return true;
michael@0:             }
michael@0: 
michael@0:             if (needToEmulate)
michael@0:                 node->setUseEmulatedFunction();
michael@0:         }
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     BuiltInFunctionEmulator& mEmulator;
michael@0: };
michael@0: 
michael@0: }  // anonymous namepsace
michael@0: 
michael@0: BuiltInFunctionEmulator::BuiltInFunctionEmulator(ShShaderType shaderType)
michael@0: {
michael@0:     if (shaderType == SH_FRAGMENT_SHADER) {
michael@0:         mFunctionMask = kFunctionEmulationFragmentMask;
michael@0:         mFunctionSource = kFunctionEmulationFragmentSource;
michael@0:     } else {
michael@0:         mFunctionMask = kFunctionEmulationVertexMask;
michael@0:         mFunctionSource = kFunctionEmulationVertexSource;
michael@0:     }
michael@0: }
michael@0: 
michael@0: bool BuiltInFunctionEmulator::SetFunctionCalled(
michael@0:     TOperator op, const TType& param)
michael@0: {
michael@0:     TBuiltInFunction function = IdentifyFunction(op, param);
michael@0:     return SetFunctionCalled(function);
michael@0: }
michael@0: 
michael@0: bool BuiltInFunctionEmulator::SetFunctionCalled(
michael@0:     TOperator op, const TType& param1, const TType& param2)
michael@0: {
michael@0:     TBuiltInFunction function = IdentifyFunction(op, param1, param2);
michael@0:     return SetFunctionCalled(function);
michael@0: }
michael@0: 
michael@0: bool BuiltInFunctionEmulator::SetFunctionCalled(
michael@0:     TOperator op, const TType& param1, const TType& param2, const TType& param3)
michael@0: {
michael@0:     TBuiltInFunction function = IdentifyFunction(op, param1, param2, param3);
michael@0:     return SetFunctionCalled(function);
michael@0: }
michael@0: 
michael@0: bool BuiltInFunctionEmulator::SetFunctionCalled(
michael@0:     BuiltInFunctionEmulator::TBuiltInFunction function) {
michael@0:     if (function == TFunctionUnknown || mFunctionMask[function] == false)
michael@0:         return false;
michael@0:     for (size_t i = 0; i < mFunctions.size(); ++i) {
michael@0:         if (mFunctions[i] == function)
michael@0:             return true;
michael@0:     }
michael@0:     mFunctions.push_back(function);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void BuiltInFunctionEmulator::OutputEmulatedFunctionDefinition(
michael@0:     TInfoSinkBase& out, bool withPrecision) const
michael@0: {
michael@0:     if (mFunctions.size() == 0)
michael@0:         return;
michael@0:     out << "// BEGIN: Generated code for built-in function emulation\n\n";
michael@0:     if (withPrecision) {
michael@0:         out << "#if defined(GL_FRAGMENT_PRECISION_HIGH)\n"
michael@0:             << "#define webgl_emu_precision highp\n"
michael@0:             << "#else\n"
michael@0:             << "#define webgl_emu_precision mediump\n"
michael@0:             << "#endif\n\n";
michael@0:     } else {
michael@0:         out << "#define webgl_emu_precision\n\n";
michael@0:     }
michael@0:     for (size_t i = 0; i < mFunctions.size(); ++i) {
michael@0:         out << mFunctionSource[mFunctions[i]] << "\n\n";
michael@0:     }
michael@0:     out << "// END: Generated code for built-in function emulation\n\n";
michael@0: }
michael@0: 
michael@0: BuiltInFunctionEmulator::TBuiltInFunction
michael@0: BuiltInFunctionEmulator::IdentifyFunction(
michael@0:     TOperator op, const TType& param)
michael@0: {
michael@0:     if (param.getNominalSize() > 4)
michael@0:         return TFunctionUnknown;
michael@0:     unsigned int function = TFunctionUnknown;
michael@0:     switch (op) {
michael@0:         case EOpCos:
michael@0:             function = TFunctionCos1;
michael@0:             break;
michael@0:         case EOpLength:
michael@0:             function = TFunctionLength1;
michael@0:             break;
michael@0:         case EOpNormalize:
michael@0:             function = TFunctionNormalize1;
michael@0:             break;
michael@0:         default:
michael@0:             break;
michael@0:     }
michael@0:     if (function == TFunctionUnknown)
michael@0:         return TFunctionUnknown;
michael@0:     if (param.isVector())
michael@0:         function += param.getNominalSize() - 1;
michael@0:     return static_cast<TBuiltInFunction>(function);
michael@0: }
michael@0: 
michael@0: BuiltInFunctionEmulator::TBuiltInFunction
michael@0: BuiltInFunctionEmulator::IdentifyFunction(
michael@0:     TOperator op, const TType& param1, const TType& param2)
michael@0: {
michael@0:     // Right now for all the emulated functions with two parameters, the two
michael@0:     // parameters have the same type.
michael@0:     if (param1.isVector() != param2.isVector() ||
michael@0:         param1.getNominalSize() != param2.getNominalSize() ||
michael@0:         param1.getNominalSize() > 4)
michael@0:         return TFunctionUnknown;
michael@0: 
michael@0:     unsigned int function = TFunctionUnknown;
michael@0:     switch (op) {
michael@0:         case EOpDistance:
michael@0:             function = TFunctionDistance1_1;
michael@0:             break;
michael@0:         case EOpDot:
michael@0:             function = TFunctionDot1_1;
michael@0:             break;
michael@0:         case EOpReflect:
michael@0:             function = TFunctionReflect1_1;
michael@0:             break;
michael@0:         default:
michael@0:             break;
michael@0:     }
michael@0:     if (function == TFunctionUnknown)
michael@0:         return TFunctionUnknown;
michael@0:     if (param1.isVector())
michael@0:         function += param1.getNominalSize() - 1;
michael@0:     return static_cast<TBuiltInFunction>(function);
michael@0: }
michael@0: 
michael@0: BuiltInFunctionEmulator::TBuiltInFunction
michael@0: BuiltInFunctionEmulator::IdentifyFunction(
michael@0:     TOperator op, const TType& param1, const TType& param2, const TType& param3)
michael@0: {
michael@0:     // Check that all params have the same type, length,
michael@0:     // and that they're not too large.
michael@0:     if (param1.isVector() != param2.isVector() ||
michael@0:         param2.isVector() != param3.isVector() ||
michael@0:         param1.getNominalSize() != param2.getNominalSize() ||
michael@0:         param2.getNominalSize() != param3.getNominalSize() ||
michael@0:         param1.getNominalSize() > 4)
michael@0:         return TFunctionUnknown;
michael@0: 
michael@0:     unsigned int function = TFunctionUnknown;
michael@0:     switch (op) {
michael@0:         case EOpFaceForward:
michael@0:             function = TFunctionFaceForward1_1_1;
michael@0:             break;
michael@0:         default:
michael@0:             break;
michael@0:     }
michael@0:     if (function == TFunctionUnknown)
michael@0:         return TFunctionUnknown;
michael@0:     if (param1.isVector())
michael@0:         function += param1.getNominalSize() - 1;
michael@0:     return static_cast<TBuiltInFunction>(function);
michael@0: }
michael@0: 
michael@0: void BuiltInFunctionEmulator::MarkBuiltInFunctionsForEmulation(
michael@0:     TIntermNode* root)
michael@0: {
michael@0:     ASSERT(root);
michael@0: 
michael@0:     BuiltInFunctionEmulationMarker marker(*this);
michael@0:     root->traverse(&marker);
michael@0: }
michael@0: 
michael@0: void BuiltInFunctionEmulator::Cleanup()
michael@0: {
michael@0:     mFunctions.clear();
michael@0: }
michael@0: 
michael@0: //static
michael@0: TString BuiltInFunctionEmulator::GetEmulatedFunctionName(
michael@0:     const TString& name)
michael@0: {
michael@0:     ASSERT(name[name.length() - 1] == '(');
michael@0:     return "webgl_" + name.substr(0, name.length() - 1) + "_emu(";
michael@0: }
michael@0: