BuiltInFunctionEmulator.cpp

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Author : zmo@google.com
Date : 2012-04-12 23:09:59
Hash : 57442b11
Message : Update emulated functions. It turns out there are bugs in our tests, so kbr fixed them a while ago. Now we had another look at the tests, and it turned out some functions we don't have emulate, and some functions we need to also emulate in fragment shaders. BUG= TEST= R=kbr Review URL: https://codereview.appspot.com/6011056 git-svn-id: https://angleproject.googlecode.com/svn/trunk@1034 736b8ea6-26fd-11df-bfd4-992fa37f6226
src/compiler/BuiltInFunctionEmulator.cpp
//
// Copyright (c) 2002-2011 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

#include "compiler/BuiltInFunctionEmulator.h"

#include "compiler/SymbolTable.h"

namespace {

// we use macros here instead of function definitions to work around more GLSL
// compiler bugs, in particular on NVIDIA hardware on Mac OSX. Macros are
// problematic because if the argument has side-effects they will be repeatedly
// evaluated. This is unlikely to show up in real shaders, but is something to
// consider.
const char* kFunctionEmulationVertexSource[] = {
    "#error no emulation for cos(float)",
    "#error no emulation for cos(vec2)",
    "#error no emulation for cos(vec3)",
    "#error no emulation for cos(vec4)",

    "#define webgl_distance_emu(x, y) ((x) >= (y) ? (x) - (y) : (y) - (x))",
    "#error no emulation for distance(vec2, vec2)",
    "#error no emulation for distance(vec3, vec3)",
    "#error no emulation for distance(vec4, vec4)",

    "#define webgl_dot_emu(x, y) ((x) * (y))",
    "#error no emulation for dot(vec2, vec2)",
    "#error no emulation for dot(vec3, vec3)",
    "#error no emulation for dot(vec4, vec4)",

    "#define webgl_length_emu(x) ((x) >= 0.0 ? (x) : -(x))",
    "#error no emulation for length(vec2)",
    "#error no emulation for length(vec3)",
    "#error no emulation for length(vec4)",

    "#define webgl_normalize_emu(x) ((x) == 0.0 ? 0.0 : ((x) > 0.0 ? 1.0 : -1.0))",
    "#error no emulation for normalize(vec2)",
    "#error no emulation for normalize(vec3)",
    "#error no emulation for normalize(vec4)",

    "#define webgl_reflect_emu(I, N) ((I) - 2.0 * (N) * (I) * (N))",
    "#error no emulation for reflect(vec2, vec2)",
    "#error no emulation for reflect(vec3, vec3)",
    "#error no emulation for reflect(vec4, vec4)"
};

const char* kFunctionEmulationFragmentSource[] = {
    "webgl_emu_precision float webgl_cos_emu(webgl_emu_precision float a) { return cos(a); }",
    "webgl_emu_precision vec2 webgl_cos_emu(webgl_emu_precision vec2 a) { return cos(a); }",
    "webgl_emu_precision vec3 webgl_cos_emu(webgl_emu_precision vec3 a) { return cos(a); }",
    "webgl_emu_precision vec4 webgl_cos_emu(webgl_emu_precision vec4 a) { return cos(a); }",

    "#define webgl_distance_emu(x, y) ((x) >= (y) ? (x) - (y) : (y) - (x))",
    "#error no emulation for distance(vec2, vec2)",
    "#error no emulation for distance(vec3, vec3)",
    "#error no emulation for distance(vec4, vec4)",

    "#define webgl_dot_emu(x, y) ((x) * (y))",
    "#error no emulation for dot(vec2, vec2)",
    "#error no emulation for dot(vec3, vec3)",
    "#error no emulation for dot(vec4, vec4)",

    "#define webgl_length_emu(x) ((x) >= 0.0 ? (x) : -(x))",
    "#error no emulation for length(vec2)",
    "#error no emulation for length(vec3)",
    "#error no emulation for length(vec4)",

    "#define webgl_normalize_emu(x) ((x) == 0.0 ? 0.0 : ((x) > 0.0 ? 1.0 : -1.0))",
    "#error no emulation for normalize(vec2)",
    "#error no emulation for normalize(vec3)",
    "#error no emulation for normalize(vec4)",

    "#define webgl_reflect_emu(I, N) ((I) - 2.0 * (N) * (I) * (N))",
    "#error no emulation for reflect(vec2, vec2)",
    "#error no emulation for reflect(vec3, vec3)",
    "#error no emulation for reflect(vec4, vec4)"
};

const bool kFunctionEmulationVertexMask[] = {
#if defined(__APPLE__)
    // Work around ATI driver bugs in Mac.
    false, // TFunctionCos1
    false, // TFunctionCos2
    false, // TFunctionCos3
    false, // TFunctionCos4
    true,  // TFunctionDistance1_1
    false, // TFunctionDistance2_2
    false, // TFunctionDistance3_3
    false, // TFunctionDistance4_4
    true,  // TFunctionDot1_1
    false, // TFunctionDot2_2
    false, // TFunctionDot3_3
    false, // TFunctionDot4_4
    true,  // TFunctionLength1
    false, // TFunctionLength2
    false, // TFunctionLength3
    false, // TFunctionLength4
    true,  // TFunctionNormalize1
    false, // TFunctionNormalize2
    false, // TFunctionNormalize3
    false, // TFunctionNormalize4
    true,  // TFunctionReflect1_1
    false, // TFunctionReflect2_2
    false, // TFunctionReflect3_3
    false, // TFunctionReflect4_4
#else
    // Work around D3D driver bug in Win.
    false, // TFunctionCos1
    false, // TFunctionCos2
    false, // TFunctionCos3
    false, // TFunctionCos4
    false, // TFunctionDistance1_1
    false, // TFunctionDistance2_2
    false, // TFunctionDistance3_3
    false, // TFunctionDistance4_4
    false, // TFunctionDot1_1
    false, // TFunctionDot2_2
    false, // TFunctionDot3_3
    false, // TFunctionDot4_4
    false, // TFunctionLength1
    false, // TFunctionLength2
    false, // TFunctionLength3
    false, // TFunctionLength4
    false, // TFunctionNormalize1
    false, // TFunctionNormalize2
    false, // TFunctionNormalize3
    false, // TFunctionNormalize4
    false, // TFunctionReflect1_1
    false, // TFunctionReflect2_2
    false, // TFunctionReflect3_3
    false, // TFunctionReflect4_4
#endif
    false  // TFunctionUnknown
};

const bool kFunctionEmulationFragmentMask[] = {
#if defined(__APPLE__)
    // Work around ATI driver bugs in Mac.
    true,  // TFunctionCos1
    true,  // TFunctionCos2
    true,  // TFunctionCos3
    true,  // TFunctionCos4
    true,  // TFunctionDistance1_1
    false, // TFunctionDistance2_2
    false, // TFunctionDistance3_3
    false, // TFunctionDistance4_4
    true,  // TFunctionDot1_1
    false, // TFunctionDot2_2
    false, // TFunctionDot3_3
    false, // TFunctionDot4_4
    true,  // TFunctionLength1
    false, // TFunctionLength2
    false, // TFunctionLength3
    false, // TFunctionLength4
    true,  // TFunctionNormalize1
    false, // TFunctionNormalize2
    false, // TFunctionNormalize3
    false, // TFunctionNormalize4
    true,  // TFunctionReflect1_1
    false, // TFunctionReflect2_2
    false, // TFunctionReflect3_3
    false, // TFunctionReflect4_4
#else
    // Work around D3D driver bug in Win.
    false, // TFunctionCos1
    false, // TFunctionCos2
    false, // TFunctionCos3
    false, // TFunctionCos4
    false, // TFunctionDistance1_1
    false, // TFunctionDistance2_2
    false, // TFunctionDistance3_3
    false, // TFunctionDistance4_4
    false, // TFunctionDot1_1
    false, // TFunctionDot2_2
    false, // TFunctionDot3_3
    false, // TFunctionDot4_4
    false, // TFunctionLength1
    false, // TFunctionLength2
    false, // TFunctionLength3
    false, // TFunctionLength4
    false, // TFunctionNormalize1
    false, // TFunctionNormalize2
    false, // TFunctionNormalize3
    false, // TFunctionNormalize4
    false, // TFunctionReflect1_1
    false, // TFunctionReflect2_2
    false, // TFunctionReflect3_3
    false, // TFunctionReflect4_4
#endif
    false  // TFunctionUnknown
};

class BuiltInFunctionEmulationMarker : public TIntermTraverser {
public:
    BuiltInFunctionEmulationMarker(BuiltInFunctionEmulator& emulator)
        : mEmulator(emulator)
    {
    }

    virtual bool visitUnary(Visit visit, TIntermUnary* node)
    {
        if (visit == PreVisit) {
            bool needToEmulate = mEmulator.SetFunctionCalled(
                node->getOp(), node->getOperand()->getType());
            if (needToEmulate)
                node->setUseEmulatedFunction();
        }
        return true;
    }

    virtual bool visitAggregate(Visit visit, TIntermAggregate* node)
    {
        if (visit == PreVisit) {
            // Here we handle all the built-in functions instead of the ones we
            // currently identified as problematic.
            switch (node->getOp()) {
                case EOpLessThan:
                case EOpGreaterThan:
                case EOpLessThanEqual:
                case EOpGreaterThanEqual:
                case EOpVectorEqual:
                case EOpVectorNotEqual:
                case EOpMod:
                case EOpPow:
                case EOpAtan:
                case EOpMin:
                case EOpMax:
                case EOpClamp:
                case EOpMix:
                case EOpStep:
                case EOpSmoothStep:
                case EOpDistance:
                case EOpDot:
                case EOpCross:
                case EOpFaceForward:
                case EOpReflect:
                case EOpRefract:
                case EOpMul:
                    break;
                default:
                    return true;
            };
            const TIntermSequence& sequence = node->getSequence();
            // Right now we only handle built-in functions with two parameters.
            if (sequence.size() != 2)
                return true;
            TIntermTyped* param1 = sequence[0]->getAsTyped();
            TIntermTyped* param2 = sequence[1]->getAsTyped();
            if (!param1 || !param2)
                return true;
            bool needToEmulate = mEmulator.SetFunctionCalled(
                node->getOp(), param1->getType(), param2->getType());
            if (needToEmulate)
                node->setUseEmulatedFunction();
        }
        return true;
    }

private:
    BuiltInFunctionEmulator& mEmulator;
};

}  // anonymous namepsace

BuiltInFunctionEmulator::BuiltInFunctionEmulator(ShShaderType shaderType)
{
    if (shaderType == SH_FRAGMENT_SHADER) {
        mFunctionMask = kFunctionEmulationFragmentMask;
        mFunctionSource = kFunctionEmulationFragmentSource;
    } else {
        mFunctionMask = kFunctionEmulationVertexMask;
        mFunctionSource = kFunctionEmulationVertexSource;
    }
}

bool BuiltInFunctionEmulator::SetFunctionCalled(
    TOperator op, const TType& param)
{
    TBuiltInFunction function = IdentifyFunction(op, param);
    return SetFunctionCalled(function);
}

bool BuiltInFunctionEmulator::SetFunctionCalled(
    TOperator op, const TType& param1, const TType& param2)
{
    TBuiltInFunction function = IdentifyFunction(op, param1, param2);
    return SetFunctionCalled(function);
}

bool BuiltInFunctionEmulator::SetFunctionCalled(
    BuiltInFunctionEmulator::TBuiltInFunction function) {
    if (function == TFunctionUnknown || mFunctionMask[function] == false)
        return false;
    for (size_t i = 0; i < mFunctions.size(); ++i) {
        if (mFunctions[i] == function)
            return true;
    }
    mFunctions.push_back(function);
    return true;
}

void BuiltInFunctionEmulator::OutputEmulatedFunctionDefinition(
    TInfoSinkBase& out, bool withPrecision) const
{
    if (mFunctions.size() == 0)
        return;
    out << "// BEGIN: Generated code for built-in function emulation\n\n";
    if (withPrecision) {
        out << "#if defined(GL_FRAGMENT_PRECISION_HIGH)\n"
            << "#define webgl_emu_precision highp\n"
            << "#else\n"
            << "#define webgl_emu_precision mediump\n"
            << "#endif\n\n";
    } else {
        out << "#define webgl_emu_precision\n\n";
    }
    for (size_t i = 0; i < mFunctions.size(); ++i) {
        out << mFunctionSource[mFunctions[i]] << "\n\n";
    }
    out << "// END: Generated code for built-in function emulation\n\n";
}

BuiltInFunctionEmulator::TBuiltInFunction
BuiltInFunctionEmulator::IdentifyFunction(
    TOperator op, const TType& param)
{
    if (param.getNominalSize() > 4)
        return TFunctionUnknown;
    unsigned int function = TFunctionUnknown;
    switch (op) {
        case EOpCos:
            function = TFunctionCos1;
            break;
        case EOpLength:
            function = TFunctionLength1;
            break;
        case EOpNormalize:
            function = TFunctionNormalize1;
            break;
        default:
            break;
    }
    if (function == TFunctionUnknown)
        return TFunctionUnknown;
    if (param.isVector())
        function += param.getNominalSize() - 1;
    return static_cast<TBuiltInFunction>(function);
}

BuiltInFunctionEmulator::TBuiltInFunction
BuiltInFunctionEmulator::IdentifyFunction(
    TOperator op, const TType& param1, const TType& param2)
{
    // Right now for all the emulated functions with two parameters, the two
    // parameters have the same type.
    if (param1.isVector() != param2.isVector() ||
        param1.getNominalSize() != param2.getNominalSize() ||
        param1.getNominalSize() > 4)
        return TFunctionUnknown;

    unsigned int function = TFunctionUnknown;
    switch (op) {
        case EOpDistance:
            function = TFunctionDistance1_1;
            break;
        case EOpDot:
            function = TFunctionDot1_1;
            break;
        case EOpReflect:
            function = TFunctionReflect1_1;
            break;
        default:
            break;
    }
    if (function == TFunctionUnknown)
        return TFunctionUnknown;
    if (param1.isVector())
        function += param1.getNominalSize() - 1;
    return static_cast<TBuiltInFunction>(function);
}

void BuiltInFunctionEmulator::MarkBuiltInFunctionsForEmulation(
    TIntermNode* root)
{
    ASSERT(root);

    BuiltInFunctionEmulationMarker marker(*this);
    root->traverse(&marker);
}

void BuiltInFunctionEmulator::Cleanup()
{
    mFunctions.clear();
}

//static
TString BuiltInFunctionEmulator::GetEmulatedFunctionName(
    const TString& name)
{
    ASSERT(name[name.length() - 1] == '(');
    return "webgl_" + name.substr(0, name.length() - 1) + "_emu(";
}
kc3-lang/angle/src/compiler/BuiltInFunctionEmulator.cpp

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kc3-lang/angle /src/compiler/BuiltInFunctionEmulator.cpp
