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//
// Copyright (c) 2002-2013 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/translator/TranslatorGLSL.h"
#include "angle_gl.h"
#include "compiler/translator/BuiltInFunctionEmulatorGLSL.h"
#include "compiler/translator/EmulatePrecision.h"
#include "compiler/translator/OutputGLSL.h"
#include "compiler/translator/VersionGLSL.h"
namespace
{
// To search for what output variables are used in a fragment shader.
// We handle gl_FragColor and gl_FragData at the moment.
class TFragmentOutSearcher : public TIntermTraverser
{
public:
TFragmentOutSearcher()
: mUsesGlFragColor(false),
mUsesGlFragData(false)
{
}
bool usesGlFragColor() const
{
return mUsesGlFragColor;
}
bool usesGlFragData() const
{
return mUsesGlFragData;
}
protected:
virtual void visitSymbol(TIntermSymbol *node) override
{
if (node->getSymbol() == "gl_FragColor")
{
mUsesGlFragColor = true;
}
else if (node->getSymbol() == "gl_FragData")
{
mUsesGlFragData = true;
}
}
private:
bool mUsesGlFragColor;
bool mUsesGlFragData;
};
} // namespace anonymous
TranslatorGLSL::TranslatorGLSL(sh::GLenum type,
ShShaderSpec spec,
ShShaderOutput output)
: TCompiler(type, spec, output) {
}
void TranslatorGLSL::initBuiltInFunctionEmulator(BuiltInFunctionEmulator *emu, int compileOptions)
{
if (compileOptions & SH_EMULATE_BUILT_IN_FUNCTIONS)
InitBuiltInFunctionEmulatorForGLSL(emu, getShaderType());
}
void TranslatorGLSL::translate(TIntermNode *root, int) {
TInfoSinkBase& sink = getInfoSink().obj;
// Write GLSL version.
writeVersion(root);
writePragma();
// Write extension behaviour as needed
writeExtensionBehavior();
bool precisionEmulation = getResources().WEBGL_debug_shader_precision && getPragma().debugShaderPrecision;
if (precisionEmulation)
{
EmulatePrecision emulatePrecision;
root->traverse(&emulatePrecision);
emulatePrecision.updateTree();
emulatePrecision.writeEmulationHelpers(sink, getOutputType());
}
// Write emulated built-in functions if needed.
if (!getBuiltInFunctionEmulator().IsOutputEmpty())
{
sink << "// BEGIN: Generated code for built-in function emulation\n\n";
sink << "#define webgl_emu_precision\n\n";
getBuiltInFunctionEmulator().OutputEmulatedFunctions(sink);
sink << "// END: Generated code for built-in function emulation\n\n";
}
// Write array bounds clamping emulation if needed.
getArrayBoundsClamper().OutputClampingFunctionDefinition(sink);
// Declare gl_FragColor and glFragData as webgl_FragColor and webgl_FragData
// if it's core profile shaders and they are used.
if (getShaderType() == GL_FRAGMENT_SHADER &&
getOutputType() == SH_GLSL_CORE_OUTPUT)
{
TFragmentOutSearcher searcher;
root->traverse(&searcher);
ASSERT(!(searcher.usesGlFragData() && searcher.usesGlFragColor()));
if (searcher.usesGlFragColor())
{
sink << "out vec4 webgl_FragColor;\n";
}
if (searcher.usesGlFragData())
{
sink << "out vec4 webgl_FragData[gl_MaxDrawBuffers];\n";
}
}
// Write translated shader.
TOutputGLSL outputGLSL(sink,
getArrayIndexClampingStrategy(),
getHashFunction(),
getNameMap(),
getSymbolTable(),
getShaderVersion(),
getOutputType());
root->traverse(&outputGLSL);
}
void TranslatorGLSL::writeVersion(TIntermNode *root)
{
TVersionGLSL versionGLSL(getShaderType(), getPragma(), getOutputType());
root->traverse(&versionGLSL);
int version = versionGLSL.getVersion();
// We need to write version directive only if it is greater than 110.
// If there is no version directive in the shader, 110 is implied.
if (version > 110)
{
TInfoSinkBase& sink = getInfoSink().obj;
sink << "#version " << version << "\n";
}
}
void TranslatorGLSL::writeExtensionBehavior() {
TInfoSinkBase& sink = getInfoSink().obj;
const TExtensionBehavior& extBehavior = getExtensionBehavior();
for (TExtensionBehavior::const_iterator iter = extBehavior.begin();
iter != extBehavior.end(); ++iter) {
if (iter->second == EBhUndefined)
continue;
// For GLSL output, we don't need to emit most extensions explicitly,
// but some we need to translate.
if (iter->first == "GL_EXT_shader_texture_lod") {
sink << "#extension GL_ARB_shader_texture_lod : "
<< getBehaviorString(iter->second) << "\n";
}
}
}
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