Hash :
e7557744
Author :
Date :
2017-06-01T13:09:57
WebGL compatibility: remove UB for draw buffers in the GL backend. WebGL adds two rules: - Fragment outputs declared but not written to should default to black. - FBO attachments for outputs not declared in the shader should not be written to (it is UB in OpenGL ES). Fix the first one by using the SH_INIT_OUTPUT_VARIABLES compiler options, and the second one by messing with glDrawBuffers so that the enabled draw buffers are always a subset of the ones declared by the shader. BUG=angleproject:2048 Change-Id: I1d851c190959c1acfc3e41d837e6990aec1d4086 Reviewed-on: https://chromium-review.googlesource.com/521682 Commit-Queue: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>
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//
// Copyright 2015 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.
//
// ShaderGL.cpp: Implements the class methods for ShaderGL.
#include "libANGLE/renderer/gl/ShaderGL.h"
#include "common/debug.h"
#include "libANGLE/Compiler.h"
#include "libANGLE/renderer/gl/FunctionsGL.h"
#include "libANGLE/renderer/gl/RendererGL.h"
#include "libANGLE/renderer/gl/WorkaroundsGL.h"
#include <iostream>
namespace rx
{
ShaderGL::ShaderGL(const gl::ShaderState &data,
const FunctionsGL *functions,
const WorkaroundsGL &workarounds,
bool isWebGL)
: ShaderImpl(data),
mFunctions(functions),
mWorkarounds(workarounds),
mShaderID(0),
mIsWebGL(isWebGL)
{
ASSERT(mFunctions);
}
ShaderGL::~ShaderGL()
{
if (mShaderID != 0)
{
mFunctions->deleteShader(mShaderID);
mShaderID = 0;
}
}
ShCompileOptions ShaderGL::prepareSourceAndReturnOptions(std::stringstream *sourceStream,
std::string * /*sourcePath*/)
{
// Reset the previous state
if (mShaderID != 0)
{
mFunctions->deleteShader(mShaderID);
mShaderID = 0;
}
*sourceStream << mData.getSource();
ShCompileOptions options = SH_INIT_GL_POSITION;
if (mIsWebGL)
{
options |= SH_INIT_OUTPUT_VARIABLES;
}
if (mWorkarounds.doWhileGLSLCausesGPUHang)
{
options |= SH_REWRITE_DO_WHILE_LOOPS;
}
if (mWorkarounds.emulateAbsIntFunction)
{
options |= SH_EMULATE_ABS_INT_FUNCTION;
}
if (mWorkarounds.addAndTrueToLoopCondition)
{
options |= SH_ADD_AND_TRUE_TO_LOOP_CONDITION;
}
if (mWorkarounds.emulateIsnanFloat)
{
options |= SH_EMULATE_ISNAN_FLOAT_FUNCTION;
}
if (mWorkarounds.emulateAtan2Float)
{
options |= SH_EMULATE_ATAN2_FLOAT_FUNCTION;
}
if (mWorkarounds.useUnusedBlocksWithStandardOrSharedLayout)
{
options |= SH_USE_UNUSED_STANDARD_SHARED_BLOCKS;
}
if (mWorkarounds.dontRemoveInvariantForFragmentInput)
{
options |= SH_DONT_REMOVE_INVARIANT_FOR_FRAGMENT_INPUT;
}
if (mWorkarounds.removeInvariantAndCentroidForESSL3)
{
options |= SH_REMOVE_INVARIANT_AND_CENTROID_FOR_ESSL3;
}
if (mWorkarounds.rewriteFloatUnaryMinusOperator)
{
options |= SH_REWRITE_FLOAT_UNARY_MINUS_OPERATOR;
}
if (!mWorkarounds.dontInitializeUninitializedLocals)
{
options |= SH_INITIALIZE_UNINITIALIZED_LOCALS;
}
return options;
}
bool ShaderGL::postTranslateCompile(gl::Compiler *compiler, std::string *infoLog)
{
// Translate the ESSL into GLSL
const char *translatedSourceCString = mData.getTranslatedSource().c_str();
// Generate a shader object and set the source
mShaderID = mFunctions->createShader(mData.getShaderType());
mFunctions->shaderSource(mShaderID, 1, &translatedSourceCString, nullptr);
mFunctions->compileShader(mShaderID);
// Check for compile errors from the native driver
GLint compileStatus = GL_FALSE;
mFunctions->getShaderiv(mShaderID, GL_COMPILE_STATUS, &compileStatus);
if (compileStatus == GL_FALSE)
{
// Compilation failed, put the error into the info log
GLint infoLogLength = 0;
mFunctions->getShaderiv(mShaderID, GL_INFO_LOG_LENGTH, &infoLogLength);
// Info log length includes the null terminator, so 1 means that the info log is an empty
// string.
if (infoLogLength > 1)
{
std::vector<char> buf(infoLogLength);
mFunctions->getShaderInfoLog(mShaderID, infoLogLength, nullptr, &buf[0]);
mFunctions->deleteShader(mShaderID);
mShaderID = 0;
*infoLog = &buf[0];
WARN() << std::endl << *infoLog;
}
else
{
WARN() << std::endl << "Shader compilation failed with no info log.";
}
return false;
}
return true;
}
std::string ShaderGL::getDebugInfo() const
{
return mData.getTranslatedSource();
}
GLuint ShaderGL::getShaderID() const
{
return mShaderID;
}
}