Source code

Revision control

Copy as Markdown

Other Tools

//
// Copyright 2016 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.
//
// Implementation of texelFetchOffset translation issue workaround.
// See header for more info.
#include "compiler/translator/tree_ops/RewriteTexelFetchOffset.h"
#include "common/angleutils.h"
#include "compiler/translator/SymbolTable.h"
#include "compiler/translator/tree_util/IntermNode_util.h"
#include "compiler/translator/tree_util/IntermTraverse.h"
namespace sh
{
namespace
{
class Traverser : public TIntermTraverser
{
public:
[[nodiscard]] static bool Apply(TCompiler *compiler,
TIntermNode *root,
const TSymbolTable &symbolTable,
int shaderVersion);
private:
Traverser(const TSymbolTable &symbolTable, int shaderVersion);
bool visitAggregate(Visit visit, TIntermAggregate *node) override;
void nextIteration();
const TSymbolTable *symbolTable;
const int shaderVersion;
bool mFound = false;
};
Traverser::Traverser(const TSymbolTable &symbolTable, int shaderVersion)
: TIntermTraverser(true, false, false), symbolTable(&symbolTable), shaderVersion(shaderVersion)
{}
// static
bool Traverser::Apply(TCompiler *compiler,
TIntermNode *root,
const TSymbolTable &symbolTable,
int shaderVersion)
{
Traverser traverser(symbolTable, shaderVersion);
do
{
traverser.nextIteration();
root->traverse(&traverser);
if (traverser.mFound)
{
if (!traverser.updateTree(compiler, root))
{
return false;
}
}
} while (traverser.mFound);
return true;
}
void Traverser::nextIteration()
{
mFound = false;
}
bool Traverser::visitAggregate(Visit visit, TIntermAggregate *node)
{
if (mFound)
{
return false;
}
// Decide if the node represents the call of texelFetchOffset.
if (!BuiltInGroup::IsBuiltIn(node->getOp()))
{
return true;
}
ASSERT(node->getFunction()->symbolType() == SymbolType::BuiltIn);
if (node->getFunction()->name() != "texelFetchOffset")
{
return true;
}
// Potential problem case detected, apply workaround.
const TIntermSequence *sequence = node->getSequence();
ASSERT(sequence->size() == 4u);
// Decide if the sampler is a 2DArray sampler. In that case position is ivec3 and offset is
// ivec2.
bool is2DArray = sequence->at(1)->getAsTyped()->getNominalSize() == 3 &&
sequence->at(3)->getAsTyped()->getNominalSize() == 2;
// Create new node that represents the call of function texelFetch.
// Its argument list will be: texelFetch(sampler, Position+offset, lod).
TIntermSequence texelFetchArguments;
// sampler
texelFetchArguments.push_back(sequence->at(0));
// Position
TIntermTyped *texCoordNode = sequence->at(1)->getAsTyped();
ASSERT(texCoordNode);
// offset
TIntermTyped *offsetNode = nullptr;
ASSERT(sequence->at(3)->getAsTyped());
if (is2DArray)
{
// For 2DArray samplers, Position is ivec3 and offset is ivec2;
// So offset must be converted into an ivec3 before being added to Position.
TIntermSequence constructOffsetIvecArguments;
constructOffsetIvecArguments.push_back(sequence->at(3)->getAsTyped());
TIntermTyped *zeroNode = CreateZeroNode(TType(EbtInt));
constructOffsetIvecArguments.push_back(zeroNode);
offsetNode = TIntermAggregate::CreateConstructor(texCoordNode->getType(),
&constructOffsetIvecArguments);
offsetNode->setLine(texCoordNode->getLine());
}
else
{
offsetNode = sequence->at(3)->getAsTyped();
}
// Position+offset
TIntermBinary *add = new TIntermBinary(EOpAdd, texCoordNode, offsetNode);
add->setLine(texCoordNode->getLine());
texelFetchArguments.push_back(add);
// lod
texelFetchArguments.push_back(sequence->at(2));
ASSERT(texelFetchArguments.size() == 3u);
TIntermTyped *texelFetchNode = CreateBuiltInFunctionCallNode("texelFetch", &texelFetchArguments,
*symbolTable, shaderVersion);
texelFetchNode->setLine(node->getLine());
// Replace the old node by this new node.
queueReplacement(texelFetchNode, OriginalNode::IS_DROPPED);
mFound = true;
return false;
}
} // anonymous namespace
bool RewriteTexelFetchOffset(TCompiler *compiler,
TIntermNode *root,
const TSymbolTable &symbolTable,
int shaderVersion)
{
// texelFetchOffset is only valid in GLSL 3.0 and later.
if (shaderVersion < 300)
return true;
return Traverser::Apply(compiler, root, symbolTable, shaderVersion);
}
} // namespace sh