ClampPointSize.cpp

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//

// Copyright 2017 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.

//

// ClampPointSize.cpp: Limit the value that is written to gl_PointSize.

//

#include "compiler/translator/tree_ops/ClampPointSize.h"

#include "compiler/translator/SymbolTable.h"

#include "compiler/translator/tree_util/BuiltIn.h"

#include "compiler/translator/tree_util/FindSymbolNode.h"

#include "compiler/translator/tree_util/IntermNode_util.h"

#include "compiler/translator/tree_util/RunAtTheEndOfShader.h"

namespace sh

bool ClampPointSize(TCompiler *compiler,

                    TIntermBlock *root,

                    float maxPointSize,

                    TSymbolTable *symbolTable)

    // Only clamp gl_PointSize if it's used in the shader.

    const TIntermSymbol *glPointSize = FindSymbolNode(root, ImmutableString("gl_PointSize"));

    if (glPointSize == nullptr)

        return true;

    TIntermTyped *pointSizeNode = glPointSize->deepCopy();

    TConstantUnion *maxPointSizeConstant = new TConstantUnion();

    maxPointSizeConstant->setFConst(maxPointSize);

    TIntermConstantUnion *maxPointSizeNode =

        new TIntermConstantUnion(maxPointSizeConstant, TType(EbtFloat, EbpHigh, EvqConst));

    // min(gl_PointSize, maxPointSize)

    TIntermSequence minArguments;

    minArguments.push_back(pointSizeNode->deepCopy());

    minArguments.push_back(maxPointSizeNode);

    TIntermTyped *clampedPointSize =

        CreateBuiltInFunctionCallNode("min", &minArguments, *symbolTable, 100);

    // gl_PointSize = min(gl_PointSize, maxPointSize)

    TIntermBinary *assignPointSize = new TIntermBinary(EOpAssign, pointSizeNode, clampedPointSize);

    return RunAtTheEndOfShader(compiler, root, assignPointSize, symbolTable);

}  // namespace sh