1 //
2 // Copyright 2017 The ANGLE Project Authors. All rights reserved.
3 // Use of this source code is governed by a BSD-style license that can be
4 // found in the LICENSE file.
5 //
6 // ClampPointSize.cpp: Limit the value that is written to gl_PointSize.
7 //
8
9 #include "compiler/translator/tree_ops/ClampPointSize.h"
10
11 #include "compiler/translator/SymbolTable.h"
12 #include "compiler/translator/tree_util/BuiltIn.h"
13 #include "compiler/translator/tree_util/FindSymbolNode.h"
14 #include "compiler/translator/tree_util/IntermNode_util.h"
15 #include "compiler/translator/tree_util/RunAtTheEndOfShader.h"
16
17 namespace sh
18 {
19
ClampPointSize(TCompiler * compiler,TIntermBlock * root,float maxPointSize,TSymbolTable * symbolTable)20 bool ClampPointSize(TCompiler *compiler,
21 TIntermBlock *root,
22 float maxPointSize,
23 TSymbolTable *symbolTable)
24 {
25 // Only clamp gl_PointSize if it's used in the shader.
26 if (!FindSymbolNode(root, ImmutableString("gl_PointSize")))
27 {
28 return true;
29 }
30
31 TIntermSymbol *pointSizeNode = new TIntermSymbol(BuiltInVariable::gl_PointSize());
32
33 TConstantUnion *maxPointSizeConstant = new TConstantUnion();
34 maxPointSizeConstant->setFConst(maxPointSize);
35 TIntermConstantUnion *maxPointSizeNode =
36 new TIntermConstantUnion(maxPointSizeConstant, TType(EbtFloat, EbpHigh, EvqConst));
37
38 // min(gl_PointSize, maxPointSize)
39 TIntermSequence *minArguments = new TIntermSequence();
40 minArguments->push_back(pointSizeNode->deepCopy());
41 minArguments->push_back(maxPointSizeNode);
42 TIntermTyped *clampedPointSize =
43 CreateBuiltInFunctionCallNode("min", minArguments, *symbolTable, 100);
44
45 // gl_PointSize = min(gl_PointSize, maxPointSize)
46 TIntermBinary *assignPointSize = new TIntermBinary(EOpAssign, pointSizeNode, clampedPointSize);
47
48 return RunAtTheEndOfShader(compiler, root, assignPointSize, symbolTable);
49 }
50
51 } // namespace sh
52