1 files changed, 52 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/compiler/translator/tree_ops/ClampPointSize.cpp b/gfx/angle/checkout/src/compiler/translator/tree_ops/ClampPointSize.cpp
new file mode 100644
index 0000000000..db006989e9
--- /dev/null
+++ b/gfx/angle/checkout/src/compiler/translator/tree_ops/ClampPointSize.cpp
@@ -0,0 +1,52 @@
+//
+// 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