1 files changed, 129 insertions, 0 deletions
diff --git a/src/3rdparty/angle/src/compiler/translator/EmulateGLFragColorBroadcast.cpp b/src/3rdparty/angle/src/compiler/translator/EmulateGLFragColorBroadcast.cpp
new file mode 100644
index 0000000000..189ea341eb
--- /dev/null
+++ b/src/3rdparty/angle/src/compiler/translator/EmulateGLFragColorBroadcast.cpp
@@ -0,0 +1,129 @@
+//
+// Copyright (c) 2002-2016 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.
+//
+// gl_FragColor needs to broadcast to all color buffers in ES2 if
+// GL_EXT_draw_buffers is explicitly enabled in a fragment shader.
+//
+// We emulate this by replacing all gl_FragColor with gl_FragData[0], and in the end
+// of main() function, assigning gl_FragData[1], ..., gl_FragData[maxDrawBuffers-1]
+// with gl_FragData[0].
+//
+
+#include "compiler/translator/EmulateGLFragColorBroadcast.h"
+
+#include "compiler/translator/IntermNode_util.h"
+#include "compiler/translator/IntermTraverse.h"
+#include "compiler/translator/RunAtTheEndOfShader.h"
+
+namespace sh
+{
+
+namespace
+{
+
+class GLFragColorBroadcastTraverser : public TIntermTraverser
+{
+  public:
+    GLFragColorBroadcastTraverser(int maxDrawBuffers, TSymbolTable *symbolTable, int shaderVersion)
+        : TIntermTraverser(true, false, false, symbolTable),
+          mGLFragColorUsed(false),
+          mMaxDrawBuffers(maxDrawBuffers),
+          mShaderVersion(shaderVersion)
+    {
+    }
+
+    void broadcastGLFragColor(TIntermBlock *root);
+
+    bool isGLFragColorUsed() const { return mGLFragColorUsed; }
+
+  protected:
+    void visitSymbol(TIntermSymbol *node) override;
+
+    TIntermBinary *constructGLFragDataNode(int index) const;
+    TIntermBinary *constructGLFragDataAssignNode(int index) const;
+
+  private:
+    bool mGLFragColorUsed;
+    int mMaxDrawBuffers;
+    const int mShaderVersion;
+};
+
+TIntermBinary *GLFragColorBroadcastTraverser::constructGLFragDataNode(int index) const
+{
+    TIntermSymbol *symbol =
+        ReferenceBuiltInVariable(TString("gl_FragData"), *mSymbolTable, mShaderVersion);
+    TIntermTyped *indexNode = CreateIndexNode(index);
+
+    TIntermBinary *binary = new TIntermBinary(EOpIndexDirect, symbol, indexNode);
+    return binary;
+}
+
+TIntermBinary *GLFragColorBroadcastTraverser::constructGLFragDataAssignNode(int index) const
+{
+    TIntermTyped *fragDataIndex = constructGLFragDataNode(index);
+    TIntermTyped *fragDataZero  = constructGLFragDataNode(0);
+
+    return new TIntermBinary(EOpAssign, fragDataIndex, fragDataZero);
+}
+
+void GLFragColorBroadcastTraverser::visitSymbol(TIntermSymbol *node)
+{
+    if (node->getSymbol() == "gl_FragColor")
+    {
+        queueReplacement(constructGLFragDataNode(0), OriginalNode::IS_DROPPED);
+        mGLFragColorUsed = true;
+    }
+}
+
+void GLFragColorBroadcastTraverser::broadcastGLFragColor(TIntermBlock *root)
+{
+    ASSERT(mMaxDrawBuffers > 1);
+    if (!mGLFragColorUsed)
+    {
+        return;
+    }
+
+    TIntermBlock *broadcastBlock = new TIntermBlock();
+    // Now insert statements
+    //   gl_FragData[1] = gl_FragData[0];
+    //   ...
+    //   gl_FragData[maxDrawBuffers - 1] = gl_FragData[0];
+    for (int colorIndex = 1; colorIndex < mMaxDrawBuffers; ++colorIndex)
+    {
+        broadcastBlock->appendStatement(constructGLFragDataAssignNode(colorIndex));
+    }
+    RunAtTheEndOfShader(root, broadcastBlock, mSymbolTable);
+}
+
+}  // namespace anonymous
+
+void EmulateGLFragColorBroadcast(TIntermBlock *root,
+                                 int maxDrawBuffers,
+                                 std::vector<sh::OutputVariable> *outputVariables,
+                                 TSymbolTable *symbolTable,
+                                 int shaderVersion)
+{
+    ASSERT(maxDrawBuffers > 1);
+    GLFragColorBroadcastTraverser traverser(maxDrawBuffers, symbolTable, shaderVersion);
+    root->traverse(&traverser);
+    if (traverser.isGLFragColorUsed())
+    {
+        traverser.updateTree();
+        traverser.broadcastGLFragColor(root);
+        for (auto &var : *outputVariables)
+        {
+            if (var.name == "gl_FragColor")
+            {
+                // TODO(zmo): Find a way to keep the original variable information.
+                var.name       = "gl_FragData";
+                var.mappedName = "gl_FragData";
+                var.arraySizes.push_back(maxDrawBuffers);
+                ASSERT(var.arraySizes.size() == 1u);
+            }
+        }
+    }
+}
+
+}  // namespace sh