ASTMetadataHLSL: handle WebGL2 gradient builtins

src/compiler/translator/ASTMetadataHLSL.cpp

@@ -32,6 +32,19 @@ class PullGradient : public TIntermTraverser
           mDag(dag)
     {
         ASSERT(index < metadataList->size());
+
+        // ESSL 100 builtin gradient functions
+        mGradientBuiltinFunctions.insert("texture2D");
+        mGradientBuiltinFunctions.insert("texture2DProj");
+        mGradientBuiltinFunctions.insert("textureCube");
+
+        // ESSL 300 builtin gradient functions
+        mGradientBuiltinFunctions.insert("texture");
+        mGradientBuiltinFunctions.insert("textureProj");
+        mGradientBuiltinFunctions.insert("textureOffset");
+        mGradientBuiltinFunctions.insert("textureProjOffset");
+
+        // ESSL 310 doesn't add builtin gradient functions
     }
 
     void traverse(TIntermFunctionDefinition *node)
@@ -89,6 +102,7 @@ class PullGradient : public TIntermTraverser
             {
                 case EOpDFdx:
                 case EOpDFdy:
+                case EOpFwidth:
                     onGradient();
                 default:
                     break;
@@ -116,7 +130,7 @@ class PullGradient : public TIntermTraverser
             {
                 TString name = TFunction::unmangleName(node->getFunctionSymbolInfo()->getName());
 
-                if (name == "texture2D" || name == "texture2DProj" || name == "textureCube")
+                if (mGradientBuiltinFunctions.find(name) != mGradientBuiltinFunctions.end())
                 {
                     onGradient();
                 }
@@ -135,6 +149,9 @@ class PullGradient : public TIntermTraverser
     // Contains a stack of the control flow nodes that are parents of the node being
     // currently visited. It is used to mark control flows using a gradient.
     std::vector<TIntermNode *> mParents;
+
+    // A list of builtin functions that use gradients
+    std::set<TString> mGradientBuiltinFunctions;
 };
 
 // Traverses the AST of a function definition to compute the the discontinuous loops

src/tests/compiler_tests/UnrollFlatten_test.cpp

@@ -22,21 +22,22 @@ namespace
 class UnrollFlattenTest : public testing::Test
 {
   public:
-    UnrollFlattenTest() {}
+    UnrollFlattenTest() : mInputSpec(SH_GLES2_SPEC) {}
+    UnrollFlattenTest(ShShaderSpec inputSpec) : mInputSpec(inputSpec) {}
 
   protected:
     void compile(const std::string &shaderString)
     {
         std::string infoLog;
         bool compilationSuccess =
-            compileTestShader(GL_FRAGMENT_SHADER, SH_GLES2_SPEC, SH_HLSL_4_1_OUTPUT, shaderString,
+            compileTestShader(GL_FRAGMENT_SHADER, mInputSpec, SH_HLSL_4_1_OUTPUT, shaderString,
                               SH_VARIABLES, &mTranslatedSource, &infoLog);
         if (!compilationSuccess)
         {
             FAIL() << "Shader compilation failed " << infoLog;
         }
         // Ignore the beginning of the shader to avoid the definitions of LOOP and FLATTEN
-        mCurrentPosition = static_cast<int>(mTranslatedSource.find("GL_USES_FRAG_COLOR"));
+        mCurrentPosition = static_cast<int>(mTranslatedSource.find("cbuffer DriverConstants"));
     }
 
     void expect(const char *patterns[], size_t count)
@@ -71,6 +72,7 @@ class UnrollFlattenTest : public testing::Test
     static const char *FLATTEN;
 
   private:
+    ShShaderSpec mInputSpec;
     std::string mTranslatedSource;
 
     int mCurrentPosition;
@@ -206,4 +208,31 @@ TEST_F(UnrollFlattenTest, GradientInDiscont)
     expect(expectations, ArraySize(expectations));
 }
 
+class UnrollFlattenTest_ES3 : public UnrollFlattenTest
+{
+  public:
+    UnrollFlattenTest_ES3() : UnrollFlattenTest(SH_GLES3_SPEC) {}
+};
+
+// Check that we correctly detect the ES3 builtin "texture" function as a gradient operation.
+TEST_F(UnrollFlattenTest_ES3, TextureBuiltin)
+{
+    const std::string &shaderString =
+        "#version 300 es\n"
+        "precision mediump float;\n"
+        "uniform sampler2D tex;"
+        "out float fragColor;\n"
+        "void main() {\n"
+        "    float a = 0.0;"
+        "    for (int i = 0; i < 10; i++) {\n"
+        "        if (a > 1.0) {break;}\n"
+        "        a += texture(tex, vec2(a, 0.0)).x;"
+        "    }\n"
+        "    fragColor = a;\n"
+        "}\n";
+
+    compile(shaderString);
+    const char *expectations[] = {"main(", "LOOP", "Lod0("};
+    expect(expectations, ArraySize(expectations));
+}
 }