Make GL_EXT_blend_minmax enableable.

src/libANGLE/Caps.cpp

@@ -653,7 +653,7 @@ const ExtensionInfoMap &GetExtensionInfoMap()
         map["GL_EXT_disjoint_timer_query"] = esOnlyExtension(&Extensions::disjointTimerQuery);
         map["GL_EXT_robustness"] = esOnlyExtension(&Extensions::robustness);
         map["GL_KHR_robust_buffer_access_behavior"] = esOnlyExtension(&Extensions::robustBufferAccessBehavior);
-        map["GL_EXT_blend_minmax"] = esOnlyExtension(&Extensions::blendMinMax);
+        map["GL_EXT_blend_minmax"] = enableableExtension(&Extensions::blendMinMax);
         map["GL_ANGLE_framebuffer_blit"] = esOnlyExtension(&Extensions::framebufferBlit);
         map["GL_ANGLE_framebuffer_multisample"] = esOnlyExtension(&Extensions::framebufferMultisample);
         map["GL_ANGLE_instanced_arrays"] = esOnlyExtension(&Extensions::instancedArrays);

src/libANGLE/validationES2.cpp

@@ -4398,16 +4398,18 @@ bool ValidateBindRenderbuffer(ValidationContext *context, GLenum target, GLuint
     return true;
 }
 
-static bool ValidBlendEquationMode(GLenum mode)
+static bool ValidBlendEquationMode(const ValidationContext *context, GLenum mode)
 {
     switch (mode)
     {
         case GL_FUNC_ADD:
         case GL_FUNC_SUBTRACT:
         case GL_FUNC_REVERSE_SUBTRACT:
+            return true;
+
         case GL_MIN:
         case GL_MAX:
-            return true;
+            return context->getClientVersion() >= ES_3_0 || context->getExtensions().blendMinMax;
 
         default:
             return false;
@@ -4425,7 +4427,7 @@ bool ValidateBlendColor(ValidationContext *context,
 
 bool ValidateBlendEquation(ValidationContext *context, GLenum mode)
 {
-    if (!ValidBlendEquationMode(mode))
+    if (!ValidBlendEquationMode(context, mode))
     {
         ANGLE_VALIDATION_ERR(context, InvalidEnum(), InvalidBlendEquation);
         return false;
@@ -4436,13 +4438,13 @@ bool ValidateBlendEquation(ValidationContext *context, GLenum mode)
 
 bool ValidateBlendEquationSeparate(ValidationContext *context, GLenum modeRGB, GLenum modeAlpha)
 {
-    if (!ValidBlendEquationMode(modeRGB))
+    if (!ValidBlendEquationMode(context, modeRGB))
     {
         ANGLE_VALIDATION_ERR(context, InvalidEnum(), InvalidBlendEquation);
         return false;
     }
 
-    if (!ValidBlendEquationMode(modeAlpha))
+    if (!ValidBlendEquationMode(context, modeAlpha))
     {
         ANGLE_VALIDATION_ERR(context, InvalidEnum(), InvalidBlendEquation);
         return false;

src/tests/gl_tests/WebGLCompatibilityTest.cpp

@@ -552,6 +552,31 @@ TEST_P(WebGLCompatibilityTest, EnableRenderMipmapExtension)
     }
 }
 
+// Test enabling the GL_EXT_blend_minmax extension
+TEST_P(WebGLCompatibilityTest, EnableBlendMinMaxExtension)
+{
+    EXPECT_FALSE(extensionEnabled("GL_EXT_blend_minmax"));
+
+    // This extensions become core in in ES3/WebGL2.
+    ANGLE_SKIP_TEST_IF(getClientMajorVersion() >= 3);
+
+    glBlendEquation(GL_MIN);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+
+    glBlendEquation(GL_MAX);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+
+    if (extensionRequestable("GL_EXT_blend_minmax"))
+    {
+        glRequestExtensionANGLE("GL_EXT_blend_minmax");
+        EXPECT_GL_NO_ERROR();
+
+        glBlendEquation(GL_MIN);
+        glBlendEquation(GL_MAX);
+        EXPECT_GL_NO_ERROR();
+    }
+}
+
 // Verify that the context generates the correct error when the framebuffer attachments are
 // different sizes
 TEST_P(WebGLCompatibilityTest, FramebufferAttachmentSizeMissmatch)