add ext_float_blend feature and test

Bug: chromium:930993
Change-Id: I8edbd01c5c9f1ed63243cc4a42f6de44c92db8bd
Reviewed-on: https://chromium-review.googlesource.com/c/1481242
Commit-Queue: Shrek Shao <shrekshao@google.com>
Reviewed-by: Jamie Madill <jmadill@google.com>

src/libANGLE/Caps.cpp

@@ -255,6 +255,7 @@ Extensions::Extensions()
       multiviewMultisample(false),
       blendFuncExtended(false),
       maxDualSourceDrawBuffers(0),
+      floatBlend(false),
       memorySize(false),
       textureMultisample(false),
       multiDraw(false)
@@ -909,6 +910,7 @@ const ExtensionInfoMap &GetExtensionInfoMap()
         map["GL_OES_texture_storage_multisample_2d_array"] = enableableExtension(&Extensions::textureStorageMultisample2DArray);
         map["GL_ANGLE_multiview_multisample"] = enableableExtension(&Extensions::multiviewMultisample);
         map["GL_EXT_blend_func_extended"] = enableableExtension(&Extensions::blendFuncExtended);
+        map["GL_EXT_float_blend"] = enableableExtension(&Extensions::floatBlend);
         map["GL_ANGLE_texture_multisample"] = enableableExtension(&Extensions::textureMultisample);
         map["GL_ANGLE_multi_draw"] = enableableExtension(&Extensions::multiDraw);
         map["GL_ANGLE_provoking_vertex"] = enableableExtension(&Extensions::provokingVertex);

src/libANGLE/Caps.h

@@ -466,6 +466,9 @@ struct Extensions
     bool blendFuncExtended;
     GLuint maxDualSourceDrawBuffers;
 
+    // GL_EXT_float_blend
+    bool floatBlend;
+
     // GL_ANGLE_memory_size
     bool memorySize;
 

src/libANGLE/ErrorStrings.h

@@ -474,6 +474,7 @@ MSG kUnimplementedComputeShaderPrecision = "Compute shader precision not yet imp
 MSG kUnknownParameter = "Unknown parameter value.";
 MSG kUnsizedInternalFormatUnsupported = "Internalformat is one of the unsupported unsized base internalformats.";
 MSG kUnsupportedDrawModeForTransformFeedback = "The draw command is unsupported when transform feedback is active and not paused.";
+MSG kUnsupportedFloatBlending = "GL_BLEND with floating-point color attachments requires the EXT_float_blend extension.";
 MSG kVertexArrayNoBuffer = "An enabled vertex array has no buffer.";
 MSG kVertexArrayNoBufferPointer = "An enabled vertex array has no buffer and no pointer.";
 MSG kVertexBufferBoundForTransformFeedback = "It is undefined behavior to use a vertex buffer that is bound for transform feedback.";

src/libANGLE/Framebuffer.cpp

@@ -1758,6 +1758,16 @@ void Framebuffer::setAttachmentImpl(const Context *context,
                              textureIndex, resource, numViews, baseViewIndex, multiviewLayout,
                              viewportOffsets);
 
+            if (!resource)
+            {
+                mFloat32ColorAttachmentBits.reset(colorIndex);
+            }
+            else
+            {
+                updateFloat32ColorAttachmentBits(
+                    colorIndex, resource->getAttachmentFormat(binding, textureIndex).info);
+            }
+
             // TODO(jmadill): ASSERT instead of checking the attachment exists in
             // formsRenderingFeedbackLoopWith
             bool enabled = (type != GL_NONE && getDrawBufferState(colorIndex) != GL_NONE);
@@ -1829,6 +1839,15 @@ void Framebuffer::onSubjectStateChange(const Context *context,
 
     // Mark the appropriate init flag.
     mState.mResourceNeedsInit.set(index, attachment->initState() == InitState::MayNeedInit);
+
+    // Update mFloat32ColorAttachmentBits Cache
+    if (index < DIRTY_BIT_COLOR_ATTACHMENT_MAX)
+    {
+        ASSERT(index != DIRTY_BIT_DEPTH_ATTACHMENT);
+        ASSERT(index != DIRTY_BIT_STENCIL_ATTACHMENT);
+        updateFloat32ColorAttachmentBits(index - DIRTY_BIT_COLOR_ATTACHMENT_0,
+                                         attachment->getFormat().info);
+    }
 }
 
 FramebufferAttachment *Framebuffer::getAttachmentFromSubjectIndex(angle::SubjectIndex index)

src/libANGLE/Framebuffer.h

@@ -337,6 +337,11 @@ class Framebuffer final : public angle::ObserverInterface,
     using DirtyBits = angle::BitSet<DIRTY_BIT_MAX>;
     bool hasAnyDirtyBit() const { return mDirtyBits.any(); }
 
+    bool hasActiveFloat32ColorAttachment() const
+    {
+        return (mFloat32ColorAttachmentBits & getDrawBufferMask()).any();
+    }
+
     bool hasResourceThatNeedsInit() const { return mState.mResourceNeedsInit.any(); }
 
     angle::Result syncState(const Context *context);
@@ -418,6 +423,12 @@ class Framebuffer final : public angle::ObserverInterface,
 
     FramebufferAttachment *getAttachmentFromSubjectIndex(angle::SubjectIndex index);
 
+    ANGLE_INLINE void updateFloat32ColorAttachmentBits(size_t index,
+                                                       const gl::InternalFormat *format)
+    {
+        mFloat32ColorAttachmentBits.set(index, format->type == GL_FLOAT);
+    }
+
     FramebufferState mState;
     rx::FramebufferImpl *mImpl;
 
@@ -427,6 +438,7 @@ class Framebuffer final : public angle::ObserverInterface,
     angle::ObserverBinding mDirtyStencilAttachmentBinding;
 
     DirtyBits mDirtyBits;
+    DrawBufferMask mFloat32ColorAttachmentBits;
 
     // The dirty bits guard is checked when we get a dependent state change message. We verify that
     // we don't set a dirty bit that isn't already set, when inside the dirty bits syncState.

src/libANGLE/renderer/gl/renderergl_utils.cpp

@@ -1345,6 +1345,11 @@ void GenerateCaps(const FunctionsGL *functions,
         extensions->maxDualSourceDrawBuffers = 1;
     }
 
+    // EXT_float_blend
+    // Assume all desktop driver supports this by default.
+    extensions->floatBlend = functions->standard == STANDARD_GL_DESKTOP ||
+                             functions->hasGLESExtension("GL_EXT_float_blend");
+
     // GL_CHROMIUM_compressed_texture_etc
     // Expose this extension only when we support the formats or we're running on top of a native
     // ES driver.

src/libANGLE/validationES.cpp

@@ -2623,6 +2623,12 @@ const char *ValidateDrawStates(Context *context)
         }
     }
 
+    if (!extensions.floatBlend && context->getState().isBlendEnabled() &&
+        framebuffer->hasActiveFloat32ColorAttachment())
+    {
+        return kUnsupportedFloatBlending;
+    }
+
     if (!framebuffer->isComplete(context))
     {
         // Note: this error should be generated as INVALID_FRAMEBUFFER_OPERATION.

src/tests/gl_tests/BlendMinMaxTest.cpp

@@ -171,7 +171,7 @@ TEST_P(BlendMinMaxTest, RGBA8)
 
 TEST_P(BlendMinMaxTest, RGBA32F)
 {
-    ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3 ||
+    ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3 || !extensionEnabled("GL_EXT_float_blend") ||
                        !extensionEnabled("GL_EXT_color_buffer_float"));
 
     // Ignore SDK layers messages on D3D11 FL 9.3 (http://anglebug.com/1284)