Implement EXT_discard_framebuffer in D3D11 renderer

src/libANGLE/Caps.cpp

@@ -134,6 +134,7 @@ Extensions::Extensions()
       textureUsage(false),
       translatedShaderSource(false),
       fboRenderMipmap(false),
+      discardFramebuffer(false),
       colorBufferFloat(false)
 {
 }
@@ -184,6 +185,7 @@ std::vector<std::string> Extensions::getStrings() const
     InsertExtensionString("GL_ANGLE_texture_usage",            textureUsage,             &extensionStrings);
     InsertExtensionString("GL_ANGLE_translated_shader_source", translatedShaderSource,   &extensionStrings);
     InsertExtensionString("GL_OES_fbo_render_mipmap",          fboRenderMipmap,          &extensionStrings);
+    InsertExtensionString("GL_EXT_discard_framebuffer",        discardFramebuffer,       &extensionStrings);
     InsertExtensionString("GL_EXT_color_buffer_float",         colorBufferFloat,         &extensionStrings);
 
     return extensionStrings;

src/libANGLE/Caps.h

@@ -213,6 +213,9 @@ struct Extensions
     // GL_OES_fbo_render_mipmap
     bool fboRenderMipmap;
 
+    // GL_EXT_discard_framebuffer
+    bool discardFramebuffer;
+
     // ES3 Extension support
 
     // GL_EXT_color_buffer_float

src/libANGLE/Framebuffer.cpp

@@ -497,6 +497,11 @@ GLenum Framebuffer::checkStatus(const gl::Data &data) const
     return mImpl->checkStatus();
 }
 
+Error Framebuffer::discard(size_t count, const GLenum *attachments)
+{
+    return mImpl->discard(count, attachments);
+}
+
 Error Framebuffer::invalidate(size_t count, const GLenum *attachments)
 {
     return mImpl->invalidate(count, attachments);

src/libANGLE/Framebuffer.h

@@ -118,6 +118,7 @@ class Framebuffer
     GLenum checkStatus(const gl::Data &data) const;
     bool hasValidDepthStencil() const;
 
+    Error discard(size_t count, const GLenum *attachments);
     Error invalidate(size_t count, const GLenum *attachments);
     Error invalidateSub(size_t count, const GLenum *attachments, const gl::Rectangle &area);
 

src/libANGLE/renderer/FramebufferImpl.h

@@ -39,6 +39,7 @@ class FramebufferImpl : angle::NonCopyable
     virtual void setDrawBuffers(size_t count, const GLenum *buffers) = 0;
     virtual void setReadBuffer(GLenum buffer) = 0;
 
+    virtual gl::Error discard(size_t count, const GLenum *attachments) = 0;
     virtual gl::Error invalidate(size_t count, const GLenum *attachments) = 0;
     virtual gl::Error invalidateSub(size_t count, const GLenum *attachments, const gl::Rectangle &area) = 0;
 

src/libANGLE/renderer/d3d/FramebufferD3D.cpp

@@ -123,18 +123,6 @@ void FramebufferD3D::setReadBuffer(GLenum)
 {
 }
 
-gl::Error FramebufferD3D::invalidate(size_t, const GLenum *)
-{
-    // No-op in D3D
-    return gl::Error(GL_NO_ERROR);
-}
-
-gl::Error FramebufferD3D::invalidateSub(size_t, const GLenum *, const gl::Rectangle &)
-{
-    // No-op in D3D
-    return gl::Error(GL_NO_ERROR);
-}
-
 gl::Error FramebufferD3D::clear(const gl::Data &data, GLbitfield mask)
 {
     const gl::State &state = *data.state;

src/libANGLE/renderer/d3d/FramebufferD3D.h

@@ -66,9 +66,6 @@ class FramebufferD3D : public FramebufferImpl
     void setDrawBuffers(size_t count, const GLenum *buffers) override;
     void setReadBuffer(GLenum buffer) override;
 
-    gl::Error invalidate(size_t count, const GLenum *attachments) override;
-    gl::Error invalidateSub(size_t count, const GLenum *attachments, const gl::Rectangle &area) override;
-
     gl::Error clear(const gl::Data &data, GLbitfield mask) override;
     gl::Error clearBufferfv(const gl::State &state, GLenum buffer, GLint drawbuffer, const GLfloat *values) override;
     gl::Error clearBufferuiv(const gl::State &state, GLenum buffer, GLint drawbuffer, const GLuint *values) override;

src/libANGLE/renderer/d3d/d3d11/Framebuffer11.cpp

@@ -135,6 +135,159 @@ static gl::Error getRenderTargetResource(const gl::FramebufferAttachment *colorb
     return gl::Error(GL_NO_ERROR);
 }
 
+gl::Error Framebuffer11::invalidate(size_t count, const GLenum *attachments)
+{
+    return invalidateBase(count, attachments, false);
+}
+
+gl::Error Framebuffer11::discard(size_t count, const GLenum *attachments)
+{
+    return invalidateBase(count, attachments, true);
+}
+
+gl::Error Framebuffer11::invalidateBase(size_t count, const GLenum *attachments, bool useEXTBehavior) const
+{
+    ID3D11DeviceContext1 *deviceContext1 = mRenderer->getDeviceContext1IfSupported();
+
+    if (!deviceContext1)
+    {
+        // DiscardView() is only supported on ID3D11DeviceContext1
+        return gl::Error(GL_NO_ERROR);
+    }
+
+    bool foundDepth = false;
+    bool foundStencil = false;
+
+    for (size_t i = 0; i < count; ++i)
+    {
+        switch (attachments[i])
+        {
+          // Handle depth and stencil attachments. Defer discarding until later.
+          case GL_DEPTH_STENCIL_ATTACHMENT:
+            foundDepth = true;
+            foundStencil = true;
+            break;
+          case GL_DEPTH_EXT:
+          case GL_DEPTH_ATTACHMENT:
+            foundDepth = true;
+            break;
+          case GL_STENCIL_EXT:
+          case GL_STENCIL_ATTACHMENT:
+            foundStencil = true;
+            break;
+          default:
+            {
+                // Handle color attachments
+                ASSERT((attachments[i] >= GL_COLOR_ATTACHMENT0 && attachments[i] <= GL_COLOR_ATTACHMENT15) ||
+                       (attachments[i] == GL_COLOR));
+
+                RenderTarget11 *renderTarget = nullptr;
+                ID3D11View *colorView = nullptr;
+                gl::Error error(GL_NO_ERROR);
+                size_t colorAttachmentID = 0;
+
+                if (attachments[i] == GL_COLOR)
+                {
+                    colorAttachmentID = 0;
+                }
+                else
+                {
+                    colorAttachmentID = attachments[i] - GL_COLOR_ATTACHMENT0;
+                }
+
+                if (mData.getColorAttachment(colorAttachmentID))
+                {
+                    error = mData.getColorAttachment(colorAttachmentID)->getRenderTarget(&renderTarget);
+                    if (error.isError())
+                    {
+                        return error;
+                    }
+
+                    colorView = renderTarget->getRenderTargetView();
+
+                    if (colorView != nullptr)
+                    {
+                        deviceContext1->DiscardView(colorView);
+                    }
+                }
+
+                break;
+            }
+        }
+    }
+
+    bool discardDepth = false;
+    bool discardStencil = false;
+
+    // The D3D11 renderer uses the same view for depth and stencil buffers, so we must be careful.
+    if (useEXTBehavior)
+    {
+        // In the extension, if the app discards only one of the depth and stencil attachments, but
+        // those are backed by the same packed_depth_stencil buffer, then both images become undefined.
+        discardDepth = foundDepth;
+
+        // Don't bother discarding the stencil buffer if the depth buffer will already do it
+        discardStencil = foundStencil && (!discardDepth || mData.getDepthAttachment() == nullptr);
+    }
+    else
+    {
+        // In ES 3.0.4, if a specified attachment has base internal format DEPTH_STENCIL but the
+        // attachments list does not include DEPTH_STENCIL_ATTACHMENT or both DEPTH_ATTACHMENT and
+        // STENCIL_ATTACHMENT, then only the specified portion of every pixel in the subregion of pixels
+        // of the DEPTH_STENCIL buffer may be invalidated, and the other portion must be preserved.
+        discardDepth = (foundDepth && foundStencil) || (foundDepth && (mData.getStencilAttachment() == nullptr));
+        discardStencil = (foundStencil && (mData.getDepthAttachment() == nullptr));
+    }
+
+    if (discardDepth && mData.getDepthAttachment())
+    {
+        RenderTarget11 *renderTarget = nullptr;
+        ID3D11View *depthView = nullptr;
+        gl::Error error(GL_NO_ERROR);
+
+        error = mData.getDepthAttachment()->getRenderTarget(&renderTarget);
+        if (error.isError())
+        {
+            return error;
+        }
+
+        depthView = renderTarget->getDepthStencilView();
+
+        if (depthView != nullptr)
+        {
+            deviceContext1->DiscardView(depthView);
+        }
+    }
+
+    if (discardStencil && mData.getStencilAttachment())
+    {
+        RenderTarget11 *renderTarget = nullptr;
+        ID3D11View *stencilView = nullptr;
+        gl::Error error(GL_NO_ERROR);
+
+        error = mData.getStencilAttachment()->getRenderTarget(&renderTarget);
+        if (error.isError())
+        {
+            return error;
+        }
+
+        stencilView = renderTarget->getDepthStencilView();
+
+        if (stencilView != nullptr)
+        {
+            deviceContext1->DiscardView(stencilView);
+        }
+    }
+
+    return gl::Error(GL_NO_ERROR);
+}
+
+gl::Error Framebuffer11::invalidateSub(size_t, const GLenum *, const gl::Rectangle &)
+{
+    // A no-op implementation conforms to the spec, so don't call UNIMPLEMENTED()
+    return gl::Error(GL_NO_ERROR);
+}
+
 gl::Error Framebuffer11::readPixels(const gl::Rectangle &area, GLenum format, GLenum type, size_t outputPitch, const gl::PixelPackState &pack, uint8_t *pixels) const
 {
     ID3D11Texture2D *colorBufferTexture = nullptr;

src/libANGLE/renderer/d3d/d3d11/Framebuffer11.h

@@ -21,6 +21,10 @@ class Framebuffer11 : public FramebufferD3D
     Framebuffer11(const gl::Framebuffer::Data &data, Renderer11 *renderer);
     virtual ~Framebuffer11();
 
+    gl::Error discard(size_t count, const GLenum *attachments) override;
+    gl::Error invalidate(size_t count, const GLenum *attachments) override;
+    gl::Error invalidateSub(size_t count, const GLenum *attachments, const gl::Rectangle &area) override;
+
     // Invalidate the cached swizzles of all bound texture attachments.
     gl::Error invalidateSwizzles() const;
 
@@ -34,6 +38,7 @@ class Framebuffer11 : public FramebufferD3D
                    bool blitRenderTarget, bool blitDepth, bool blitStencil, GLenum filter,
                    const gl::Framebuffer *sourceFramebuffer) override;
 
+    gl::Error invalidateBase(size_t count, const GLenum *attachments, bool useEXTBehavior) const;
 
     GLenum getRenderTargetImplementationFormat(RenderTargetD3D *renderTarget) const override;
 

src/libANGLE/renderer/d3d/d3d11/renderer11_utils.cpp

@@ -1102,6 +1102,7 @@ void GenerateCaps(ID3D11Device *device, ID3D11DeviceContext *deviceContext, cons
     extensions->shaderTextureLOD = GetShaderTextureLODSupport(featureLevel);
     extensions->fragDepth = true;
     extensions->textureUsage = true; // This could be false since it has no effect in D3D11
+    extensions->discardFramebuffer = false; // TODO: enable this once BUG:497445 is fixed (Chrome WebGL video tests fail with this extension active)
     extensions->translatedShaderSource = true;
     extensions->fboRenderMipmap = false;
 }

src/libANGLE/renderer/d3d/d3d9/Framebuffer9.cpp

@@ -32,6 +32,27 @@ Framebuffer9::~Framebuffer9()
 {
 }
 
+gl::Error Framebuffer9::discard(size_t, const GLenum *)
+{
+    // Extension not implemented in D3D9 renderer
+    UNREACHABLE();
+    return gl::Error(GL_NO_ERROR);
+}
+
+gl::Error Framebuffer9::invalidate(size_t, const GLenum *)
+{
+    // Shouldn't ever reach here in D3D9
+    UNREACHABLE();
+    return gl::Error(GL_NO_ERROR);
+}
+
+gl::Error Framebuffer9::invalidateSub(size_t, const GLenum *, const gl::Rectangle &)
+{
+    // Shouldn't ever reach here in D3D9
+    UNREACHABLE();
+    return gl::Error(GL_NO_ERROR);
+}
+
 gl::Error Framebuffer9::clear(const gl::State &state, const ClearParameters &clearParams)
 {
     const gl::FramebufferAttachment *colorAttachment = mData.getColorAttachment(0);

src/libANGLE/renderer/d3d/d3d9/Framebuffer9.h

@@ -21,6 +21,10 @@ class Framebuffer9 : public FramebufferD3D
     Framebuffer9(const gl::Framebuffer::Data &data, Renderer9 *renderer);
     virtual ~Framebuffer9();
 
+    gl::Error discard(size_t count, const GLenum *attachments) override;
+    gl::Error invalidate(size_t count, const GLenum *attachments) override;
+    gl::Error invalidateSub(size_t count, const GLenum *attachments, const gl::Rectangle &area) override;
+
   private:
     gl::Error clear(const gl::State &state, const ClearParameters &clearParams) override;
 

src/libANGLE/renderer/d3d/d3d9/renderer9_utils.cpp

@@ -538,6 +538,7 @@ void GenerateCaps(IDirect3D9 *d3d9, IDirect3DDevice9 *device, D3DDEVTYPE deviceT
     extensions->textureUsage = true;
     extensions->translatedShaderSource = true;
     extensions->fboRenderMipmap = false;
+    extensions->discardFramebuffer = false; // It would be valid to set this to true, since glDiscardFramebufferEXT is just a hint
     extensions->colorBufferFloat = false;
 }
 

src/libANGLE/renderer/gl/FramebufferGL.cpp

@@ -152,6 +152,12 @@ void FramebufferGL::setReadBuffer(GLenum buffer)
     }
 }
 
+gl::Error FramebufferGL::discard(size_t count, const GLenum *attachments)
+{
+    UNIMPLEMENTED();
+    return gl::Error(GL_INVALID_OPERATION);
+}
+
 gl::Error FramebufferGL::invalidate(size_t count, const GLenum *attachments)
 {
     // Since this function is just a hint and not available until OpenGL 4.3, only call it if it is available.

src/libANGLE/renderer/gl/FramebufferGL.h

@@ -31,6 +31,7 @@ class FramebufferGL : public FramebufferImpl
     void setDrawBuffers(size_t count, const GLenum *buffers) override;
     void setReadBuffer(GLenum buffer) override;
 
+    gl::Error discard(size_t count, const GLenum *attachments) override;
     gl::Error invalidate(size_t count, const GLenum *attachments) override;
     gl::Error invalidateSub(size_t count, const GLenum *attachments, const gl::Rectangle &area) override;
 

src/libANGLE/validationES.cpp

@@ -1884,4 +1884,62 @@ bool ValidateGetnUniformivEXT(Context *context, GLuint program, GLint location,
     return ValidateSizedGetUniform(context, program, location, bufSize);
 }
 
+bool ValidateDiscardFramebufferBase(Context *context, GLenum target, GLsizei numAttachments,
+                                    const GLenum *attachments, bool defaultFramebuffer)
+{
+    if (numAttachments < 0)
+    {
+        context->recordError(Error(GL_INVALID_VALUE, "numAttachments must not be less than zero"));
+        return false;
+    }
+
+    for (GLsizei i = 0; i < numAttachments; ++i)
+    {
+        if (attachments[i] >= GL_COLOR_ATTACHMENT0 && attachments[i] <= GL_COLOR_ATTACHMENT15)
+        {
+            if (defaultFramebuffer)
+            {
+                context->recordError(Error(GL_INVALID_ENUM, "Invalid attachment when the default framebuffer is bound"));
+                return false;
+            }
+
+            if (attachments[i] >= GL_COLOR_ATTACHMENT0 + context->getCaps().maxColorAttachments)
+            {
+                context->recordError(Error(GL_INVALID_OPERATION,
+                                           "Requested color attachment is greater than the maximum supported color attachments"));
+                return false;
+            }
+        }
+        else
+        {
+            switch (attachments[i])
+            {
+              case GL_DEPTH_ATTACHMENT:
+              case GL_STENCIL_ATTACHMENT:
+              case GL_DEPTH_STENCIL_ATTACHMENT:
+                if (defaultFramebuffer)
+                {
+                    context->recordError(Error(GL_INVALID_ENUM, "Invalid attachment when the default framebuffer is bound"));
+                    return false;
+                }
+                break;
+              case GL_COLOR:
+              case GL_DEPTH:
+              case GL_STENCIL:
+                if (!defaultFramebuffer)
+                {
+                    context->recordError(Error(GL_INVALID_ENUM, "Invalid attachment when the default framebuffer is not bound"));
+                    return false;
+                }
+                break;
+              default:
+                context->recordError(Error(GL_INVALID_ENUM, "Invalid attachment"));
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
+
 }

src/libANGLE/validationES.h

@@ -89,6 +89,9 @@ bool ValidateGetUniformiv(Context *context, GLuint program, GLint location, GLin
 bool ValidateGetnUniformfvEXT(Context *context, GLuint program, GLint location, GLsizei bufSize, GLfloat* params);
 bool ValidateGetnUniformivEXT(Context *context, GLuint program, GLint location, GLsizei bufSize, GLint* params);
 
+bool ValidateDiscardFramebufferBase(Context *context, GLenum target, GLsizei numAttachments,
+                                    const GLenum *attachments, bool defaultFramebuffer);
+
 }
 
 #endif // LIBANGLE_VALIDATION_ES_H_

src/libANGLE/validationES2.cpp

@@ -879,4 +879,22 @@ bool ValidES2ReadFormatType(Context *context, GLenum format, GLenum type)
     return true;
 }
 
+bool ValidateDiscardFramebufferEXT(Context *context, GLenum target, GLsizei numAttachments,
+                                   const GLenum *attachments)
+{
+    bool defaultFramebuffer = false;
+
+    switch (target)
+    {
+      case GL_FRAMEBUFFER:
+        defaultFramebuffer = (context->getState().getTargetFramebuffer(GL_FRAMEBUFFER)->id() == 0);
+        break;
+      default:
+        context->recordError(Error(GL_INVALID_ENUM, "Invalid framebuffer target"));
+        return false;
+    }
+
+    return ValidateDiscardFramebufferBase(context, target, numAttachments, attachments, defaultFramebuffer);
+}
+
 }

src/libANGLE/validationES2.h

@@ -29,6 +29,9 @@ bool ValidateES2TexStorageParameters(Context *context, GLenum target, GLsizei le
 
 bool ValidES2ReadFormatType(Context *context, GLenum format, GLenum type);
 
+bool ValidateDiscardFramebufferEXT(Context *context, GLenum target, GLsizei numAttachments,
+                                   const GLenum *attachments);
+
 }
 
 #endif // LIBANGLE_VALIDATION_ES2_H_

src/libANGLE/validationES3.cpp

@@ -1132,9 +1132,15 @@ bool ValidateES3RenderbufferStorageParameters(gl::Context *context, GLenum targe
     return true;
 }
 
-bool ValidateInvalidateFramebufferParameters(Context *context, GLenum target, GLsizei numAttachments,
-                                             const GLenum* attachments)
+bool ValidateInvalidateFramebuffer(Context *context, GLenum target, GLsizei numAttachments,
+                                   const GLenum *attachments)
 {
+    if (context->getClientVersion() < 3)
+    {
+        context->recordError(Error(GL_INVALID_OPERATION, "Operation only supported on ES 3.0 and above"));
+        return false;
+    }
+
     bool defaultFramebuffer = false;
 
     switch (target)
@@ -1147,56 +1153,11 @@ bool ValidateInvalidateFramebufferParameters(Context *context, GLenum target, GL
         defaultFramebuffer = context->getState().getReadFramebuffer()->id() == 0;
         break;
       default:
-          context->recordError(Error(GL_INVALID_ENUM));
-          return false;
-    }
-
-    for (int i = 0; i < numAttachments; ++i)
-    {
-        if (attachments[i] >= GL_COLOR_ATTACHMENT0 && attachments[i] <= GL_COLOR_ATTACHMENT15)
-        {
-            if (defaultFramebuffer)
-            {
-                context->recordError(Error(GL_INVALID_ENUM));
-                return false;
-            }
-
-            if (attachments[i] >= GL_COLOR_ATTACHMENT0 + context->getCaps().maxColorAttachments)
-            {
-                context->recordError(Error(GL_INVALID_OPERATION));
-                return false;
-            }
-        }
-        else
-        {
-            switch (attachments[i])
-            {
-              case GL_DEPTH_ATTACHMENT:
-              case GL_STENCIL_ATTACHMENT:
-              case GL_DEPTH_STENCIL_ATTACHMENT:
-                if (defaultFramebuffer)
-                {
-                    context->recordError(Error(GL_INVALID_ENUM));
-                    return false;
-                }
-                break;
-              case GL_COLOR:
-              case GL_DEPTH:
-              case GL_STENCIL:
-                if (!defaultFramebuffer)
-                {
-                    context->recordError(Error(GL_INVALID_ENUM));
-                    return false;
-                }
-                break;
-              default:
-                context->recordError(Error(GL_INVALID_ENUM));
-                return false;
-            }
-        }
+        context->recordError(Error(GL_INVALID_ENUM, "Invalid framebuffer target"));
+        return false;
     }
 
-    return true;
+    return ValidateDiscardFramebufferBase(context, target, numAttachments, attachments, defaultFramebuffer);
 }
 
 bool ValidateClearBuffer(Context *context)

src/libANGLE/validationES3.h

@@ -35,8 +35,8 @@ bool ValidES3ReadFormatType(Context *context, GLenum internalFormat, GLenum form
 bool ValidateES3RenderbufferStorageParameters(Context *context, GLenum target, GLsizei samples,
                                               GLenum internalformat, GLsizei width, GLsizei height);
 
-bool ValidateInvalidateFramebufferParameters(Context *context, GLenum target, GLsizei numAttachments,
-                                             const GLenum* attachments);
+bool ValidateInvalidateFramebuffer(Context *context, GLenum target, GLsizei numAttachments,
+                                   const GLenum *attachments);
 
 bool ValidateClearBuffer(Context *context);
 

src/libGLESv2/entry_points_egl.cpp

@@ -1162,6 +1162,7 @@ __eglMustCastToProperFunctionPointerType EGLAPIENTRY GetProcAddress(const char *
         { "glUnmapBufferOES", (__eglMustCastToProperFunctionPointerType)gl::UnmapBufferOES },
         { "glMapBufferRangeEXT", (__eglMustCastToProperFunctionPointerType)gl::MapBufferRangeEXT },
         { "glFlushMappedBufferRangeEXT", (__eglMustCastToProperFunctionPointerType)gl::FlushMappedBufferRangeEXT },
+        { "glDiscardFramebufferEXT", (__eglMustCastToProperFunctionPointerType)gl::DiscardFramebufferEXT },
         { "", NULL },
     };
 

src/libGLESv2/entry_points_gles_2_0_ext.cpp

@@ -684,6 +684,38 @@ void GL_APIENTRY BlitFramebufferANGLE(GLint srcX0, GLint srcY0, GLint srcX1, GLi
     }
 }
 
+void GL_APIENTRY DiscardFramebufferEXT(GLenum target, GLsizei numAttachments, const GLenum *attachments)
+{
+    EVENT("(GLenum target = 0x%X, GLsizei numAttachments = %d, attachments = 0x%0.8p)", target, numAttachments, attachments);
+
+    Context *context = GetValidGlobalContext();
+    if (context)
+    {
+        if (!context->getExtensions().discardFramebuffer)
+        {
+            context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
+            return;
+        }
+
+        if (!ValidateDiscardFramebufferEXT(context, target, numAttachments, attachments))
+        {
+            return;
+        }
+
+        Framebuffer *framebuffer = context->getState().getTargetFramebuffer(target);
+        ASSERT(framebuffer);
+
+        // The specification isn't clear what should be done when the framebuffer isn't complete.
+        // We leave it up to the framebuffer implementation to decide what to do.
+        Error error = framebuffer->discard(numAttachments, attachments);
+        if (error.isError())
+        {
+            context->recordError(error);
+            return;
+        }
+    }
+}
+
 void GL_APIENTRY TexImage3DOES(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLsizei depth,
                    GLint border, GLenum format, GLenum type, const GLvoid* pixels)
 {

src/libGLESv2/entry_points_gles_2_0_ext.h

@@ -22,6 +22,9 @@ ANGLE_EXPORT void GL_APIENTRY BlitFramebufferANGLE(GLint srcX0, GLint srcY0, GLi
 // GL_ANGLE_framebuffer_multisample
 ANGLE_EXPORT void GL_APIENTRY RenderbufferStorageMultisampleANGLE(GLenum target, GLsizei samples, GLenum internalformat, GLsizei width, GLsizei height);
 
+// GL_EXT_discard_framebuffer
+ANGLE_EXPORT void GL_APIENTRY DiscardFramebufferEXT(GLenum target, GLsizei numAttachments, const GLenum *attachments);
+
 // GL_NV_fence
 ANGLE_EXPORT void GL_APIENTRY DeleteFencesNV(GLsizei n, const GLuint* fences);
 ANGLE_EXPORT void GL_APIENTRY GenFencesNV(GLsizei n, GLuint* fences);

src/libGLESv2/entry_points_gles_3_0.cpp

@@ -3207,13 +3207,7 @@ void GL_APIENTRY InvalidateFramebuffer(GLenum target, GLsizei numAttachments, co
     Context *context = GetValidGlobalContext();
     if (context)
     {
-        if (context->getClientVersion() < 3)
-        {
-            context->recordError(Error(GL_INVALID_OPERATION));
-            return;
-        }
-
-        if (!ValidateInvalidateFramebufferParameters(context, target, numAttachments, attachments))
+        if (!ValidateInvalidateFramebuffer(context, target, numAttachments, attachments))
         {
             return;
         }
@@ -3242,13 +3236,7 @@ void GL_APIENTRY InvalidateSubFramebuffer(GLenum target, GLsizei numAttachments,
     Context *context = GetValidGlobalContext();
     if (context)
     {
-        if (context->getClientVersion() < 3)
-        {
-            context->recordError(Error(GL_INVALID_OPERATION));
-            return;
-        }
-
-        if (!ValidateInvalidateFramebufferParameters(context, target, numAttachments, attachments))
+        if (!ValidateInvalidateFramebuffer(context, target, numAttachments, attachments))
         {
             return;
         }

src/libGLESv2/libGLESv2.cpp

@@ -1256,6 +1256,11 @@ void GL_APIENTRY glRenderbufferStorageMultisampleANGLE(GLenum target, GLsizei sa
     return gl::RenderbufferStorageMultisampleANGLE(target, samples, internalformat, width, height);
 }
 
+void GL_APIENTRY glDiscardFramebufferEXT(GLenum target, GLsizei numAttachments, const GLenum *attachments)
+{
+    return gl::DiscardFramebufferEXT(target, numAttachments, attachments);
+}
+
 void GL_APIENTRY glDeleteFencesNV(GLsizei n, const GLuint* fences)
 {
     return gl::DeleteFencesNV(n, fences);

src/libGLESv2/libGLESv2.def

@@ -177,6 +177,7 @@ EXPORTS
     glGetBufferPointervOES          @287
     glMapBufferRangeEXT             @288
     glFlushMappedBufferRangeEXT     @289
+    glDiscardFramebufferEXT         @293
 
     ; GLES 3.0 Functions
     glReadBuffer                    @180

src/tests/angle_end2end_tests.gypi

@@ -21,6 +21,7 @@
             '<(angle_path)/src/tests/gl_tests/CompressedTextureTest.cpp',
             '<(angle_path)/src/tests/gl_tests/CubeMapTextureTest.cpp',
             '<(angle_path)/src/tests/gl_tests/DepthStencilFormatsTest.cpp',
+            '<(angle_path)/src/tests/gl_tests/DiscardFramebufferEXTTest.cpp',
             '<(angle_path)/src/tests/gl_tests/DrawBuffersTest.cpp',
             '<(angle_path)/src/tests/gl_tests/FenceSyncTests.cpp',
             '<(angle_path)/src/tests/gl_tests/FramebufferFormatsTest.cpp',

src/tests/gl_tests/DiscardFramebufferEXTTest.cpp

+//
+// Copyright 2015 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.
+//
+
+#include "test_utils/ANGLETest.h"
+
+using namespace angle;
+
+class DiscardFramebufferEXTTest : public ANGLETest
+{
+protected:
+    DiscardFramebufferEXTTest()
+    {
+        setWindowWidth(256);
+        setWindowHeight(256);
+        setConfigRedBits(8);
+        setConfigGreenBits(8);
+        setConfigBlueBits(8);
+        setConfigAlphaBits(8);
+        setConfigDepthBits(24);
+        setConfigStencilBits(8);
+    }
+};
+
+TEST_P(DiscardFramebufferEXTTest, ExtensionEnabled)
+{
+    EGLPlatformParameters platform = GetParam().mEGLPlatformParameters;
+
+    if (platform.renderer == EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE)
+    {
+        // EXPECT_TRUE(extensionEnabled("EXT_discard_framebuffer"));
+
+        // EXT_discard_framebuffer is disabled in D3D11 ANGLE due to Chromium BUG:497445
+        // Enabling this extension (even as a no-op) causes WebGL video failures in Chromium
+        // Once this bug is fixed, we can reenable the extension.
+        EXPECT_FALSE(extensionEnabled("EXT_discard_framebuffer"));
+    }
+    else
+    {
+        // Other platforms don't currently implement this extension
+        EXPECT_FALSE(extensionEnabled("EXT_discard_framebuffer"));
+    }
+}
+
+TEST_P(DiscardFramebufferEXTTest, DefaultFramebuffer)
+{
+    if (!extensionEnabled("EXT_discard_framebuffer"))
+    {
+        std::cout << "Test skipped because EXT_discard_framebuffer is not available." << std::endl;
+        return;
+    }
+
+    // These should succeed on the default framebuffer
+    const GLenum discards1[] = { GL_COLOR_EXT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards1);
+    EXPECT_GL_NO_ERROR();
+
+    const GLenum discards2[] = { GL_DEPTH_EXT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards2);
+    EXPECT_GL_NO_ERROR();
+
+    const GLenum discards3[] = { GL_STENCIL_EXT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards3);
+    EXPECT_GL_NO_ERROR();
+
+    const GLenum discards4[] = { GL_STENCIL_EXT, GL_COLOR_EXT, GL_DEPTH_EXT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 3, discards4);
+    EXPECT_GL_NO_ERROR();
+
+    // These should fail on the default framebuffer
+    const GLenum discards5[] = { GL_COLOR_ATTACHMENT0 };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards5);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+
+    const GLenum discards6[] = { GL_DEPTH_ATTACHMENT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards6);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+
+    const GLenum discards7[] = { GL_STENCIL_ATTACHMENT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards7);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+}
+
+TEST_P(DiscardFramebufferEXTTest, NonDefaultFramebuffer)
+{
+    if (!extensionEnabled("EXT_discard_framebuffer"))
+    {
+        std::cout << "Test skipped because EXT_discard_framebuffer is not available." << std::endl;
+        return;
+    }
+
+    GLuint tex2D;
+    GLuint framebuffer;
+
+    // Create a basic off-screen framebuffer
+    // Don't create a depth/stencil texture, to ensure that also works correctly
+    glGenTextures(1, &tex2D);
+    glGenFramebuffers(1, &framebuffer);
+    glBindTexture(GL_TEXTURE_2D, tex2D);
+    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, getWindowWidth(), getWindowHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex2D, 0);
+    ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), GL_FRAMEBUFFER_COMPLETE);
+
+    // These should fail on the non-default framebuffer
+    const GLenum discards1[] = { GL_COLOR_EXT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards1);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+
+    const GLenum discards2[] = { GL_DEPTH_EXT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards2);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+
+    const GLenum discards3[] = { GL_STENCIL_EXT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards3);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+
+    const GLenum discards4[] = { GL_STENCIL_EXT, GL_COLOR_EXT, GL_DEPTH_EXT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 3, discards4);
+    EXPECT_GL_ERROR(GL_INVALID_ENUM);
+
+    // These should succeed on the non-default framebuffer
+    const GLenum discards5[] = { GL_COLOR_ATTACHMENT0 };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards5);
+    EXPECT_GL_NO_ERROR();
+
+    const GLenum discards6[] = { GL_DEPTH_ATTACHMENT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards6);
+    EXPECT_GL_NO_ERROR();
+
+    const GLenum discards7[] = { GL_STENCIL_ATTACHMENT };
+    glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards7);
+    EXPECT_GL_NO_ERROR();
+}
+
+// Use this to select which configurations (e.g. which renderer, which GLES major version) these tests should be run against.
+ANGLE_INSTANTIATE_TEST(DiscardFramebufferEXTTest, ES2_D3D9(), ES2_D3D11(), ES2_D3D11_FL9_3(), ES2_OPENGL(), ES3_OPENGL());