Bug 1016086 - Part 2: Save/restore attribute state in blit helper (r=Bas)

gfx/gl/GLBlitTextureImageHelper.cpp

@@ -146,26 +146,14 @@ GLBlitTextureImageHelper::BlitTextureImage(TextureImage *aSrc, const nsIntRect&
 
             ScopedBindTextureUnit autoTexUnit(mGL, LOCAL_GL_TEXTURE0);
             ScopedBindTexture autoTex(mGL, aSrc->GetTextureID());
-
-            mGL->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, 0);
-
-            mGL->fVertexAttribPointer(0, 2, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, rects.vertCoords().Elements());
-            mGL->fVertexAttribPointer(1, 2, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, rects.texCoords().Elements());
-
-            mGL->fEnableVertexAttribArray(0);
-            mGL->fEnableVertexAttribArray(1);
+            ScopedVertexAttribPointer autoAttrib0(mGL, 0, 2, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, 0, rects.vertCoords().Elements());
+            ScopedVertexAttribPointer autoAttrib1(mGL, 1, 2, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, 0, rects.texCoords().Elements());
 
             mGL->fDrawArrays(LOCAL_GL_TRIANGLES, 0, rects.elements());
 
-            mGL->fDisableVertexAttribArray(0);
-            mGL->fDisableVertexAttribArray(1);
-
         } while (aSrc->NextTile());
     } while (aDst->NextTile());
 
-    mGL->fVertexAttribPointer(0, 2, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, nullptr);
-    mGL->fVertexAttribPointer(1, 2, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, nullptr);
-
     // unbind the previous texture from the framebuffer
     SetBlitFramebufferForDestTexture(0);
 

gfx/gl/ScopedGLHelpers.cpp

@@ -330,5 +330,76 @@ void ScopedScissorRect::UnwrapImpl()
                 mSavedScissorRect[3]);
 }
 
+/* ScopedVertexAttribPointer **************************************************/
+
+ScopedVertexAttribPointer::ScopedVertexAttribPointer(GLContext* aGL,
+                                                     GLuint index,
+                                                     GLint size,
+                                                     GLenum type,
+                                                     realGLboolean normalized,
+                                                     GLsizei stride,
+                                                     GLuint buffer,
+                                                     const GLvoid* pointer)
+    : ScopedGLWrapper<ScopedVertexAttribPointer>(aGL)
+{
+    WrapImpl(index);
+    mGL->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, buffer);
+    mGL->fVertexAttribPointer(index, size, type, normalized, stride, pointer);
+    mGL->fEnableVertexAttribArray(index);
+}
+
+ScopedVertexAttribPointer::ScopedVertexAttribPointer(GLContext* aGL,
+                                                     GLuint index)
+    : ScopedGLWrapper<ScopedVertexAttribPointer>(aGL)
+{
+    WrapImpl(index);
+}
+
+void
+ScopedVertexAttribPointer::WrapImpl(GLuint index)
+{
+    mAttribIndex = index;
+
+    /*
+     * mGL->fGetVertexAttribiv takes:
+     *  VERTEX_ATTRIB_ARRAY_ENABLED
+     *  VERTEX_ATTRIB_ARRAY_SIZE,
+     *  VERTEX_ATTRIB_ARRAY_STRIDE,
+     *  VERTEX_ATTRIB_ARRAY_TYPE,
+     *  VERTEX_ATTRIB_ARRAY_NORMALIZED,
+     *  VERTEX_ATTRIB_ARRAY_BUFFER_BINDING,
+     *  CURRENT_VERTEX_ATTRIB
+     *
+     * CURRENT_VERTEX_ATTRIB is vertex shader state. \o/
+     * Others appear to be vertex array state,
+     * or alternatively in the internal vertex array state
+     * for a buffer object.
+    */
+
+    mGL->fGetVertexAttribiv(mAttribIndex, LOCAL_GL_VERTEX_ATTRIB_ARRAY_ENABLED, &mAttribEnabled);
+    mGL->fGetVertexAttribiv(mAttribIndex, LOCAL_GL_VERTEX_ATTRIB_ARRAY_SIZE, &mAttribSize);
+    mGL->fGetVertexAttribiv(mAttribIndex, LOCAL_GL_VERTEX_ATTRIB_ARRAY_STRIDE, &mAttribStride);
+    mGL->fGetVertexAttribiv(mAttribIndex, LOCAL_GL_VERTEX_ATTRIB_ARRAY_TYPE, &mAttribType);
+    mGL->fGetVertexAttribiv(mAttribIndex, LOCAL_GL_VERTEX_ATTRIB_ARRAY_NORMALIZED, &mAttribNormalized);
+    mGL->fGetVertexAttribiv(mAttribIndex, LOCAL_GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING, &mAttribBufferBinding);
+    mGL->fGetVertexAttribPointerv(mAttribIndex, LOCAL_GL_VERTEX_ATTRIB_ARRAY_POINTER, &mAttribPointer);
+
+    // Note that uniform values are program state, so we don't need to rebind those.
+
+    mGL->GetUIntegerv(LOCAL_GL_ARRAY_BUFFER_BINDING, &mBoundBuffer);
+}
+
+void
+ScopedVertexAttribPointer::UnwrapImpl()
+{
+    mGL->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, mAttribBufferBinding);
+    mGL->fVertexAttribPointer(mAttribIndex, mAttribSize, mAttribType, mAttribNormalized, mAttribStride, mAttribPointer);
+    if (mAttribEnabled)
+        mGL->fEnableVertexAttribArray(mAttribIndex);
+    else
+        mGL->fDisableVertexAttribArray(mAttribIndex);
+    mGL->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, mBoundBuffer);
+}
+
 } /* namespace gl */
 } /* namespace mozilla */

gfx/gl/ScopedGLHelpers.h

@@ -277,6 +277,32 @@ protected:
     void UnwrapImpl();
 };
 
+struct ScopedVertexAttribPointer
+    : public ScopedGLWrapper<ScopedVertexAttribPointer>
+{
+    friend struct ScopedGLWrapper<ScopedVertexAttribPointer>;
+
+protected:
+    GLuint mAttribIndex;
+    GLint mAttribEnabled;
+    GLint mAttribSize;
+    GLint mAttribStride;
+    GLint mAttribType;
+    GLint mAttribNormalized;
+    GLint mAttribBufferBinding;
+    void* mAttribPointer;
+    GLuint mBoundBuffer;
+
+public:
+    ScopedVertexAttribPointer(GLContext* aGL, GLuint index, GLint size, GLenum type, realGLboolean normalized,
+                              GLsizei stride, GLuint buffer, const GLvoid* pointer);
+    explicit ScopedVertexAttribPointer(GLContext* aGL, GLuint index);
+
+protected:
+    void WrapImpl(GLuint index);
+    void UnwrapImpl();
+};
+
 } /* namespace gl */
 } /* namespace mozilla */