SF: Skip render-to-texture for color transforms
In cases where SurfaceFlinger is applying a color matrix (usually for
accessibility features), we previously would perform a render-to-
texture for the initial composition, and then apply the matrix during
a copy to the framebuffer. This changes that behavior to just apply the
matrix during composition without a render-to-texture pass.
This may result in a perceived change of the image in cases with alpha
blending, since the blending is performed at a different stage of the
pipeline and the system effectively performs non-linear blends.
However, neither this nor the prior render-to-texture pass is strictly
correct in that regard, and this approach is less error-prone and
likely faster.
Change-Id: I2110ff0374f61d76df7b087dde8a1ed98990440c
diff --git a/services/surfaceflinger/RenderEngine/GLES20RenderEngine.cpp b/services/surfaceflinger/RenderEngine/GLES20RenderEngine.cpp
index 8712c9a..1fabaf5 100644
--- a/services/surfaceflinger/RenderEngine/GLES20RenderEngine.cpp
+++ b/services/surfaceflinger/RenderEngine/GLES20RenderEngine.cpp
@@ -169,6 +169,12 @@
mState.setTexture(texture);
}
+mat4 GLES20RenderEngine::setupColorTransform(const mat4& colorTransform) {
+ mat4 oldTransform = mState.getColorMatrix();
+ mState.setColorMatrix(colorTransform);
+ return oldTransform;
+}
+
void GLES20RenderEngine::disableTexturing() {
mState.disableTexture();
}
@@ -237,78 +243,6 @@
}
}
-void GLES20RenderEngine::beginGroup(const mat4& colorTransform) {
-
- GLuint tname, name;
- // create the texture
- glGenTextures(1, &tname);
- glBindTexture(GL_TEXTURE_2D, tname);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
- glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, mVpWidth, mVpHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
-
- // create a Framebuffer Object to render into
- glGenFramebuffers(1, &name);
- glBindFramebuffer(GL_FRAMEBUFFER, name);
- glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tname, 0);
-
- Group group;
- group.texture = tname;
- group.fbo = name;
- group.width = mVpWidth;
- group.height = mVpHeight;
- group.colorTransform = colorTransform;
-
- mGroupStack.push(group);
-}
-
-void GLES20RenderEngine::endGroup() {
-
- const Group group(mGroupStack.top());
- mGroupStack.pop();
-
- // activate the previous render target
- GLuint fbo = 0;
- if (!mGroupStack.isEmpty()) {
- fbo = mGroupStack.top().fbo;
- }
- glBindFramebuffer(GL_FRAMEBUFFER, fbo);
-
- // set our state
- Texture texture(Texture::TEXTURE_2D, group.texture);
- texture.setDimensions(group.width, group.height);
- glBindTexture(GL_TEXTURE_2D, group.texture);
-
- mState.setPlaneAlpha(1.0f);
- mState.setPremultipliedAlpha(true);
- mState.setOpaque(false);
- mState.setTexture(texture);
- mState.setColorMatrix(group.colorTransform);
- glDisable(GL_BLEND);
-
- Mesh mesh(Mesh::TRIANGLE_FAN, 4, 2, 2);
- Mesh::VertexArray<vec2> position(mesh.getPositionArray<vec2>());
- Mesh::VertexArray<vec2> texCoord(mesh.getTexCoordArray<vec2>());
- position[0] = vec2(0, 0);
- position[1] = vec2(group.width, 0);
- position[2] = vec2(group.width, group.height);
- position[3] = vec2(0, group.height);
- texCoord[0] = vec2(0, 0);
- texCoord[1] = vec2(1, 0);
- texCoord[2] = vec2(1, 1);
- texCoord[3] = vec2(0, 1);
- drawMesh(mesh);
-
- // reset color matrix
- mState.setColorMatrix(mat4());
-
- // free our fbo and texture
- glDeleteFramebuffers(1, &group.fbo);
- glDeleteTextures(1, &group.texture);
-}
-
void GLES20RenderEngine::dump(String8& result) {
RenderEngine::dump(result);
}