Prevent opaque windows from making framebuffer translucent
To keep the code readable now that we have four different texenv
configurations, this change separates the decisions about what
configuration to use from the GL calls to set up the configuration.
Bug: 8963244
Change-Id: Ia07a306a7809ba8f93493d0160ccbd509e948581
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index c15dfd5..ee69222 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -559,31 +559,88 @@
clearWithOpenGL(hw, clip, 0,0,0,0);
}
+static void setupOpenGL10(bool premultipliedAlpha, bool opaque, int alpha) {
+ // OpenGL ES 1.0 doesn't support texture combiners.
+ // This path doesn't properly handle opaque layers that have non-opaque
+ // alpha values. The alpha channel will be copied into the framebuffer or
+ // screenshot, so if the framebuffer or screenshot is blended on top of
+ // something else, whatever is below the window will incorrectly show
+ // through.
+ if (CC_UNLIKELY(alpha < 0xFF)) {
+ GLfloat floatAlpha = alpha * (1.0f / 255.0f);
+ if (premultipliedAlpha) {
+ glColor4f(floatAlpha, floatAlpha, floatAlpha, floatAlpha);
+ } else {
+ glColor4f(1.0f, 1.0f, 1.0f, floatAlpha);
+ }
+ glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
+ } else {
+ glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
+ }
+}
+
+static void setupOpenGL11(bool premultipliedAlpha, bool opaque, int alpha) {
+ GLenum combineRGB;
+ GLenum combineAlpha;
+ GLenum src0Alpha;
+ GLfloat envColor[4];
+
+ if (CC_UNLIKELY(alpha < 0xFF)) {
+ // Cv = premultiplied ? Cs*alpha : Cs
+ // Av = !opaque ? alpha*As : 1.0
+ combineRGB = premultipliedAlpha ? GL_MODULATE : GL_REPLACE;
+ combineAlpha = !opaque ? GL_MODULATE : GL_REPLACE;
+ src0Alpha = GL_CONSTANT;
+ envColor[0] = alpha * (1.0f / 255.0f);
+ } else {
+ // Cv = Cs
+ // Av = opaque ? 1.0 : As
+ combineRGB = GL_REPLACE;
+ combineAlpha = GL_REPLACE;
+ src0Alpha = opaque ? GL_CONSTANT : GL_TEXTURE;
+ envColor[0] = 1.0f;
+ }
+
+ glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
+ glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB, combineRGB);
+ glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_RGB, GL_TEXTURE);
+ glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
+ if (combineRGB == GL_MODULATE) {
+ glTexEnvi(GL_TEXTURE_ENV, GL_SRC1_RGB, GL_CONSTANT);
+ glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_RGB, GL_SRC_COLOR);
+ }
+ glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA, combineAlpha);
+ glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_ALPHA, src0Alpha);
+ glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
+ if (combineAlpha == GL_MODULATE) {
+ glTexEnvi(GL_TEXTURE_ENV, GL_SRC1_ALPHA, GL_TEXTURE);
+ glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_ALPHA, GL_SRC_ALPHA);
+ }
+ if (combineRGB == GL_MODULATE || src0Alpha == GL_CONSTANT) {
+ envColor[1] = envColor[0];
+ envColor[2] = envColor[0];
+ envColor[3] = envColor[0];
+ glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, envColor);
+ }
+}
+
void Layer::drawWithOpenGL(
const sp<const DisplayDevice>& hw, const Region& clip) const {
const uint32_t fbHeight = hw->getHeight();
const State& s(drawingState());
- GLenum src = mPremultipliedAlpha ? GL_ONE : GL_SRC_ALPHA;
- if (CC_UNLIKELY(s.alpha < 0xFF)) {
- const GLfloat alpha = s.alpha * (1.0f/255.0f);
- if (mPremultipliedAlpha) {
- glColor4f(alpha, alpha, alpha, alpha);
- } else {
- glColor4f(1, 1, 1, alpha);
- }
- glEnable(GL_BLEND);
- glBlendFunc(src, GL_ONE_MINUS_SRC_ALPHA);
- glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
+ if (mFlinger->getGlesVersion() == GLES_VERSION_1_0) {
+ setupOpenGL10(mPremultipliedAlpha, isOpaque(), s.alpha);
} else {
- glColor4f(1, 1, 1, 1);
- glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
- if (!isOpaque()) {
- glEnable(GL_BLEND);
- glBlendFunc(src, GL_ONE_MINUS_SRC_ALPHA);
- } else {
- glDisable(GL_BLEND);
- }
+ setupOpenGL11(mPremultipliedAlpha, isOpaque(), s.alpha);
+ }
+
+ if (s.alpha < 0xFF || !isOpaque()) {
+ glEnable(GL_BLEND);
+ glBlendFunc(mPremultipliedAlpha ? GL_ONE : GL_SRC_ALPHA,
+ GL_ONE_MINUS_SRC_ALPHA);
+ } else {
+ glDisable(GL_BLEND);
}
LayerMesh mesh;