Correct the alpha logic in glProgram

the alpha cover should not be necessary

Change-Id: Ieef8282d431d73ff8d5520a1bc4e3b6262721e9b
Tests: Android UI correctly rendered
Tracked-On: None
Signed-off-by: Lin Johnson <[email protected]>

Author: js0701

common/compositor/gl/glprogram.cpp

@@ -105,8 +105,6 @@ static std::string GenerateFragmentShader(int layer_count) {
                          << "  vec3 multRgb;\n"
                          << "  float tempAlpha;\n";
   for (int i = 0; i < layer_count; ++i) {
-    if (i > 0)
-      fragment_shader_stream << "  if (alphaCover > 0.5/255.0) {\n";
     // clang-format off
     fragment_shader_stream << "  texSample = texture2D(uLayerTexture" << i
                            << ",\n"
@@ -120,14 +118,10 @@ static std::string GenerateFragmentShader(int layer_count) {
                            << "            max(tempAlpha, uLayerPremult[" << i
                            << "]);\n"
                            << "  color += multRgb * uLayerAlpha[" << i
-                           << "] * alphaCover;\n"
-                           << "  alphaCover *= 1.0 - texSample.a * uLayerAlpha["
-                           << i << "];\n";
+                           << "] ;\n"
     // clang-format on
   }
-  for (int i = 0; i < layer_count - 1; ++i)
-    fragment_shader_stream << "  }\n";
-  fragment_shader_stream << "  oFragColor = vec4(color, 1.0 - alphaCover);\n"
+  fragment_shader_stream << "  oFragColor = vec4(color, 1.0);\n"
                          << "}\n";
   return fragment_shader_stream.str();
 }