Use matching internal and external formats for RGBA8 images.

Change-Id: I056e1a4c7ace83207bed85ce28aca187d72adc6f
Reviewed-on: https://swiftshader-review.googlesource.com/2757
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
diff --git a/src/OpenGL/libGLESv2/Renderbuffer.cpp b/src/OpenGL/libGLESv2/Renderbuffer.cpp
index d250869..b35405d 100644
--- a/src/OpenGL/libGLESv2/Renderbuffer.cpp
+++ b/src/OpenGL/libGLESv2/Renderbuffer.cpp
@@ -386,7 +386,7 @@
 	mWidth = 0;
 	mHeight = 0;
 	format = GL_RGBA4;
-	internalFormat = sw::FORMAT_A8R8G8B8;
+	internalFormat = sw::FORMAT_A8B8G8R8;
 	mSamples = 0;
 }