`glCopyTexImage2D` using `GL_RGB8_OES` extension on OpenGL ES 2.0 iPhone 6.1

Question

When I call

glCopyTexImage2D( GL_TEXTURE_2D, 0, GL_RGB8_OES, 0, 0, w, h, 0 );

I get GLERROR 1281 GL_INVALID_VALUE . If I use

glCopyTexImage2D( GL_TEXTURE_2D, 0, GL_RGB, 0, 0, w, h, 0 );

It works fine.

It seems GL_RGB8_OES is unsupported for glCopyTexImage2D ! Such a glaring omission, I find that hard to believe. How can I rescue the alpha channel?

Answer 1

Have you tried using GL_RGBA ?

http://www.opengl.org/sdk/docs/man/xhtml/glCopyTexImage2D.xml