Copying data from one texture to another - opengl

Question

I'm rendering my camera preview in android on a SurfaceTexure. This SurfaceTexture is bound to target GL_TEXTURE_EXTERNAL_OES. I want to copy the texture data from this SurfaceTexture object to my custom OpenGL texture which is bound to GL_TEXTURE_2D.

My onFrameAvailable callback is as follows :

@Override
public void onFrameAvailable(final SurfaceTexture surfaceTexture) {
    glView.queueEvent(new Runnable() {
        @Override
        public void run() {
            surfaceTexture.updateTexImage();
            //TODO: Copy this texture to the custom texture
        }
    });
}

I have the custom texture object created already.

Can anyone help me with the copying part ?

Answer 1

The usual approach is to bind the texture at a color attachment to an FBO, select that FBO as active and use glCopyTexImage to copy from the FBO into the destination texture.