I want to display a plane in 3D on top of a rendered 3D image. I have dobb buffers. I tryed this:
- Render the 3D image to GL_BACK
- Draw to GL_FRONT a plane, it displays OK
- Swapbuffers to erase the plane and get a new copy of the 3D
- Draw a plane at a new position in GL_FRONT and it works.
It works, but only if the plane is not in the same position in 3D - otherwise nothing is displayed unless i re-render the 3D in GL_BACK.
I’m sure it’s simple, but i can’t figur it out based on “OpenGL Programming Guide”.
Can anybody give me a hint?