Can I have some advice on the following points?
1. Is the only way to execute OpenGl commands (glColor3f) by setting a call back function when setting the window to V3d_View?
2. If you want to control the drawing (to the window), is the best way to create a frame buffer object and render that yourself?
Thank you for your advice, it would be great to have answers to these because it would open opportunities such as transparent UI, custom rendering.