I’m trying to render (fullscreen, CGL) to two displays from a single GPU, as in Figure 1.7.
When I capture all displays and go fullscreen, only the main display is rendered to. I believe the problem is that the pixel format attribute corresponding to kCGLPFADisplayMask is CGDisplayIDToOpenGLDisplayMask( kCGDirectMainDisplay ), which ignores other displays.
I was hoping that since I want one virtual screen, I could use a single context to render it to both physical displays.
Do I have to create a separate context for each physical display? If not, could someone point me in the right direction?
I believe you need two full-screen contexts, one for each display, or one windowed context (which might nevertheless cover the full screen) crossing both.