Forum Discussion
OpenGL : retrieving the framebuffer of an attached window
Hi, As I mentioned in the midst of another topic, I would like to know if and how it is possible to retrieve the framebuffer's content currently displayed in the Rift at every frame (e.g. using glR...
"lamour42" wrote:"jherico" wrote:
With OpenGL, Oculus is more limited in terms of when they can grab the screen image and transfer it to the display, leading to the limitations we see.
That is certainly true for SDK rendered mode. But for client rendering there is no 'screen grabbing', right? The original post was about client rendering.
No, the issue of getting the pixels from GPU memory to the Rift display is completely orthogonal to whether you're doing SDK distortion or client distortion (I dislike using the term 'client rendering' since all apps do rendering of some sort on the client).
Essentially, when you call ovrHmd_AttachToWindow you're causing the Oculus runtime (not the SDK) to do something that changes the way the swap buffers call works, forcing it to the sync to the Rift refresh rate, rather than the refresh rate of the screen on which the proxy window is visible, and causing the pixels to appear there (as well as on the proxy window, though possibly only after additional latency). This is the case whether you're calling swap buffers yourself (client distortion) or allow the SDK to do so (SDK distortion).