Native bindings to the NV_robustness_video_memory_purge extension.

This extension allows applications to be notified when video memory has been purged.

The NVIDIA OpenGL driver architecture on Linux has a limitation: resources located in video memory are not persistent across certain events. VT switches, suspend/resume events, and mode switching events may erase the contents of video memory. Any resource that is located exclusively in video memory, such as framebuffer objects (FBOs), will be lost. As the OpenGL specification makes no mention of events where the video memory is allowed to be cleared, the driver attempts to hide this fact from the application, but cannot do it for all resources.

This extension provides a way for applications to discover when video memory content has been lost, so that the application can re-populate the video memory content as necessary.

This extension will have a limited lifespan, as planned architectural evolutions in the NVIDIA Linux driver stack will allow video memory to be persistent. Any driver that exposes this extension is a driver that considers video memory to be volatile. Once the driver stack has been improved, the extension will no longer be exposed.