Previously, Pteropus would only redraw when the window was resized, but
it would continuously poll for events, keeping a CPU core at 100% even
when not doing anything.
It now automatically queues a new RedrawRequested event after each draw
finishes. The view() call will also limit the frame rate to the video
refresh rate and block when there are more than three frames queued up,
so we're not busywaiting any more.
Reconfigure the pipeline to draw an unlit (solid colour silhouette) cube
when a DEM is loaded. The fragment shader of this cube will be what
raytraces the DEM.
Matthew Gordon