source files: xgtm.[ch], term/*.trm, gtplot.h
(GT-SWAP-BUFFERS) (SEND <gtm:terminal> :SWAP-BUFFERS)
In double-buffered mode, this call swaps display buffers, making the just-constructed image visible to the user, and freeing the buffer the user was just looking at for program use. Most 3D applications will run in double buffered mode, and will call GT-SWAP-BUFFERS each time they finish constructing an image.
Note that this call waits until the start of the next video frame before actually swapping, so as to synchronize with the display. This can cost you up to 1/60th of a second. This is not normally a problem, and in fact normally serves to make the graphics display run at a constant rate independent of computational load, until the display becomes too complex to compute in one frametime.