allows manuall processing of frames. timediff is in milliseconds, if not passed we will compute from the last time this function was called. this will run all internal thinks except the lua think. You should never start this unless you want to do frame processing from this time on for the rest of the runtime. Ideally this function is part of a loop which you start right in your initialisation script. Using this kind of setup will not return the same results as the automatic think and maxfps will show no effect. For one the performance graphs will not measure the luathink correctly, as well as
ode. Also the order of the thinkcycle is slightly different. Be aware that you must run swapbuffers yourself to see the result of rendering. A good order of your think would be: processframe,your changes, swapbuffers. This would be close to the internal order, just that swapbuffers is called differently, but still would allow some cpu/gpu parallelism. Internally the order of a think in automatic mode is in one frame:
render, luathink,
sound, actors/
scenenodes,swapbuffers.
Compared to the manual mode of this function:
sound,actors/
scenenodes,
render