sparkler: enable rudimentary threaded rendering

This moves most of the particle system maintenance into the serially
executed sparkler_prepare_frame(), divides the frame into ncpus
fragments, and leaves the draw to occur concurrently.

The drawing must still currently process all particles and simply skips
drawing those falling outside the fragment.

Moving more of the computation out of prepare_frame() and into
render_fragment() is left for future improvements, as it's a bit
complex to do gainfully.

0 files changed, 0 insertions, 0 deletions