til: support multi-pass rendering

Modules can now use the til_module_t.finish_frame() return value
to trigger re-rendering by returning 1, returning 0 finishes the
frame.

A smattering of til_module_t.finish_frame() implementations were
largely mechanically updated to match this change by returning 0,
since nothing actually uses multi-pass rendering yet.

The impetus for this is experimenting with the flow module doing
two passes of threaded rendering per frame.  A first pass to
sample the flow field and update the elements, per-cpu, but
drawing nothing.  Then a second pass to render the elements in a
tiled manner.

0 files changed, 0 insertions, 0 deletions