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.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/modules/checkers/checkers.c b/src/modules/checkers/checkers.c
index 360d553..43f4e1f 100644
--- a/src/modules/checkers/checkers.c
+++ b/src/modules/checkers/checkers.c
@@ -440,7 +440,7 @@ static void checkers_render_fragment(til_module_context_t *context, til_stream_t
 }
 
 
-static void checkers_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr)
+static int checkers_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr)
 {
 	checkers_context_t	*ctxt = (checkers_context_t *)context;
 
@@ -487,6 +487,8 @@ static void checkers_finish_frame(til_module_context_t *context, til_stream_t *s
 #endif
 		}
 	}
+
+	return 0;
 }