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.

10 files changed, 44 insertions, 28 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;
 }
 
 
diff --git a/src/modules/drizzle/drizzle.c b/src/modules/drizzle/drizzle.c
index 0614632..b261448 100644
--- a/src/modules/drizzle/drizzle.c
+++ b/src/modules/drizzle/drizzle.c
@@ -347,12 +347,14 @@ static void drizzle_render_fragment(til_module_context_t *context, til_stream_t
 }
 
 
-static void drizzle_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
+static int drizzle_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
 {
 	drizzle_context_t	*ctxt = (drizzle_context_t *)context;
 
 	if (ctxt->snapshot)
 		ctxt->snapshot = til_fb_fragment_reclaim(ctxt->snapshot);
+
+	return 0;
 }
 
 
diff --git a/src/modules/mixer/mixer.c b/src/modules/mixer/mixer.c
index 5ec54ed..d8c1326 100644
--- a/src/modules/mixer/mixer.c
+++ b/src/modules/mixer/mixer.c
@@ -271,7 +271,7 @@ static void mixer_render_fragment(til_module_context_t *context, til_stream_t *s
 }
 
 
-static void mixer_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
+static int mixer_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
 {
 	mixer_context_t	*ctxt = (mixer_context_t *)context;
 
@@ -281,6 +281,8 @@ static void mixer_finish_frame(til_module_context_t *context, til_stream_t *stre
 
 		ctxt->snapshots[i] = til_fb_fragment_reclaim(ctxt->snapshots[i]);
 	}
+
+	return 0;
 }
 
 
diff --git a/src/modules/ray/ray.c b/src/modules/ray/ray.c
index ea44491..4c4bdd0 100644
--- a/src/modules/ray/ray.c
+++ b/src/modules/ray/ray.c
@@ -187,11 +187,13 @@ static void ray_render_fragment(til_module_context_t *context, til_stream_t *str
 }
 
 
-static void ray_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr)
+static int ray_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr)
 {
 	ray_context_t	*ctxt = (ray_context_t *)context;
 
 	ray_render_free(ctxt->render);
+
+	return 0;
 }
 
 
diff --git a/src/modules/rtv/rtv.c b/src/modules/rtv/rtv.c
index 95418aa..0c2ab73 100644
--- a/src/modules/rtv/rtv.c
+++ b/src/modules/rtv/rtv.c
@@ -70,7 +70,7 @@ static void setup_next_channel(rtv_context_t *ctxt, unsigned ticks);
 static til_module_context_t * rtv_create_context(const til_module_t *module, til_stream_t *stream, unsigned seed, unsigned ticks, unsigned n_cpus, til_setup_t *setup);
 static void rtv_destroy_context(til_module_context_t *context);
 static void rtv_render_fragment(til_module_context_t *context, til_stream_t *stream, unsigned ticks, unsigned cpu, til_fb_fragment_t **fragment_ptr);
-static void rtv_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr);
+static int rtv_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr);
 static int rtv_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup);
 
 static til_module_t	rtv_none_module = {};
@@ -330,26 +330,27 @@ static void rtv_render_fragment(til_module_context_t *context, til_stream_t *str
 }
 
 
-static void rtv_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr)
+static int rtv_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr)
 {
 	rtv_context_t		*ctxt = (rtv_context_t *)context;
 	til_fb_fragment_t	*fragment = *fragment_ptr;
 
-	if (!ctxt->caption)
-		return;
-
-	txt_render_fragment(ctxt->caption, fragment, 0x00000000,
-			    1, fragment->frame_height + 1,
-			    (txt_align_t){
+	if (ctxt->caption) {
+		txt_render_fragment(ctxt->caption, fragment, 0x00000000,
+				    1, fragment->frame_height + 1,
+				    (txt_align_t){
+						.horiz = TXT_HALIGN_LEFT,
+						.vert = TXT_VALIGN_BOTTOM
+				    });
+		txt_render_fragment(ctxt->caption, fragment, 0xffffffff,
+				    0, fragment->frame_height,
+				    (txt_align_t){
 					.horiz = TXT_HALIGN_LEFT,
 					.vert = TXT_VALIGN_BOTTOM
-			    });
-	txt_render_fragment(ctxt->caption, fragment, 0xffffffff,
-			    0, fragment->frame_height,
-			    (txt_align_t){
-				.horiz = TXT_HALIGN_LEFT,
-				.vert = TXT_VALIGN_BOTTOM
-			    });
+				    });
+	}
+
+	return 0;
 }
 
 
diff --git a/src/modules/shapes/shapes.c b/src/modules/shapes/shapes.c
index 977d9a7..099c050 100644
--- a/src/modules/shapes/shapes.c
+++ b/src/modules/shapes/shapes.c
@@ -548,7 +548,7 @@ static void shapes_render_fragment(til_module_context_t *context, til_stream_t *
 }
 
 
-static void shapes_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
+static int shapes_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
 {
 	shapes_context_t	*ctxt = (shapes_context_t *)context;
 	til_fb_fragment_t	*fragment = *fragment_ptr;
@@ -571,6 +571,8 @@ static void shapes_finish_frame(til_module_context_t *context, til_stream_t *str
 	if (fragment->width == fragment->frame_width &&
 	    fragment->height == fragment->frame_height)
 		ctxt->radcache->initialized = 1;
+
+	return 0;
 }
 
 
diff --git a/src/modules/strobe/strobe.c b/src/modules/strobe/strobe.c
index 9e7024c..3d354e8 100644
--- a/src/modules/strobe/strobe.c
+++ b/src/modules/strobe/strobe.c
@@ -129,15 +129,16 @@ static void strobe_render_fragment(til_module_context_t *context, til_stream_t *
 }
 
 
-static void strobe_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
+static int strobe_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
 {
 	strobe_context_t	*ctxt = (strobe_context_t *)context;
 
-	if (!ctxt->flash)
-		return;
+	if (ctxt->flash) {
+		ctxt->flash = 0;
+		ctxt->last_flash_ticks = ticks;
+	}
 
-	ctxt->flash = 0;
-	ctxt->last_flash_ticks = ticks;
+	return 0;
 }
 
 
diff --git a/src/modules/voronoi/voronoi.c b/src/modules/voronoi/voronoi.c
index 5b38705..ff5f290 100644
--- a/src/modules/voronoi/voronoi.c
+++ b/src/modules/voronoi/voronoi.c
@@ -357,11 +357,13 @@ static void voronoi_render_fragment(til_module_context_t *context, til_stream_t
 }
 
 
-static void voronoi_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr)
+static int voronoi_finish_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr)
 {
 	voronoi_context_t	*ctxt = (voronoi_context_t *)context;
 
 	ctxt->distances.recalc_needed = 0;
+
+	return 0;
 }
 
 
diff --git a/src/til.c b/src/til.c
index 5a295a5..8fa3b48 100644
--- a/src/til.c
+++ b/src/til.c
@@ -238,6 +238,7 @@ static void module_render_fragment(til_module_context_t *context, til_stream_t *
 
 	module = context->module;
 
+render_again:
 	if (module->prepare_frame) {
 		til_frame_plan_t	frame_plan = {};
 
@@ -269,7 +270,8 @@ static void module_render_fragment(til_module_context_t *context, til_stream_t *
 	}
 
 	if (module->finish_frame) {
-		module->finish_frame(context, stream, ticks, fragment_ptr);
+		if (module->finish_frame(context, stream, ticks, fragment_ptr) > 0)
+			goto render_again;
 		touched++;
 	}
 
diff --git a/src/til.h b/src/til.h
index 0d48239..9fb8b5b 100644
--- a/src/til.h
+++ b/src/til.h
@@ -30,7 +30,7 @@ struct til_module_t {
 	void			(*destroy_context)(til_module_context_t *context);	/* destroy gets stream in context, but the render-related functions should always use the passed-in stream so it can potentially change */
 	void			(*prepare_frame)(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr, til_frame_plan_t *res_frame_plan);
 	void			(*render_fragment)(til_module_context_t *context, til_stream_t *stream, unsigned ticks, unsigned cpu, til_fb_fragment_t **fragment_ptr);
-	void			(*finish_frame)(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr);
+	int			(*finish_frame)(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr);
 	int			(*setup)(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup);
 	char			*name;
 	char			*description;