*: wire up context-specific setup instances

This is a preparatory commit for cleaning up the existing sloppy
global-ish application of settings during the iterative _setup()
call sequences.

Due to how this has evolved from a very rudimentary thing
enjoying many assumptions about there ever only being a single
module instance being configured by the settings, there's a lot
of weirdness and inconsistency surrounding module setup WRT
changes being applied instantaneously to /all/ existing and
future context's renderings of a given module vs. requiring a new
context be created to realize changes.

This commit doesn't actually change any of that, but puts the
plumbing in place for the setup methods to allocate and
initialize a private struct encapsulating the parsed and
validated setup once the settings are complete.  This opaque
setup pointer will then be provided to the associated
create_context() method as the setup pointer.  Then the created
context can configure itself using the provided setup when
non-NULL, or simply use defaults when NULL.

A future commit will update the setup methods to allocate and
populate their respective setup structs, adding the structs as
needed, as well as updating their create_context() methods to
utilize those setups.

One consequence of these changes when fully realized will be that
every setting change will require a new context be created from
the changed settings for the change to be realized.

For settings appropriately manipulated at runtime the concept of
knobs was introduced but never finished.  That will have to be
finished in the future to enable more immediate/interactive
changing of settings-like values appropriate for interactive
manipulation

27 files changed, 62 insertions, 58 deletions

diff --git a/src/drm_fb.c b/src/drm_fb.c
index 02c40bd..67d8e68 100644
--- a/src/drm_fb.c
+++ b/src/drm_fb.c
@@ -283,7 +283,7 @@ static int mode_desc_generator(void *setup_context, const til_setting_desc_t **r
 /* setup is called repeatedly as settings is constructed, until 0 is returned. */
 /* a negative value is returned on error */
 /* positive value indicates another setting is needed, described in next_setting */
-static int drm_fb_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int drm_fb_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	drm_fb_setup_t			context = {};
 	til_setting_desc_generator_t	generators[] = {
diff --git a/src/main.c b/src/main.c
index c19b6b5..15bde39 100644
--- a/src/main.c
+++ b/src/main.c
@@ -51,7 +51,9 @@ static rototiller_t		rototiller;
 
 typedef struct setup_t {
 	til_settings_t	*module;
+	void		*module_setup;
 	til_settings_t	*video;
+	void		*video_setup;
 } setup_t;
 
 /* FIXME: this is unnecessarily copy-pasta, i think modules should just be made
@@ -60,7 +62,7 @@ typedef struct setup_t {
  */
 
 /* select video backend if not yet selected, then setup the selected backend. */
-static int setup_video(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int setup_video(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	til_setting_t	*setting;
 	const char	*video;
@@ -101,14 +103,14 @@ static int setup_video(til_settings_t *settings, til_setting_t **res_setting, co
 	if (!strcmp(video, "drm")) {
 		fb_ops = &drm_fb_ops;
 
-		return drm_fb_ops.setup(settings, res_setting, res_desc);
+		return drm_fb_ops.setup(settings, res_setting, res_desc, res_setup);
 	}
 #endif
 #ifdef HAVE_SDL
 	if (!strcmp(video, "sdl")) {
 		fb_ops = &sdl_fb_ops;
 
-		return sdl_fb_ops.setup(settings, res_setting, res_desc);
+		return sdl_fb_ops.setup(settings, res_setting, res_desc, res_setup);
 	}
 #endif
 
@@ -131,13 +133,13 @@ static int setup_from_args(til_args_t *args, setup_t *res_setup)
 	if (!setup.video)
 		goto _err;
 
-	r = setup_interactively(setup.module, til_module_setup, args->use_defaults);
+	r = setup_interactively(setup.module, til_module_setup, args->use_defaults, &setup.module_setup);
 	if (r < 0)
 		goto _err;
 	if (r)
 		changes = 1;
 
-	r = setup_interactively(setup.video, setup_video, args->use_defaults);
+	r = setup_interactively(setup.video, setup_video, args->use_defaults, &setup.video_setup);
 	if (r < 0)
 		goto _err;
 	if (r)
@@ -274,6 +276,7 @@ int main(int argc, const char *argv[])
 						get_ticks(&rototiller.start_tv,
 							&rototiller.start_tv,
 							rototiller.ticks_offset),
+						setup.module_setup,
 						&rototiller.module_context)) < 0,
 		"unable to create module context: %s", strerror(-r));
 
diff --git a/src/modules/compose/compose.c b/src/modules/compose/compose.c
index b3e2dbc..adf638c 100644
--- a/src/modules/compose/compose.c
+++ b/src/modules/compose/compose.c
@@ -36,10 +36,10 @@ typedef struct compose_context_t {
 	compose_layer_t		layers[];
 } compose_context_t;
 
-static void * compose_create_context(unsigned ticks, unsigned num_cpus);
+static void * compose_create_context(unsigned ticks, unsigned num_cpus, void *setup);
 static void compose_destroy_context(void *context);
 static void compose_prepare_frame(void *context, unsigned ticks, unsigned n_cpus, til_fb_fragment_t *fragment, til_fragmenter_t *res_fragmenter);
-static int compose_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc);
+static int compose_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup);
 
 static char	*compose_default_layers[] = { "drizzle", "stars", "spiro", "plato", NULL };
 static char	**compose_layers;
@@ -55,7 +55,7 @@ til_module_t	compose_module = {
 };
 
 
-static void * compose_create_context(unsigned ticks, unsigned num_cpus)
+static void * compose_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	char			**layers = compose_default_layers;
 	compose_context_t	*ctxt;
@@ -78,7 +78,7 @@ static void * compose_create_context(unsigned ticks, unsigned num_cpus)
 		module = til_lookup_module(layers[i]);
 
 		ctxt->layers[i].module = module;
-		(void) til_module_create_context(module, ticks, &ctxt->layers[i].module_ctxt);
+		(void) til_module_create_context(module, ticks, NULL, &ctxt->layers[i].module_ctxt);
 
 		ctxt->n_layers++;
 	}
@@ -108,7 +108,7 @@ static void compose_prepare_frame(void *context, unsigned ticks, unsigned n_cpus
 }
 
 
-static int compose_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int compose_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*layers;
 	int		r;
diff --git a/src/modules/drizzle/drizzle.c b/src/modules/drizzle/drizzle.c
index 294d671..0a53492 100644
--- a/src/modules/drizzle/drizzle.c
+++ b/src/modules/drizzle/drizzle.c
@@ -64,7 +64,7 @@ static inline uint32_t color_to_uint32(v3f_t color) {
 }
 
 
-static void * drizzle_create_context(unsigned ticks, unsigned num_cpus)
+static void * drizzle_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	drizzle_context_t	*ctxt;
 
@@ -153,7 +153,7 @@ static void drizzle_render_fragment(void *context, unsigned ticks, unsigned cpu,
 }
 
 
-static int drizzle_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int drizzle_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*viscosity;
 	const char	*values[] = {
diff --git a/src/modules/flui2d/flui2d.c b/src/modules/flui2d/flui2d.c
index 7a30c7e..cf6024b 100644
--- a/src/modules/flui2d/flui2d.c
+++ b/src/modules/flui2d/flui2d.c
@@ -185,7 +185,7 @@ typedef struct flui2d_context_t {
 } flui2d_context_t;
 
 
-static void * flui2d_create_context(unsigned ticks, unsigned num_cpus)
+static void * flui2d_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	flui2d_context_t	*ctxt;
 
@@ -283,7 +283,7 @@ static void flui2d_render_fragment(void *context, unsigned ticks, unsigned cpu,
 
 
 /* Settings hooks for configurable variables */
-static int flui2d_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int flui2d_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*viscosity;
 	const char	*diffusion;
diff --git a/src/modules/julia/julia.c b/src/modules/julia/julia.c
index f00c44c..dfe6726 100644
--- a/src/modules/julia/julia.c
+++ b/src/modules/julia/julia.c
@@ -66,7 +66,7 @@ static uint32_t	colors[] = {
 		};
 
 
-static void * julia_create_context(unsigned ticks, unsigned num_cpus)
+static void * julia_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	return calloc(1, sizeof(julia_context_t));
 }
diff --git a/src/modules/meta2d/meta2d.c b/src/modules/meta2d/meta2d.c
index c1b2a8a..ddf20f1 100644
--- a/src/modules/meta2d/meta2d.c
+++ b/src/modules/meta2d/meta2d.c
@@ -66,7 +66,7 @@ static inline uint32_t color_to_uint32(v3f_t color) {
 }
 
 
-static void * meta2d_create_context(unsigned ticks, unsigned num_cpus)
+static void * meta2d_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	meta2d_context_t	*ctxt;
 
diff --git a/src/modules/montage/montage.c b/src/modules/montage/montage.c
index 5782782..5a9b688 100644
--- a/src/modules/montage/montage.c
+++ b/src/modules/montage/montage.c
@@ -16,7 +16,7 @@ typedef struct montage_context_t {
 } montage_context_t;
 
 static void setup_next_module(montage_context_t *ctxt);
-static void * montage_create_context(unsigned ticks, unsigned num_cpus);
+static void * montage_create_context(unsigned ticks, unsigned num_cpus, void *setup);
 static void montage_destroy_context(void *context);
 static void montage_prepare_frame(void *context, unsigned ticks, unsigned n_cpus, til_fb_fragment_t *fragment, til_fragmenter_t *res_fragmenter);
 static void montage_render_fragment(void *context, unsigned ticks, unsigned cpu, til_fb_fragment_t *fragment);
@@ -32,7 +32,7 @@ til_module_t	montage_module = {
 };
 
 
-static void * montage_create_context(unsigned ticks, unsigned num_cpus)
+static void * montage_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	const til_module_t	**modules, *rtv_module, *compose_module;
 	size_t			n_modules;
@@ -90,7 +90,7 @@ static void * montage_create_context(unsigned ticks, unsigned num_cpus)
 		const til_module_t	*module = ctxt->modules[i];
 
 		if (module->create_context)	/* FIXME errors */
-			ctxt->contexts[i] = module->create_context(ticks, 1);
+			ctxt->contexts[i] = module->create_context(ticks, 1, NULL);
 	}
 
 	return ctxt;
diff --git a/src/modules/pixbounce/pixbounce.c b/src/modules/pixbounce/pixbounce.c
index 3efa797..d016ff7 100644
--- a/src/modules/pixbounce/pixbounce.c
+++ b/src/modules/pixbounce/pixbounce.c
@@ -109,7 +109,7 @@ static int pick_pix(int num_pics, int last_pic)
 	return pix_num;
 }
 
-static void * pixbounce_create_context(unsigned ticks, unsigned num_cpus)
+static void * pixbounce_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	pixbounce_context_t *ctxt;
 
diff --git a/src/modules/plasma/plasma.c b/src/modules/plasma/plasma.c
index 7598fe3..c6380ef 100644
--- a/src/modules/plasma/plasma.c
+++ b/src/modules/plasma/plasma.c
@@ -52,7 +52,7 @@ static void init_plasma(int32_t *costab, int32_t *sintab)
 }
 
 
-static void * plasma_create_context(unsigned ticks, unsigned num_cpus)
+static void * plasma_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	static int	initialized;
 
diff --git a/src/modules/plato/plato.c b/src/modules/plato/plato.c
index 05d80cb..c8aba18 100644
--- a/src/modules/plato/plato.c
+++ b/src/modules/plato/plato.c
@@ -609,7 +609,7 @@ static void draw_polyhedron(const polyhedron_t *polyhedron, m4f_t *transform, ti
 }
 
 
-static void * plato_create_context(unsigned ticks, unsigned num_cpus)
+static void * plato_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	plato_context_t	*ctxt;
 
diff --git a/src/modules/ray/ray.c b/src/modules/ray/ray.c
index 06b0180..79e14ce 100644
--- a/src/modules/ray/ray.c
+++ b/src/modules/ray/ray.c
@@ -130,7 +130,7 @@ typedef struct ray_context_t {
 } ray_context_t;
 
 
-static void * ray_create_context(unsigned ticks, unsigned num_cpus)
+static void * ray_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	return calloc(1, sizeof(ray_context_t));
 }
diff --git a/src/modules/roto/roto.c b/src/modules/roto/roto.c
index 7aff770..ac66987 100644
--- a/src/modules/roto/roto.c
+++ b/src/modules/roto/roto.c
@@ -32,7 +32,7 @@ static int32_t	costab[FIXED_TRIG_LUT_SIZE], sintab[FIXED_TRIG_LUT_SIZE];
 static uint8_t	texture[256][256];
 static color_t	palette[2];
 
-static void * roto_create_context(unsigned ticks, unsigned num_cpus)
+static void * roto_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	return calloc(1, sizeof(roto_context_t));
 }
diff --git a/src/modules/rtv/rtv.c b/src/modules/rtv/rtv.c
index 1804613..b49ac37 100644
--- a/src/modules/rtv/rtv.c
+++ b/src/modules/rtv/rtv.c
@@ -24,6 +24,7 @@
 typedef struct rtv_channel_t {
 	const til_module_t	*module;
 	void			*module_ctxt;
+	void			*module_setup;
 	time_t			last_on_time, cumulative_time;
 	char			*settings;
 	txt_t			*caption;
@@ -44,11 +45,11 @@ typedef struct rtv_context_t {
 } rtv_context_t;
 
 static void setup_next_channel(rtv_context_t *ctxt, unsigned ticks);
-static void * rtv_create_context(unsigned ticks, unsigned num_cpus);
+static void * rtv_create_context(unsigned ticks, unsigned num_cpus, void *setup);
 static void rtv_destroy_context(void *context);
 static void rtv_prepare_frame(void *context, unsigned ticks, unsigned n_cpus, til_fb_fragment_t *fragment, til_fragmenter_t *res_fragmenter);
 static void rtv_finish_frame(void *context, unsigned ticks, til_fb_fragment_t *fragment);
-static int rtv_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc);
+static int rtv_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup);
 
 static unsigned rtv_duration = RTV_DURATION_SECS;
 static unsigned rtv_context_duration = RTV_CONTEXT_DURATION_SECS;
@@ -92,7 +93,7 @@ static void randomize_channels(rtv_context_t *ctxt)
 }
 
 
-static char * randomize_module_setup(const til_module_t *module)
+static char * randomize_module_setup(const til_module_t *module, void **res_setup)
 {
 	til_settings_t			*settings;
 	til_setting_t			*setting;
@@ -106,7 +107,7 @@ static char * randomize_module_setup(const til_module_t *module)
 	if (!settings)
 		return NULL;
 
-	while (module->setup(settings, &setting, &desc) > 0) {
+	while (module->setup(settings, &setting, &desc, res_setup) > 0) {
 		if (desc->random) {
 			char	*value;
 
@@ -181,7 +182,7 @@ static void setup_next_channel(rtv_context_t *ctxt, unsigned ticks)
 			char	*settings;
 			txt_t	*caption;
 
-			settings = randomize_module_setup(ctxt->channel->module);
+			settings = randomize_module_setup(ctxt->channel->module, &ctxt->channel->module_setup);
 			caption = txt_newf("Title: %s%s%s\nDescription: %s%s%s",
 						 ctxt->channel->module->name,
 						 ctxt->channel->module->author ? "\nAuthor: " : "",
@@ -199,7 +200,7 @@ static void setup_next_channel(rtv_context_t *ctxt, unsigned ticks)
 	}
 
 	if (!ctxt->channel->module_ctxt)
-		(void) til_module_create_context(ctxt->channel->module, ticks, &ctxt->channel->module_ctxt);
+		(void) til_module_create_context(ctxt->channel->module, ticks, ctxt->channel->module_setup, &ctxt->channel->module_ctxt);
 
 	ctxt->channel->last_on_time = now;
 }
@@ -223,7 +224,7 @@ static int rtv_should_skip_module(const rtv_context_t *ctxt, const til_module_t
 }
 
 
-static void * rtv_create_context(unsigned ticks, unsigned num_cpus)
+static void * rtv_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	rtv_context_t		*ctxt;
 	const til_module_t	**modules;
@@ -241,7 +242,7 @@ static void * rtv_create_context(unsigned ticks, unsigned num_cpus)
 	ctxt->snow_channel.module = &none_module;
 	if (rtv_snow_module) {
 		ctxt->snow_channel.module = til_lookup_module(rtv_snow_module);
-		(void) til_module_create_context(ctxt->snow_channel.module, ticks, &ctxt->snow_channel.module_ctxt);
+		(void) til_module_create_context(ctxt->snow_channel.module, ticks, NULL, &ctxt->snow_channel.module_ctxt);
 	}
 
 	for (size_t i = 0; i < n_modules; i++) {
@@ -307,7 +308,7 @@ static void rtv_finish_frame(void *context, unsigned ticks, til_fb_fragment_t *f
 }
 
 
-static int rtv_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int rtv_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*channels;
 	const char	*duration;
diff --git a/src/modules/snow/snow.c b/src/modules/snow/snow.c
index cffc10c..f61f2e9 100644
--- a/src/modules/snow/snow.c
+++ b/src/modules/snow/snow.c
@@ -20,7 +20,7 @@ typedef struct snow_context_t {
 } snow_context_t;
 
 
-static void * snow_create_context(unsigned ticks, unsigned n_cpus)
+static void * snow_create_context(unsigned ticks, unsigned n_cpus, void *setup)
 {
 	snow_context_t	*ctxt;
 
diff --git a/src/modules/sparkler/sparkler.c b/src/modules/sparkler/sparkler.c
index 7cebfcd..51184b1 100644
--- a/src/modules/sparkler/sparkler.c
+++ b/src/modules/sparkler/sparkler.c
@@ -25,7 +25,7 @@ extern particle_ops_t	simple_ops;
 
 static particles_conf_t	sparkler_conf;
 
-static void * sparkler_create_context(unsigned ticks, unsigned num_cpus)
+static void * sparkler_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	static int		initialized;
 	sparkler_context_t	*ctxt;
@@ -96,7 +96,7 @@ static void sparkler_render_fragment(void *context, unsigned ticks, unsigned cpu
 
 
 /* Settings hooks for configurable variables */
-static int sparkler_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int sparkler_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*show_bsp_leafs;
 	const char	*show_bsp_matches;
diff --git a/src/modules/spiro/spiro.c b/src/modules/spiro/spiro.c
index 7f31ddb..20fd7f0 100644
--- a/src/modules/spiro/spiro.c
+++ b/src/modules/spiro/spiro.c
@@ -29,7 +29,7 @@ typedef struct spiro_context_t {
 } spiro_context_t;
 
 
-static void * spiro_create_context(unsigned ticks, unsigned num_cpus)
+static void * spiro_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	spiro_context_t *ctxt;
 	float		z;
diff --git a/src/modules/stars/stars.c b/src/modules/stars/stars.c
index 859fb1f..055a495 100644
--- a/src/modules/stars/stars.c
+++ b/src/modules/stars/stars.c
@@ -41,7 +41,7 @@ float get_random_unit_coord() {
 }
 
 
-static void * stars_create_context(unsigned ticks, unsigned num_cpus)
+static void * stars_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	stars_context_t *ctxt;
 	float		z;
@@ -201,7 +201,7 @@ static void stars_render_fragment(void *context, unsigned ticks, unsigned cpu, t
 	ctxt->offset_y = tmp_y;
 }
 
-int stars_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+int stars_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*rot_adj;
 	const char	*rot_adj_values[] = {
diff --git a/src/modules/submit/submit.c b/src/modules/submit/submit.c
index db5cf29..a2dea77 100644
--- a/src/modules/submit/submit.c
+++ b/src/modules/submit/submit.c
@@ -261,7 +261,7 @@ static void setup_grid(submit_context_t *ctxt)
 }
 
 
-static void * submit_create_context(unsigned ticks, unsigned num_cpus)
+static void * submit_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	submit_context_t	*ctxt;
 
@@ -322,7 +322,7 @@ static void submit_render_fragment(void *context, unsigned ticks, unsigned cpu,
 }
 
 
-static int submit_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int submit_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*values[] = {
 				"off",
diff --git a/src/modules/swab/swab.c b/src/modules/swab/swab.c
index fee20cf..b64ca2b 100644
--- a/src/modules/swab/swab.c
+++ b/src/modules/swab/swab.c
@@ -65,7 +65,7 @@ static inline uint32_t color_to_uint32(color_t color) {
 }
 
 
-static void * swab_create_context(unsigned ticks, unsigned num_cpus)
+static void * swab_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	swab_context_t	*ctxt;
 
diff --git a/src/modules/swarm/swarm.c b/src/modules/swarm/swarm.c
index 8ff4812..ffaaa1d 100644
--- a/src/modules/swarm/swarm.c
+++ b/src/modules/swarm/swarm.c
@@ -170,7 +170,7 @@ static inline uint32_t color_to_uint32(v3f_t color) {
 }
 
 
-static void * swarm_create_context(unsigned ticks, unsigned num_cpus)
+static void * swarm_create_context(unsigned ticks, unsigned num_cpus, void *setup)
 {
 	swarm_context_t	*ctxt;
 
@@ -408,7 +408,7 @@ static void swarm_render_fragment(void *context, unsigned ticks, unsigned cpu, t
 }
 
 
-static int swarm_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int swarm_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*styles[] = {
 				"points",
diff --git a/src/sdl_fb.c b/src/sdl_fb.c
index 6aa535b..72bc7b6 100644
--- a/src/sdl_fb.c
+++ b/src/sdl_fb.c
@@ -26,7 +26,7 @@ struct sdl_fb_page_t {
 };
 
 
-static int sdl_fb_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+static int sdl_fb_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	const char	*fullscreen_values[] = {
 				"off",
diff --git a/src/setup.c b/src/setup.c
index c811887..8f2708d 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -21,7 +21,7 @@ static int add_value(til_settings_t *settings, const char *key, const char *valu
 
 
 /* returns negative on error, otherwise number of additions made to settings */
-int setup_interactively(til_settings_t *settings, int (*setup_func)(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc), int defaults)
+int setup_interactively(til_settings_t *settings, int (*setup_func)(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup), int defaults, void **res_setup)
 {
 	unsigned			additions = 0;
 	char				buf[256] = "\n";
@@ -34,7 +34,7 @@ int setup_interactively(til_settings_t *settings, int (*setup_func)(til_settings
 
 	/* TODO: regex and error handling */
 
-	while ((r = setup_func(settings, &setting, &desc)) > 0) {
+	while ((r = setup_func(settings, &setting, &desc, res_setup)) > 0) {
 		additions++;
 
 		/* if setup_func() has returned a description for an undescribed preexisting setting,
diff --git a/src/setup.h b/src/setup.h
index 2c79fed..a32f57c 100644
--- a/src/setup.h
+++ b/src/setup.h
@@ -3,6 +3,6 @@
 
 #include "til_settings.h"
 
-int setup_interactively(til_settings_t *settings, int (*setup_func)(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc), int defaults);
+int setup_interactively(til_settings_t *settings, int (*setup_func)(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup), int defaults, void **res_setup);
 
 #endif
diff --git a/src/til.c b/src/til.c
index 4d7ef63..3cbd294 100644
--- a/src/til.c
+++ b/src/til.c
@@ -144,7 +144,7 @@ void til_module_render(const til_module_t *module, void *context, unsigned ticks
 }
 
 
-int til_module_create_context(const til_module_t *module, unsigned ticks, void **res_context)
+int til_module_create_context(const til_module_t *module, unsigned ticks, void *setup, void **res_context)
 {
 	void	*context;
 
@@ -154,7 +154,7 @@ int til_module_create_context(const til_module_t *module, unsigned ticks, void *
 	if (!module->create_context)
 		return 0;
 
-	context = module->create_context(ticks, til_threads_num_threads(til_threads));
+	context = module->create_context(ticks, til_threads_num_threads(til_threads), setup);
 	if (!context)
 		return -ENOMEM;
 
@@ -178,7 +178,7 @@ void * til_module_destroy_context(const til_module_t *module, void *context)
 
 
 /* select module if not yet selected, then setup the module. */
-int til_module_setup(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
+int til_module_setup(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup)
 {
 	til_setting_t		*setting;
 	const til_module_t	*module;
@@ -217,7 +217,7 @@ int til_module_setup(til_settings_t *settings, til_setting_t **res_setting, cons
 		return -EINVAL;
 
 	if (module->setup)
-		return module->setup(settings, res_setting, res_desc);
+		return module->setup(settings, res_setting, res_desc, res_setup);
 
 	return 0;
 }
diff --git a/src/til.h b/src/til.h
index 6c6c745..29bbb2c 100644
--- a/src/til.h
+++ b/src/til.h
@@ -12,12 +12,12 @@ typedef struct til_setting_desc_t til_setting_desc_t;
 typedef struct til_knob_t til_knob_t;
 
 typedef struct til_module_t {
-	void *	(*create_context)(unsigned ticks, unsigned n_cpus);
+	void *	(*create_context)(unsigned ticks, unsigned n_cpus, void *setup);
 	void	(*destroy_context)(void *context);
 	void	(*prepare_frame)(void *context, unsigned ticks, unsigned n_cpus, til_fb_fragment_t *fragment, til_fragmenter_t *res_fragmenter);
 	void	(*render_fragment)(void *context, unsigned ticks, unsigned cpu, til_fb_fragment_t *fragment);
 	void	(*finish_frame)(void *context, unsigned ticks, til_fb_fragment_t *fragment);
-	int	(*setup)(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc);
+	int	(*setup)(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup);
 	size_t	(*knobs)(void *context, til_knob_t **res_knobs);
 	char	*name;
 	char	*description;
@@ -30,8 +30,8 @@ void til_shutdown(void);
 const til_module_t * til_lookup_module(const char *name);
 void til_get_modules(const til_module_t ***res_modules, size_t *res_n_modules);
 void til_module_render(const til_module_t *module, void *context, unsigned ticks, til_fb_fragment_t *fragment);
-int til_module_create_context(const til_module_t *module, unsigned ticks, void **res_context);
+int til_module_create_context(const til_module_t *module, unsigned ticks, void *setup, void **res_context);
 void * til_module_destroy_context(const til_module_t *module, void *context);
-int til_module_setup(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc);
+int til_module_setup(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup);
 
 #endif
diff --git a/src/til_fb.h b/src/til_fb.h
index f6a2972..bc553c6 100644
--- a/src/til_fb.h
+++ b/src/til_fb.h
@@ -35,7 +35,7 @@ typedef struct til_fb_t til_fb_t;
 
 /* Supply this struct to fb_new() with the appropriate context */
 typedef struct til_fb_ops_t {
-	int	(*setup)(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc);
+	int	(*setup)(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, void **res_setup);
 	int	(*init)(const til_settings_t *settings, void **res_context);
 	void	(*shutdown)(til_fb_t *fb, void *context);
 	int	(*acquire)(til_fb_t *fb, void *context, void *page);