path: root/src/modules/checkers/checkers.c

/*
 *  Copyright (C) 2022 - Vito Caputo - <vcaputo@pengaru.com>
 *
 *  This program is free software: you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License version 2 as published
 *  by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <errno.h>
#include <stdlib.h>
#include <unistd.h>

#include "til.h"
#include "til_fb.h"
#include "til_module_context.h"


#define CHECKERS_DEFAULT_SIZE		32
#define CHECKERS_DEFAULT_PATTERN	CHECKERS_PATTERN_CHECKERED
#define CHECKERS_DEFAULT_DYNAMICS	CHECKERS_DYNAMICS_ODD
#define CHECKERS_DEFAULT_DYNAMICS_RATE	1.0
#define CHECKERS_DEFAULT_FILL		CHECKERS_FILL_COLOR
#define CHECKERS_DEFAULT_COLOR		0xffffff
#define CHECKERS_DEFAULT_FILL_MODULE	"none"


typedef enum checkers_pattern_t {
	CHECKERS_PATTERN_CHECKERED,
	CHECKERS_PATTERN_RANDOM,
} checkers_pattern_t;

typedef enum checkers_dynamics_t {
	CHECKERS_DYNAMICS_ODD,
	CHECKERS_DYNAMICS_EVEN,
	CHECKERS_DYNAMICS_ALTERNATING,
	CHECKERS_DYNAMICS_RANDOM,
} checkers_dynamics_t;

typedef enum checkers_fill_t {
	CHECKERS_FILL_COLOR,
	CHECKERS_FILL_SAMPLED,
	CHECKERS_FILL_TEXTURED,
	CHECKERS_FILL_RANDOM,
	CHECKERS_FILL_MIXED,
} checkers_fill_t;

typedef struct checkers_setup_t {
	til_setup_t		til_setup;
	unsigned		size;
	checkers_pattern_t	pattern;
	checkers_dynamics_t	dynamics;
	float			rate;
	checkers_fill_t		fill;
	uint32_t		color;
	const til_module_t	*fill_module;
	til_setup_t		*fill_module_setup;
} checkers_setup_t;

typedef struct checkers_context_t {
	til_module_context_t	til_module_context;
	checkers_setup_t	*setup;
	til_module_context_t	*fill_module_contexts[];
} checkers_context_t;


static til_module_context_t * checkers_create_context(const til_module_t *module, til_stream_t *stream, unsigned seed, unsigned ticks, unsigned n_cpus, char *path, til_setup_t *setup)
{
	size_t			size = sizeof(checkers_context_t);
	checkers_context_t	*ctxt;

	if (((checkers_setup_t *)setup)->fill_module)
		size += sizeof(til_module_context_t *) * n_cpus;

	ctxt = til_module_context_new(module, size, stream, ticks, seed, n_cpus, path, setup);
	if (!ctxt)
		return NULL;

	ctxt->setup = (checkers_setup_t *)setup;

	if (ctxt->setup->fill_module) {
		const til_module_t	*module = ctxt->setup->fill_module;
		size_t			fill_module_path_len = snprintf(NULL, 0, "%s/fill_module", path) + 1; /* FIXME TODO: revisit path construction, see big comment in modules/compose FIXME TODO */
		char			*fill_module_path = calloc(1, fill_module_path_len);

		if (!fill_module_path)
			return til_module_context_free(&ctxt->til_module_context);

		snprintf(fill_module_path, fill_module_path_len, "%s/fill_module", path);

		/* since checkers is already threaded, create an n_cpus=1 context per-cpu */
		for (unsigned i = 0; i < n_cpus; i++) /* TODO: errors */
			(void) til_module_create_context(module, stream, seed, ticks, 1, fill_module_path, ctxt->setup->fill_module_setup, &ctxt->fill_module_contexts[i]);
			 /* FIXME TODO ^^^ sharing the fill_module_path across the per-cpu contexts aliases them _across_threads_ no less, this needs attention/thought FIXME TODO */
			 /* but the problem with just doing something like suffixing the cpu # to give each context a unique path per-cpu is then the taps/pipes would all be
			  * unique on a per-cpu basis.  That's _very_ undesirable in terms of sequencing the pipes by name, we don't want sequencing tracks per-cpu and that's
			  * a non-deterministic quantity depending on the host anyways.  So the path can't encode a cpu number, that's just a hard NOPE.  What may need to be
			  * done here is to stop creating the context per-cpu in checkers and instead be able to simply do a single n_cpus create context at the single path,
			  * then be able to perform a forced cpu-specific render on a given context.  Then whatever the context-specific module does with threaded rendering
			  * on a shared context is its problem, and we already told it the n_cpus value so it could do whatever it needed to.  The problem with this as-is is
			  * that some modules just don't implement threaded rendering at all and can't share their context across threads as a result, so checkers can't make
			  * that assumption.  This hack here of creating a context per-cpu works around that problem entirely, so even simple modules magically become threaded.
			  * Maybe what needs to happen is everything path-bound needs to just have some magic surrounding cpu-local state.  As in, the tap/tap-driving stuff could
			  * just roll with the punches and share the first instance of tap variables then all the others just get left alone. FIXME TODO FIXME TODO
			  */

		free(fill_module_path);
		/* XXX: it would be interesting to support various patterns/layouts by varying the seed, but this will require
		 * more complex context allocation strategies while also maintaining the per-cpu allocation.
		 */
	}

	return &ctxt->til_module_context;
}


static void checkers_destroy_context(til_module_context_t *context)
{
	checkers_context_t	*ctxt = (checkers_context_t *)context;

	if (ctxt->setup->fill_module) {
		for (unsigned i = 0; i < context->n_cpus; i++)
			til_module_context_free(ctxt->fill_module_contexts[i]);
	}

	free(ctxt);
}


/* This is derived from til_fb_fragment_tile_single() with two variations:
 * 1. when the size doesn't align with frame size, the start tiles are offset
 *    to center the checkers letting the edge checkers all clip as needed
 * 2. the incoming frame width isn't propagated down to the tiled fragments,
 *    though for the potentially clipped boundary tiles the frame_{width,height}
 *    won't match the incoming width,height.
 *
 * XXX note this fragmenter in particular really exercises fill_modules' correct handling
 *     of frame vs. fragment dimensions and clipping semantics
 */
int checkers_fragment_tile_single(const til_fb_fragment_t *fragment, unsigned tile_size, unsigned number, til_fb_fragment_t *res_fragment)
{
	unsigned	w = fragment->width / tile_size, h = fragment->height / tile_size;
	unsigned	tiled_w = w * tile_size, tiled_h = h * tile_size;
	unsigned	x, y, xoff, yoff, xshift = 0, yshift = 0;

	assert(fragment);
	assert(res_fragment);

	/* Detect the need for fractional tiles on both axis and shift the fragments
	 * to keep the overall checkered output centered.  This complicates res_fragment.{x,y,width,height}
	 * calculations for the peripheral checker tiles as those must clip when shifted.
	 */
	if (tiled_w < fragment->width) {
		tiled_w += tile_size;
		xshift = (tiled_w - fragment->width) >> 1;
		w++;
	}

	if (tiled_h < fragment->height) {
		tiled_h += tile_size;
		yshift = (tiled_h - fragment->height) >> 1;
		h++;
	}

	y = number / w;
	if (y >= h)
		return 0;

	x = number - (y * w);

	xoff = x * tile_size;
	yoff = y * tile_size;

	if (fragment->texture) {
		assert(res_fragment->texture);
		assert(fragment->frame_width == fragment->texture->frame_width);
		assert(fragment->frame_height == fragment->texture->frame_height);
		assert(fragment->width == fragment->texture->width);
		assert(fragment->height == fragment->texture->height);
		assert(fragment->x == fragment->texture->x);
		assert(fragment->y == fragment->texture->y);

		*(res_fragment->texture) = (til_fb_fragment_t){
					.buf = fragment->texture->buf + (yoff * fragment->texture->pitch) - (y ? (yshift * fragment->texture->pitch) : 0) + (xoff - (x ? xshift : 0)),
					.width = MIN(fragment->width - (xoff - xshift), x ? tile_size : (tile_size - xshift)),
					.height = MIN(fragment->height - (yoff - yshift), y ? tile_size : (tile_size - yshift)),
					.x = x ? 0 : xshift,
					.y = y ? 0 : yshift,
					.frame_width = tile_size,
					.frame_height = tile_size,
					.stride = fragment->texture->stride + (fragment->width - MIN(fragment->width - (xoff - xshift), x ? tile_size : (tile_size - xshift))),
					.pitch = fragment->texture->pitch,
					.cleared = fragment->texture->cleared,
				};
	}

	*res_fragment = (til_fb_fragment_t){
				.texture = fragment->texture ? res_fragment->texture : NULL,
				/* TODO: copy pasta! */
				.buf = fragment->buf + (yoff * fragment->pitch) - (y ? (yshift * fragment->pitch) : 0) + (xoff - (x ? xshift : 0)),
				.width = MIN(fragment->width - (xoff - xshift), x ? tile_size : (tile_size - xshift)),
				.height = MIN(fragment->height - (yoff - yshift), y ? tile_size : (tile_size - yshift)),
				.x = x ? 0 : xshift,
				.y = y ? 0 : yshift,
				// this is a little janky but leave frame_width to be set by render_fragment
				// so it can use the old frame_width for determining checkered state
				.frame_width = fragment->width, // becomes tile_size
				.frame_height = fragment->height, // becomes tile_size
				.stride = fragment->stride + (fragment->width - MIN(fragment->width - (xoff - xshift), x ? tile_size : (tile_size - xshift))),
				.pitch = fragment->pitch,
				.number = number,
				.cleared = fragment->cleared,
			};

	return 1;
}


static int checkers_fragmenter(til_module_context_t *context, const til_fb_fragment_t *fragment, unsigned number, til_fb_fragment_t *res_fragment)
{
	checkers_context_t	*ctxt = (checkers_context_t *)context;

	return checkers_fragment_tile_single(fragment, ctxt->setup->size, number, res_fragment);
}


static void checkers_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)
{
	checkers_context_t	*ctxt = (checkers_context_t *)context;
	til_fb_fragment_t	*fragment = *fragment_ptr;

	/* XXX: note cpu_affinity is required when fill_module is used, to ensure module_contexts
	 * have a stable relationship to fragnum.  Otherwise the output would be unstable because the
	 * module contexts would be randomly distributed across the filled checkers frame-to-frame.
	 * This is unfortunate since cpu_affinity is likely to be slower than just letting the render
	 * threads render fragments in whatever order (the preferred default).  fill_module here
	 * is actually *the* reason til_frame_plan_t.cpu_affinity got implemented, before this there
	 * wasn't even a til_frame_plan_t container; a bare til_fragmenter_t was returned.
	 */
	*res_frame_plan = (til_frame_plan_t){ .fragmenter = checkers_fragmenter, .cpu_affinity = !!ctxt->setup->fill_module };
}


static inline unsigned hash(unsigned x)
{
	x = ((x >> 16) ^ x) * 0x61C88647;
	x = ((x >> 16) ^ x) * 0x61C88647;
	x = ((x >> 16) ^ x) * 0x61C88647;
	x = (x >> 16) ^ x;

	return x;
}


static void checkers_render_fragment(til_module_context_t *context, til_stream_t *stream, unsigned ticks, unsigned cpu, til_fb_fragment_t **fragment_ptr)
{
	checkers_context_t	*ctxt = (checkers_context_t *)context;
	til_fb_fragment_t	*fragment = *fragment_ptr;

	uint32_t		color = ctxt->setup->color, flags = 0;
	checkers_fill_t		fill = ctxt->setup->fill;
	int			state;

	switch (ctxt->setup->pattern) {
	case CHECKERS_PATTERN_CHECKERED: {
		unsigned	tiles_per_row, row, col;

		tiles_per_row = fragment->frame_width / ctxt->setup->size;
		if (tiles_per_row * ctxt->setup->size < fragment->frame_width)
			tiles_per_row++;

		row = fragment->number / tiles_per_row;
		col = fragment->number % tiles_per_row;
		state = (row ^ col) & 0x1;
		break;
	}
	case CHECKERS_PATTERN_RANDOM:
		state = hash(fragment->number * 0x61C88647) & 0x1;
		break;
	}

	/* now that state has been determined, set the frame size */
	fragment->frame_width = ctxt->setup->size;
	fragment->frame_height = ctxt->setup->size;

	switch (ctxt->setup->dynamics) {
	case CHECKERS_DYNAMICS_ODD:
		break;
	case CHECKERS_DYNAMICS_EVEN:
		state = ~state & 0x1;
		break;
	case CHECKERS_DYNAMICS_ALTERNATING:
		state ^= ((unsigned)((float)ticks * ctxt->setup->rate) & 0x1);
		break;
	case CHECKERS_DYNAMICS_RANDOM: /* note: the big multiply here is just to get up out of the low bits */
		state &= hash(fragment->number * 0x61C88647 + (unsigned)((float)ticks * ctxt->setup->rate)) & 0x1;
		break;
	}

	if (fill == CHECKERS_FILL_RANDOM || fill == CHECKERS_FILL_MIXED)
		fill = rand_r(&ctxt->til_module_context.seed) % CHECKERS_FILL_RANDOM; /* TODO: mixed should have a setting for controlling the ratios */

	switch (ctxt->setup->fill) {
	case CHECKERS_FILL_SAMPLED:
		if (fragment->cleared)
			color = til_fb_fragment_get_pixel_unchecked(fragment, fragment->x + (fragment->width >> 1), fragment->y + (fragment->height >> 1));
		break;
	case CHECKERS_FILL_TEXTURED:
		flags = TIL_FB_DRAW_FLAG_TEXTURABLE;
		break;
	case CHECKERS_FILL_COLOR:
	default:
		break;
	}

	if (!state)
		til_fb_fragment_clear(fragment);
	else {
		if (!ctxt->setup->fill_module)
			til_fb_fragment_fill(fragment, flags, color);
		else {
			/* TODO: we need a way to send down color and flags, and use the module render as a brush of sorts */
			til_module_render(ctxt->fill_module_contexts[cpu], stream, ticks, fragment_ptr);
		}
	}
}


/* TODO: migrate to libtil */
static char * checkers_random_color(unsigned seed)
{
	/* til should probably have a common randomize color helper for this with a large collection of
	 * reasonable colors, and maybe even have themed palettes one can choose from... */
	static const char *	colors[] = {
					"#ffffff",
					"#ff0000",
					"#00ff00",
					"#0000ff",
					"#ffff00",
					"#00ffff",
					"#ff00ff",
				};

	return strdup(colors[seed % nelems(colors)]);
}


/* TODO: migrate to libtil */
static int checkers_rgb_to_uint32(const char *in, uint32_t *out)
{
	uint32_t	color = 0;

	/* this isn't html, but accept #rrggbb syntax */
	if (*in == '#')
		in++;
	else if (in[0] == '0' && in[1] == 'x') /* and 0xrrggbb */
		in += 2;

	if (strlen(in) != 6)
		return -EINVAL;

	for (int i = 0; i < 6;) {
		uint8_t	c = 0;

		color <<= 8;

		for (int j = 0; j < 2; in++, j++, i++) {
			c <<= 4;

			switch (*in) {
			case '0'...'9':
				c |= (*in) - '0';
				break;

			case 'a'...'f':
				c |= (*in) - 'a' + 10;
				break;

			case 'A'...'F':
				c |= (*in) - 'A' + 10;
				break;

			default:
				return -EINVAL;
			}
		}

		color |= c;
	}

	*out = color;

	return 0;
}


static void checkers_setup_free(til_setup_t *setup)
{
	checkers_setup_t	*s = (checkers_setup_t *)setup;

	if (s) {
		til_setup_free(s->fill_module_setup);
		free(setup);
	}
}


static int checkers_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup)
{
	const char		*size;
	const char		*pattern;
	const char		*fill_module;
	const til_settings_t	*fill_module_settings;
	const char		*dynamics;
	const char		*dynamics_rate;
	const char		*fill;
	const char		*color;
	const char		*size_values[] = {
					"4",
					"8",
					"16",
					"32",
					"64",
					"128",
					NULL
				};
	const char		*pattern_values[] = {
					"checkered",
					"random",
					NULL
				};
	const char		*fill_module_values[] = {
					"none",
					"blinds",
					"moire",
					"pixbounce",
					"plato",
					"roto",
					"shapes",
					"snow",
					"spiro",
					"stars",
					NULL
				};
	const char		*dynamics_values[] = {
					"odd",
					"even",
					"alternating",
					"random",
					NULL
				};
	const char		*dynamics_rate_values[] = {
					"1.0",
					".75",
					".5",
					".25",
					".1",
					".01",
					".001",
					".0001",
					NULL
				};
	const char		*fill_values[] = {
					"color",
					"sampled",
					"textured",
					"random",
					"mixed",
					NULL
				};
	int			r;

	r = til_settings_get_and_describe_value(settings,
						&(til_setting_spec_t){
							.name = "Checker size",
							.key = "size",
							.regex = "\\.[0-9]+",
							.preferred = TIL_SETTINGS_STR(CHECKERS_DEFAULT_SIZE),
							.values = size_values,
							.annotations = NULL
						},
						&size,
						res_setting,
						res_desc);
	if (r)
		return r;

	r = til_settings_get_and_describe_value(settings,
						&(til_setting_spec_t){
							.name = "Checkers pattern",
							.key = "pattern",
							.preferred = pattern_values[0],
							.values = pattern_values,
							.annotations = NULL
						},
						&pattern,
						res_setting,
						res_desc);
	if (r)
		return r;

	r = til_settings_get_and_describe_value(settings,
						&(til_setting_spec_t){
							.name = "Filled cell module (\"none\" for plain checkers)",
							.key = "fill_module",
							.preferred = fill_module_values[0],
							.values = fill_module_values,
							.annotations = NULL,
							.as_nested_settings = 1,
						},
						&fill_module, /* XXX: this isn't really of direct use now that it's a potentially full-blown settings string, see fill_module_settings */
						res_setting,
						res_desc);
	if (r)
		return r;

	/* hmm, we're about to assume this is always valid, so let's assert that's actually the case...
	 * looking at til_settings_get_and_describe_value() it looks to be optional there.
	 * TODO: since _we_ require the res_setting, we should provide a temporary place for it
	 * here if it's not guaranteed, then copy it into *res_setting if wanted.
	 */
	assert(res_setting && *res_setting);
	assert((*res_setting)->value_as_nested_settings);

	fill_module_settings = (*res_setting)->value_as_nested_settings;
	fill_module = til_settings_get_value_by_idx(fill_module_settings, 0, NULL);
	{
		if (strcasecmp(fill_module, "none")) {
			const til_module_t	*mod = til_lookup_module(fill_module);

			if (!mod)
				return -EINVAL;

			if (mod->setup) {
				r = mod->setup(fill_module_settings, res_setting, res_desc, NULL);
				if (r)
					return r;

				/* XXX: note no res_setup was provided, so while yes the fill_module_settings are
				 * fully populated according to the setup's return value, we don't yet have the baked
				 * setup.  That occurs below while baking the checkers res_setup.
				 */
			}
		}
	}
	/* TODO: here we would do nested setup for fill_module via (*res_setting)->settings until that returned 0.
	 * It seems like we would just leave res_setup NULL for nested setup at this phase, then in our if (res_setup)
	 * branch down below the nested setup would have to recur with res_setup supplied but pointing at a nested
	 * setup pointer hosted within this setup. */

	/* XXX but this is a little more complicated than simply performing exhaustive setup of the fill_module here.
	 * it's kind of like how in scripting languages you have two forms of interpolation while initializing variables;
	 * there's the immediate interpolation at the time of intialization, and there's the delayed interpolation at
	 * time of variable use.  i.e. foo="$a $b" vs. foo:="$a $b", the latter may expand $a and $b once and store the
	 * result in foo, whereas the former may just store the literal "$a $b" in foo and (re)perform the expansion of
	 * $a and $b every time $foo is evaluated.
	 *
	 * should every module have its own separate setting or snowflake syntax to control exhaustive setup up-front
	 * vs. just taking what settings have been provided and randomizing what's not provided at context create time?
	 * in the case of checkers::fill_module it's arguably less relevant (though the current frontends don't have a
	 * randomize settings feature, so if exhaustive setup of fill_module were forced up-front using the existing frontends
	 * would mean loss of fill_module randomized setup)  But that might be O.K. for something like checkers::fill_module
	 *
	 * where it becomes more relevant is something like rtv::channels, where the single rtv instance will repeatedly
	 * create+destroy channel contexts using the supplied (or omitted) settings.  We may want to have the settings
	 * exhaustively applied once when rtv was intantiated, giving the frontend setup opportunity to explicitly configure
	 * the channels exhaustively.  Or we may want to just partially specify some settings for the channels, and for
	 * the settings non-specified use the defaults OR for those unsepcified have them be randomized.  Then there's the
	 * question of should the randomizing recur for every channel switch or just occur once at time of rtv instantiation?
	 * 
	 * it feels like the module settings syntax should probably control this behavior in a general way so the modules don't
	 * start inventing their own approaches.  Perhaps the module name at the start of the settings string could simply have
	 * an optional leading modifier character from a reserved set module names can't start with.  Someting like %modulename
	 * for randomizing unspecified settings, : for evaluating settings just once up-front then reusing them, @modulename for
	 * accepting defaults for anything unspecified, and !modulename to fail if any settings aren't specified.  Maybe also
	 * something like * for making the current qualifiers apply recursively.
	 */

	r = til_settings_get_and_describe_value(settings,
						&(til_setting_spec_t){
							.name = "Checkers dynamics",
							.key = "dynamics",
							.preferred = dynamics_values[0],
							.values = dynamics_values,
							.annotations = NULL
						},
						&dynamics,
						res_setting,
						res_desc);
	if (r)
		return r;

	if (strcasecmp(dynamics, "odd") && strcasecmp(dynamics, "even")) {
		r = til_settings_get_and_describe_value(settings,
							&(til_setting_spec_t){
								.name = "Checkers dynamics rate",
								.key = "dynamics_rate",
								.preferred = dynamics_rate_values[0],
								.values = dynamics_rate_values,
								.annotations = NULL
							},
							&dynamics_rate,
							res_setting,
							res_desc);
		if (r)
			return r;
	}

	r = til_settings_get_and_describe_value(settings,
						&(til_setting_spec_t){
							.name = "Fill mode",
							.key = "fill",
							.preferred = fill_values[CHECKERS_DEFAULT_FILL],
							.values = fill_values,
							.annotations = NULL
						},
						&fill,
						res_setting,
						res_desc);
	if (r)
		return r;

	/* Even though sampled and textured fills don't neceesarily use the color,
	 * if there's no texture or no underlay to sample, we should have a color to fallback on.
	 */
	r = til_settings_get_and_describe_value(settings,
						&(til_setting_spec_t){
							.name = "Fill color",
							.key = "color",
							.preferred = TIL_SETTINGS_STR(CHECKERS_DEFAULT_COLOR),
							.random = checkers_random_color,
							.values = NULL,
							.annotations = NULL
						},
						&color,
						res_setting,
						res_desc);
	if (r)
		return r;

	if (res_setup) {
		checkers_setup_t	*setup;

		setup = til_setup_new(sizeof(*setup), checkers_setup_free);
		if (!setup)
			return -ENOMEM;

		sscanf(size, "%u", &setup->size);

		if (!strcasecmp(pattern, "checkered"))
			setup->pattern = CHECKERS_PATTERN_CHECKERED;
		else if (!strcasecmp(pattern, "random"))
			setup->pattern = CHECKERS_PATTERN_RANDOM;
		else {
			til_setup_free(&setup->til_setup);
			return -EINVAL;
		}

		if (strcasecmp(fill_module, "none")) {
			setup->fill_module = til_lookup_module(fill_module);
			if (!setup->fill_module) {
				til_setup_free(&setup->til_setup);
				return -ENOMEM;
			}

			if (setup->fill_module->setup) {
				r = setup->fill_module->setup(fill_module_settings, res_setting, res_desc, &setup->fill_module_setup);
				if (r) {
					til_setup_free(&setup->til_setup);
					return r;
				}
			}
		}

		if (!strcasecmp(dynamics, "odd"))
			setup->dynamics = CHECKERS_DYNAMICS_ODD;
		else if (!strcasecmp(dynamics, "even"))
			setup->dynamics = CHECKERS_DYNAMICS_EVEN;
		else if (!strcasecmp(dynamics, "alternating"))
			setup->dynamics = CHECKERS_DYNAMICS_ALTERNATING;
		else if (!strcasecmp(dynamics, "random"))
			setup->dynamics = CHECKERS_DYNAMICS_RANDOM;
		else {
			til_setup_free(&setup->til_setup);
			return -EINVAL;
		}

		if (setup->dynamics != CHECKERS_DYNAMICS_ODD && setup->dynamics != CHECKERS_DYNAMICS_EVEN)
			sscanf(dynamics_rate, "%f", &setup->rate);

		if (!strcasecmp(fill, "color"))
			setup->fill = CHECKERS_FILL_COLOR;
		else if (!strcasecmp(fill, "sampled"))
			setup->fill = CHECKERS_FILL_SAMPLED;
		else if (!strcasecmp(fill, "textured"))
			setup->fill = CHECKERS_FILL_TEXTURED;
		else if (!strcasecmp(fill, "random"))
			setup->fill = CHECKERS_FILL_RANDOM;
		else if (!strcasecmp(fill, "mixed"))
			setup->fill = CHECKERS_FILL_MIXED;
		else {
			til_setup_free(&setup->til_setup);
			return -EINVAL;
		}

		r = checkers_rgb_to_uint32(color, &setup->color);
		if (r < 0)
			return r;

		*res_setup = &setup->til_setup;
	}

	return 0;
}


til_module_t	checkers_module = {
	.create_context = checkers_create_context,
	.destroy_context = checkers_destroy_context,
	.prepare_frame = checkers_prepare_frame,
	.render_fragment = checkers_render_fragment,
	.setup = checkers_setup,
	.name = "checkers",
	.description = "Checker-patterned overlay (threaded)",
	.author = "Vito Caputo <vcaputo@pengaru.com>",
	.flags = TIL_MODULE_OVERLAYABLE,
};