summaryrefslogtreecommitdiff
path: root/src/modules/voronoi/voronoi.c
blob: ea90389a11bd43b982e042a121f4b978bb9a713d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
#include <errno.h>
#include <float.h>
#include <stdlib.h>
#include <string.h>

#include "til.h"
#include "til_fb.h"
#include "til_util.h"

#include "v2f.h"

/* Rudimentary Voronoi diagram module:
 * https://en.wikipedia.org/wiki/Voronoi_diagram
 *
 * When used as an overlay, the output fragment's contents are sampled for
 * coloring the cells producing a realtime mosaic style effect.
 */

/* Copyright (C) 2022 Vito Caputo <vcaputo@pengaru.com> */

typedef struct voronoi_setup_t {
	til_setup_t		til_setup;
	size_t			n_cells;
	unsigned		randomize:1;
	unsigned		dirty:1;
} voronoi_setup_t;

typedef struct voronoi_cell_t {
	v2f_t			origin;
	uint32_t		color;
} voronoi_cell_t;

typedef struct voronoi_distance_t {
	voronoi_cell_t		*cell;
	float			distance_sq;
} voronoi_distance_t;

typedef struct voronoi_distances_t {
	int			width, height;
	size_t			size;
	voronoi_distance_t	*buf;
} voronoi_distances_t;

typedef struct voronoi_context_t {
	voronoi_setup_t		setup;
	voronoi_distances_t	distances;
	voronoi_cell_t		cells[];
} voronoi_context_t;


#define VORONOI_DEFAULT_N_CELLS		1024
#define VORONOI_DEFAULT_DIRTY		0
#define VORONOI_DEFAULT_RANDOMIZE	0


static voronoi_setup_t voronoi_default_setup = {
	.n_cells = VORONOI_DEFAULT_N_CELLS,
	.dirty = VORONOI_DEFAULT_DIRTY,
	.randomize = VORONOI_DEFAULT_RANDOMIZE,
};


static void voronoi_randomize(voronoi_context_t *ctxt)
{
	float	inv_rand_max= 1.f / (float)RAND_MAX;

	for (size_t i = 0; i < ctxt->setup.n_cells; i++) {
		voronoi_cell_t	*p = &ctxt->cells[i];

		p->origin.x = ((float)rand() * inv_rand_max) * 2.f - 1.f;
		p->origin.y = ((float)rand() * inv_rand_max) * 2.f - 1.f;

		p->color = ((uint32_t)(rand() % 256)) << 16;
		p->color |= ((uint32_t)(rand() % 256)) << 8;
		p->color |= ((uint32_t)(rand() % 256));
	}
}


static void * voronoi_create_context(unsigned ticks, unsigned n_cpus, til_setup_t *setup)
{
	voronoi_context_t	*ctxt;

	if (!setup)
		setup = &voronoi_default_setup.til_setup;

	ctxt = calloc(1, sizeof(voronoi_context_t) + ((voronoi_setup_t *)setup)->n_cells * sizeof(voronoi_cell_t));
	if (!ctxt)
		return NULL;

	ctxt->setup = *(voronoi_setup_t *)setup;

	voronoi_randomize(ctxt);

	return ctxt;
}


static void voronoi_destroy_context(void *context)
{
	voronoi_context_t	*ctxt = context;

	free(ctxt->distances.buf);
	free(ctxt);
}


static inline size_t voronoi_cell_origin_to_distance_idx(const voronoi_context_t *ctxt, const voronoi_cell_t *cell)
{
	size_t	x, y;

	x = (cell->origin.x * .5f + .5f) * (float)ctxt->distances.width;
	y = (cell->origin.y * .5f + .5f) * (float)ctxt->distances.height;

	return y * ctxt->distances.width + x;
}


static void voronoi_jumpfill_pass(voronoi_context_t *ctxt, v2f_t *ds, size_t step)
{
	voronoi_distance_t	*d = ctxt->distances.buf;
	v2f_t			dp = {};

	dp.y = -1.f;
	for (int y = 0; y < ctxt->distances.height; y++, dp.y += ds->y) {

		dp.x = -1.f;
		for (int x = 0; x < ctxt->distances.width; x++, dp.x += ds->x, d++) {
			voronoi_distance_t	*dq;

			if (d->cell && d->distance_sq == 0)
				continue;

#define VORONOI_JUMPFILL																	\
				if (dq->cell) {														\
					float	dist_sq = v2f_distance_sq(&dq->cell->origin, &dp);							\
																			\
					if (!d->cell) { /* we're unassigned, just join dq's cell */							\
						d->cell = dq->cell;											\
						d->distance_sq = dist_sq;										\
					} else if (dist_sq < d->distance_sq) { /* is dq's cell's origin closer than the present one?  then join it */	\
						d->cell = dq->cell;											\
						d->distance_sq = dist_sq;										\
					}														\
				}

			if (x >= step) {
				/* can sample to the left */
				dq = d - step;

				VORONOI_JUMPFILL;

				if (y >= step) {
					/* can sample above and to the left */
					dq = d - step * ctxt->distances.width - step;

					VORONOI_JUMPFILL;
				}

				if (ctxt->distances.height - y > step) {
					/* can sample below and to the left */
					dq = d + step * ctxt->distances.width - step;

					VORONOI_JUMPFILL;
				}

			}

			if (ctxt->distances.width - x > step) {
				/* can sample to the right */
				dq = d + step;

				VORONOI_JUMPFILL;

				if (y >= step) {
					/* can sample above and to the right */
					dq = d - step * ctxt->distances.width + step;

					VORONOI_JUMPFILL;
				}

				if (ctxt->distances.height - y > step) {
					/* can sample below */
					dq = d + step * ctxt->distances.width + step;

					VORONOI_JUMPFILL;
				}
			}

			if (y >= step) {
				/* can sample above */
				dq = d - step * ctxt->distances.width;

				VORONOI_JUMPFILL;
			}

			if (ctxt->distances.height - y > step) {
				/* can sample below */
				dq = d + step * ctxt->distances.width;

				VORONOI_JUMPFILL;
			}
		}
	}
}


static void voronoi_calculate_distances(voronoi_context_t *ctxt)
{
	v2f_t	ds = (v2f_t){
			.x = 2.f / ctxt->distances.width,
			.y = 2.f / ctxt->distances.height,
		};

	memset(ctxt->distances.buf, 0, ctxt->distances.size * sizeof(*ctxt->distances.buf));

#if 0
	/* naive inefficient brute-force but correct algorithm */
	for (size_t i = 0; i < ctxt->setup.n_cells; i++) {
		voronoi_distance_t	*d = ctxt->distances.buf;
		v2f_t			dp = {};

		dp.y = -1.f;
		for (int y = 0; y < ctxt->distances.height; y++, dp.y += ds.y) {

			dp.x = -1.f;
			for (int x = 0; x < ctxt->distances.width; x++, dp.x += ds.x, d++) {
				float	dist_sq;

				dist_sq = v2f_distance_sq(&ctxt->cells[i].origin, &dp);
				if (!d->cell || dist_sq < d->distance_sq) {
					d->cell = &ctxt->cells[i];
					d->distance_sq = dist_sq;
				}
			}
		}
	}
#else
	/* An attempt at implementing https://en.wikipedia.org/wiki/Jump_flooding_algorithm */

	/* first assign the obvious zero-distance cell origins */
	for (size_t i = 0; i < ctxt->setup.n_cells; i++) {
		voronoi_cell_t		*c = &ctxt->cells[i];
		size_t			idx;
		voronoi_distance_t	*d;

		idx = voronoi_cell_origin_to_distance_idx(ctxt, c);
		d = &ctxt->distances.buf[idx];

		d->cell = c;
		d->distance_sq = 0.f;
	}

	/* now for every distance sample neighbors */
	if (ctxt->setup.dirty) {
		for (size_t step = 2; step <= MAX(ctxt->distances.width, ctxt->distances.height); step *= 2)
			voronoi_jumpfill_pass(ctxt, &ds, step);
	} else {
		for (size_t step = MAX(ctxt->distances.width, ctxt->distances.height) / 2; step > 0; step >>= 1)
			voronoi_jumpfill_pass(ctxt, &ds, step);
	}
#endif
}


static void voronoi_sample_colors(voronoi_context_t *ctxt, til_fb_fragment_t *fragment)
{
	for (size_t i = 0; i < ctxt->setup.n_cells; i++) {
		voronoi_cell_t	*p = &ctxt->cells[i];
		int		x, y;

		x = (p->origin.x * .5f + .5f) * fragment->frame_width;
		y = (p->origin.y * .5f + .5f) * fragment->frame_height;

		p->color = fragment->buf[y * fragment->pitch + x];
	}
}


static void voronoi_prepare_frame(void *context, unsigned ticks, unsigned n_cpus, til_fb_fragment_t *fragment, til_fragmenter_t *res_fragmenter)
{
	voronoi_context_t	*ctxt = context;

	*res_fragmenter = til_fragmenter_tile64;

	if (!ctxt->distances.buf ||
	    ctxt->distances.width != fragment->frame_width ||
	    ctxt->distances.height != fragment->frame_height) {

		free(ctxt->distances.buf);
		ctxt->distances.width = fragment->frame_width;
		ctxt->distances.height = fragment->frame_height;
		ctxt->distances.size = fragment->frame_width * fragment->frame_height;
		ctxt->distances.buf = malloc(sizeof(voronoi_distance_t) * ctxt->distances.size);

		if (!ctxt->setup.randomize)
			voronoi_calculate_distances(ctxt);
	}

	/* TODO: explore moving voronoi_calculate_distances() into render_fragment (threaded) */

	if (ctxt->setup.randomize) {
		voronoi_randomize(ctxt);
		voronoi_calculate_distances(ctxt);
	}

	/* if the fragment comes in already cleared/initialized, use it for the colors, producing a mosaic */
	if (fragment->cleared)
		voronoi_sample_colors(ctxt, fragment);
}


static void voronoi_render_fragment(void *context, unsigned ticks, unsigned cpu, til_fb_fragment_t *fragment)
{
	voronoi_context_t	*ctxt = context;

	for (int y = 0; y < fragment->height; y++) {
		for (int x = 0; x < fragment->width; x++) {
			fragment->buf[y * fragment->pitch + x] = ctxt->distances.buf[(y + fragment->y) * ctxt->distances.width + (fragment->x + x)].cell->color;
		}
	}
}


static int voronoi_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	*n_cells;
	const char	*n_cells_values[] = {
				"512",
				"1024",
				"2048",
				"4096",
				"8192",
				"16384",
				"32768",
				NULL
			};
	const char	*randomize;
	const char	*bool_values[] = {
				"off",
				"on",
				NULL
			};
	const char	*dirty;
	int		r;

	r = til_settings_get_and_describe_value(settings,
						&(til_setting_desc_t){
							.name = "Voronoi cells quantity",
							.key = "cells",
							.regex = "^[0-9]+",
							.preferred = TIL_SETTINGS_STR(VORONOI_DEFAULT_N_CELLS),
							.values = n_cells_values,
							.annotations = NULL
						},
						&n_cells,
						res_setting,
						res_desc);
	if (r)
		return r;

	r = til_settings_get_and_describe_value(settings,
						&(til_setting_desc_t){
							.name = "Constantly randomize cell placement",
							.key = "randomize",
							.regex = "^(on|off)",
							.preferred = bool_values[VORONOI_DEFAULT_RANDOMIZE],
							.values = bool_values,
							.annotations = NULL
						},
						&randomize,
						res_setting,
						res_desc);
	if (r)
		return r;

	r = til_settings_get_and_describe_value(settings,
						&(til_setting_desc_t){
							.name = "Use faster, imperfect method",
							.key = "dirty",
							.regex = "^(on|off)",
							.preferred = bool_values[VORONOI_DEFAULT_DIRTY],
							.values = bool_values,
							.annotations = NULL
						},
						&dirty,
						res_setting,
						res_desc);
	if (r)
		return r;

	if (res_setup) {
		voronoi_setup_t	*setup;

		setup = til_setup_new(sizeof(*setup), (void(*)(til_setup_t *))free);
		if (!setup)
			return -ENOMEM;

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

		if (!strcasecmp(randomize, "on"))
			setup->randomize = 1;

		if (!strcasecmp(dirty, "on"))
			setup->dirty = 1;

		*res_setup = &setup->til_setup;
	}
	return 0;
}


til_module_t	voronoi_module = {
	.create_context = voronoi_create_context,
	.destroy_context = voronoi_destroy_context,
	.prepare_frame = voronoi_prepare_frame,
	.render_fragment = voronoi_render_fragment,
	.setup = voronoi_setup,
	.name = "voronoi",
	.description = "Voronoi diagram",
	.author = "Vito Caputo <vcaputo@pengaru.com>",
	.flags = TIL_MODULE_OVERLAYABLE,
};
© All Rights Reserved