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
424
425
426
427
428
429
430
431
432
|
#include <errno.h>
#include <float.h>
#include <stdlib.h>
#include <string.h>
#include "til.h"
#include "til_fb.h"
#include "til_module_context.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;
} 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;
unsigned recalc_needed:1;
} voronoi_distances_t;
typedef struct voronoi_context_t {
til_module_context_t til_module_context;
unsigned seed;
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
/* TODO: stuff like this makes me think there needs to be support for threaded prepare_frame(),
* since this could just have per-cpu lists of cells and per-cpu rand_r seeds which could make
* a significant difference for large numbers of cells.
*/
static void voronoi_randomize(voronoi_context_t *ctxt, int do_colors)
{
float inv_rand_max= 1.f / (float)RAND_MAX;
if (!do_colors) {
/* we can skip setting the colors when overlayed since they get sampled */
for (size_t i = 0; i < ctxt->setup->n_cells; i++) {
voronoi_cell_t *p = &ctxt->cells[i];
p->origin.x = ((float)rand_r(&ctxt->seed) * inv_rand_max) * 2.f - 1.f;
p->origin.y = ((float)rand_r(&ctxt->seed) * inv_rand_max) * 2.f - 1.f;
}
} else {
for (size_t i = 0; i < ctxt->setup->n_cells; i++) {
voronoi_cell_t *p = &ctxt->cells[i];
p->origin.x = ((float)rand_r(&ctxt->seed) * inv_rand_max) * 2.f - 1.f;
p->origin.y = ((float)rand_r(&ctxt->seed) * inv_rand_max) * 2.f - 1.f;
p->color = ((uint32_t)(rand_r(&ctxt->seed) % 256)) << 16;
p->color |= ((uint32_t)(rand_r(&ctxt->seed) % 256)) << 8;
p->color |= ((uint32_t)(rand_r(&ctxt->seed) % 256));
}
}
ctxt->distances.recalc_needed = 1;
}
static til_module_context_t * voronoi_create_context(const til_module_t *module, til_stream_t *stream, unsigned seed, unsigned ticks, unsigned n_cpus, char *path, til_setup_t *setup)
{
voronoi_context_t *ctxt;
ctxt = til_module_context_new(module, sizeof(voronoi_context_t) + ((voronoi_setup_t *)setup)->n_cells * sizeof(voronoi_cell_t), stream, seed, ticks, n_cpus, path, setup);
if (!ctxt)
return NULL;
ctxt->setup = (voronoi_setup_t *)setup;
ctxt->seed = seed;
voronoi_randomize(ctxt, 1);
return &ctxt->til_module_context;
}
static void voronoi_destroy_context(til_module_context_t *context)
{
voronoi_context_t *ctxt = (voronoi_context_t *)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 - 1);
y = (cell->origin.y * .5f + .5f) * (float)(ctxt->distances.height - 1);
return y * ctxt->distances.width + x;
}
static void voronoi_jumpfill_pass(voronoi_context_t *ctxt, v2f_t *db, v2f_t *ds, size_t step, const til_fb_fragment_t *fragment)
{
v2f_t dp = {};
dp.y = db->y;
for (int y = 0; y < fragment->height; y++, dp.y += ds->y) {
voronoi_distance_t *d = &ctxt->distances.buf[(fragment->y + y) * ctxt->distances.width + fragment->x];
dp.x = db->x;
for (int x = 0; x < fragment->width; x++, dp.x += ds->x, d++) {
voronoi_distance_t *dq;
if (d->cell && d->distance_sq == 0)
continue;
/* FIXME TODO: this almost certainly needs to use some atomics or at least more care in dereferencing dq->cell and
* writing to d->cell, since we perform jumpfill concurrently in render_fragment, and the step range deliberately
* puts us outside the current fragment's boundaries.
*/
#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 (fragment->x + x >= step) {
/* can sample to the left */
dq = d - step;
VORONOI_JUMPFILL;
if (fragment->y + y >= step) {
/* can sample above and to the left */
dq = d - step * ctxt->distances.width - step;
VORONOI_JUMPFILL;
}
if (fragment->frame_height - (fragment->y + y) > step) {
/* can sample below and to the left */
dq = d + step * ctxt->distances.width - step;
VORONOI_JUMPFILL;
}
}
if (fragment->frame_width - (fragment->x + x) > step) {
/* can sample to the right */
dq = d + step;
VORONOI_JUMPFILL;
if (fragment->y + y >= step) {
/* can sample above and to the right */
dq = d - step * ctxt->distances.width + step;
VORONOI_JUMPFILL;
}
if (fragment->frame_height - (fragment->y + y) > step) {
/* can sample below */
dq = d + step * ctxt->distances.width + step;
VORONOI_JUMPFILL;
}
}
if (fragment->y + y >= step) {
/* can sample above */
dq = d - step * ctxt->distances.width;
VORONOI_JUMPFILL;
}
if (fragment->frame_height - (fragment->y + y) > step) {
/* can sample below */
dq = d + step * ctxt->distances.width;
VORONOI_JUMPFILL;
}
}
}
}
/* distance calculating is split into two halves:
* 1. a serialized global/cell-oriented part, where the distances are wholesale
* reset then the "seeds" placed according to the cells.
* 2. a concurrent distance-oriented part, where per-pixel distances are computed
* within the bounds of the supplied fragment (tiled)
*
* These occur in prepare_pass/render_pass, respectively.
*/
static void voronoi_calculate_distances_prepare_pass(voronoi_context_t *ctxt)
{
memset(ctxt->distances.buf, 0, ctxt->distances.size * sizeof(*ctxt->distances.buf));
/* 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;
}
}
static void voronoi_calculate_distances_render_pass(voronoi_context_t *ctxt, const til_fb_fragment_t *fragment)
{
v2f_t ds = (v2f_t){
.x = 2.f / fragment->frame_width,
.y = 2.f / fragment->frame_height,
};
v2f_t db = (v2f_t){
.x = fragment->x * ds.x - 1.f,
.y = fragment->y * ds.y - 1.f,
};
/* An attempt at implementing https://en.wikipedia.org/wiki/Jump_flooding_algorithm */
/* now for every distance sample neighbors */
/* The step range still has to access the entire frame to ensure we can still find "seed" cells
* even when the current fragment/tile doesn't encompass any of them.
*
* i.e. if we strictly sampled within our fragment's bounds, we'd potentially not find a seed cell
* at all - epsecially in scenarios having small numbers of cells relative to the number of fragments/tiles.
*
* But aside from the potentially-missed-seed-cell bug, staying strictly without our fragment's
* boundaries for sampling also would result in clearly visible tile edges in the diagram.
*
* So no, we can't just treat every fragment as its own little isolated distances buf within the greater
* one. This does make it more complicated since outside our fragment's bounds other threads may be
* changing the cell pointers while we try dereference them. But all we really care about is finding
* seeds reliably, and those should already be populated in the prepare phase.
*/
for (size_t step = MAX(fragment->frame_width, fragment->frame_height) / 2; step > 0; step >>= 1)
voronoi_jumpfill_pass(ctxt, &db, &ds, step, fragment);
}
static void voronoi_sample_colors(voronoi_context_t *ctxt, const 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 - 1);
y = (p->origin.y * .5f + .5f) * (fragment->frame_height - 1);
p->color = fragment->buf[y * fragment->pitch + x];
}
}
static void voronoi_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)
{
voronoi_context_t *ctxt = (voronoi_context_t *)context;
til_fb_fragment_t *fragment = *fragment_ptr;
*res_frame_plan = (til_frame_plan_t){ .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);
ctxt->distances.recalc_needed = 1;
}
if (ctxt->setup->randomize)
voronoi_randomize(ctxt, !fragment->cleared);
/* if the fragment comes in already cleared/initialized, use it for the colors, producing a mosaic */
if (fragment->cleared)
voronoi_sample_colors(ctxt, fragment);
if (ctxt->distances.recalc_needed)
voronoi_calculate_distances_prepare_pass(ctxt);
}
static void voronoi_render_fragment(til_module_context_t *context, til_stream_t *stream, unsigned ticks, unsigned cpu, til_fb_fragment_t **fragment_ptr)
{
voronoi_context_t *ctxt = (voronoi_context_t *)context;
til_fb_fragment_t *fragment = *fragment_ptr;
if (ctxt->distances.recalc_needed)
voronoi_calculate_distances_render_pass(ctxt, fragment);
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 void 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;
}
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
};
int r;
r = til_settings_get_and_describe_value(settings,
&(til_setting_spec_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_spec_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;
if (res_setup) {
voronoi_setup_t *setup;
setup = til_setup_new(settings, sizeof(*setup), NULL);
if (!setup)
return -ENOMEM;
sscanf(n_cells, "%zu", &setup->n_cells);
if (!strcasecmp(randomize, "on"))
setup->randomize = 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,
.finish_frame = voronoi_finish_frame,
.setup = voronoi_setup,
.name = "voronoi",
.description = "Voronoi diagram (threaded)",
.author = "Vito Caputo <vcaputo@pengaru.com>",
.flags = TIL_MODULE_OVERLAYABLE,
};
|