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vsrc_mandelbrot.c
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1 /*
2  * Copyright (c) 2011 Michael Niedermayer
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  *
20  * The vsrc_color filter from Stefano Sabatini was used as template to create
21  * this
22  */
23 
24 /**
25  * @file
26  * Mandelbrot fraktal renderer
27  */
28 
29 #include "avfilter.h"
30 #include "formats.h"
31 #include "video.h"
32 #include "internal.h"
33 #include "libavutil/imgutils.h"
34 #include "libavutil/opt.h"
35 #include "libavutil/parseutils.h"
36 #include <float.h>
37 #include <math.h>
38 
39 #define SQR(a) ((a)*(a))
40 
41 enum Outer{
44 };
45 
46 enum Inner{
51 };
52 
53 typedef struct Point {
54  double p[2];
55  uint32_t val;
56 } Point;
57 
58 typedef struct {
59  const AVClass *class;
60  int w, h;
62  uint64_t pts;
63  char *rate;
64  int maxiter;
65  double start_x;
66  double start_y;
67  double start_scale;
68  double end_scale;
69  double end_pts;
70  double bailout;
71  enum Outer outer;
72  enum Inner inner;
77  double (*zyklus)[2];
78  uint32_t dither;
79 } MBContext;
80 
81 #define OFFSET(x) offsetof(MBContext, x)
82 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
83 
84 static const AVOption mandelbrot_options[] = {
85  {"size", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, CHAR_MIN, CHAR_MAX, FLAGS },
86  {"s", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, CHAR_MIN, CHAR_MAX, FLAGS },
87  {"rate", "set frame rate", OFFSET(rate), AV_OPT_TYPE_STRING, {.str="25"}, CHAR_MIN, CHAR_MAX, FLAGS },
88  {"r", "set frame rate", OFFSET(rate), AV_OPT_TYPE_STRING, {.str="25"}, CHAR_MIN, CHAR_MAX, FLAGS },
89  {"maxiter", "set max iterations number", OFFSET(maxiter), AV_OPT_TYPE_INT, {.i64=7189}, 1, INT_MAX, FLAGS },
90  {"start_x", "set the initial x position", OFFSET(start_x), AV_OPT_TYPE_DOUBLE, {.dbl=-0.743643887037158704752191506114774}, -100, 100, FLAGS },
91  {"start_y", "set the initial y position", OFFSET(start_y), AV_OPT_TYPE_DOUBLE, {.dbl=-0.131825904205311970493132056385139}, -100, 100, FLAGS },
92  {"start_scale", "set the initial scale value", OFFSET(start_scale), AV_OPT_TYPE_DOUBLE, {.dbl=3.0}, 0, FLT_MAX, FLAGS },
93  {"end_scale", "set the terminal scale value", OFFSET(end_scale), AV_OPT_TYPE_DOUBLE, {.dbl=0.3}, 0, FLT_MAX, FLAGS },
94  {"end_pts", "set the terminal pts value", OFFSET(end_pts), AV_OPT_TYPE_DOUBLE, {.dbl=400}, 0, INT64_MAX, FLAGS },
95  {"bailout", "set the bailout value", OFFSET(bailout), AV_OPT_TYPE_DOUBLE, {.dbl=10}, 0, FLT_MAX, FLAGS },
96 
97  {"outer", "set outer coloring mode", OFFSET(outer), AV_OPT_TYPE_INT, {.i64=NORMALIZED_ITERATION_COUNT}, 0, INT_MAX, FLAGS, "outer" },
98  {"iteration_count", "set iteration count mode", 0, AV_OPT_TYPE_CONST, {.i64=ITERATION_COUNT}, INT_MIN, INT_MAX, FLAGS, "outer" },
99  {"normalized_iteration_count", "set normalized iteration count mode", 0, AV_OPT_TYPE_CONST, {.i64=NORMALIZED_ITERATION_COUNT}, INT_MIN, INT_MAX, FLAGS, "outer" },
100 
101  {"inner", "set inner coloring mode", OFFSET(inner), AV_OPT_TYPE_INT, {.i64=MINCOL}, 0, INT_MAX, FLAGS, "inner" },
102  {"black", "set black mode", 0, AV_OPT_TYPE_CONST, {.i64=BLACK}, INT_MIN, INT_MAX, FLAGS, "inner"},
103  {"period", "set period mode", 0, AV_OPT_TYPE_CONST, {.i64=PERIOD}, INT_MIN, INT_MAX, FLAGS, "inner"},
104  {"convergence", "show time until convergence", 0, AV_OPT_TYPE_CONST, {.i64=CONVTIME}, INT_MIN, INT_MAX, FLAGS, "inner"},
105  {"mincol", "color based on point closest to the origin of the iterations", 0, AV_OPT_TYPE_CONST, {.i64=MINCOL}, INT_MIN, INT_MAX, FLAGS, "inner"},
106 
107  {NULL},
108 };
109 
110 AVFILTER_DEFINE_CLASS(mandelbrot);
111 
112 static av_cold int init(AVFilterContext *ctx, const char *args)
113 {
114  MBContext *mb = ctx->priv;
115  AVRational rate_q;
116  int err;
117 
118  mb->class = &mandelbrot_class;
120 
121  if ((err = (av_set_options_string(mb, args, "=", ":"))) < 0)
122  return err;
123  mb->bailout *= mb->bailout;
124 
125  mb->start_scale /=mb->h;
126  mb->end_scale /=mb->h;
127 
128  if (av_parse_video_rate(&rate_q, mb->rate) < 0) {
129  av_log(ctx, AV_LOG_ERROR, "Invalid frame rate: %s\n", mb->rate);
130  return AVERROR(EINVAL);
131  }
132  mb->time_base.num = rate_q.den;
133  mb->time_base.den = rate_q.num;
134 
135  mb->cache_allocated = mb->w * mb->h * 3;
136  mb->cache_used = 0;
137  mb->point_cache= av_malloc(sizeof(*mb->point_cache)*mb->cache_allocated);
138  mb-> next_cache= av_malloc(sizeof(*mb-> next_cache)*mb->cache_allocated);
139  mb-> zyklus = av_malloc(sizeof(*mb->zyklus) * (mb->maxiter+16));
140 
141  return 0;
142 }
143 
144 static av_cold void uninit(AVFilterContext *ctx)
145 {
146  MBContext *mb = ctx->priv;
147 
148  av_freep(&mb->rate);
149  av_freep(&mb->point_cache);
150  av_freep(&mb-> next_cache);
151  av_freep(&mb->zyklus);
152 }
153 
155 {
156  static const enum AVPixelFormat pix_fmts[] = {
159  };
160 
162  return 0;
163 }
164 
165 static int config_props(AVFilterLink *inlink)
166 {
167  AVFilterContext *ctx = inlink->src;
168  MBContext *mb = ctx->priv;
169 
170  if (av_image_check_size(mb->w, mb->h, 0, ctx) < 0)
171  return AVERROR(EINVAL);
172 
173  inlink->w = mb->w;
174  inlink->h = mb->h;
175  inlink->time_base = mb->time_base;
176 
177  return 0;
178 }
179 
180 static void fill_from_cache(AVFilterContext *ctx, uint32_t *color, int *in_cidx, int *out_cidx, double py, double scale){
181  MBContext *mb = ctx->priv;
182  for(; *in_cidx < mb->cache_used; (*in_cidx)++){
183  Point *p= &mb->point_cache[*in_cidx];
184  int x;
185  if(p->p[1] > py)
186  break;
187  x= round((p->p[0] - mb->start_x) / scale + mb->w/2);
188  if(x<0 || x >= mb->w)
189  continue;
190  if(color) color[x] = p->val;
191  if(out_cidx && *out_cidx < mb->cache_allocated)
192  mb->next_cache[(*out_cidx)++]= *p;
193  }
194 }
195 
196 static int interpol(MBContext *mb, uint32_t *color, int x, int y, int linesize)
197 {
198  uint32_t a,b,c,d, i;
199  uint32_t ipol=0xFF000000;
200  int dist;
201 
202  if(!x || !y || x+1==mb->w || y+1==mb->h)
203  return 0;
204 
205  dist= FFMAX(FFABS(x-(mb->w>>1))*mb->h, FFABS(y-(mb->h>>1))*mb->w);
206 
207  if(dist<(mb->w*mb->h>>3))
208  return 0;
209 
210  a=color[(x+1) + (y+0)*linesize];
211  b=color[(x-1) + (y+1)*linesize];
212  c=color[(x+0) + (y+1)*linesize];
213  d=color[(x+1) + (y+1)*linesize];
214 
215  if(a&&c){
216  b= color[(x-1) + (y+0)*linesize];
217  d= color[(x+0) + (y-1)*linesize];
218  }else if(b&&d){
219  a= color[(x+1) + (y-1)*linesize];
220  c= color[(x-1) + (y-1)*linesize];
221  }else if(c){
222  d= color[(x+0) + (y-1)*linesize];
223  a= color[(x-1) + (y+0)*linesize];
224  b= color[(x+1) + (y-1)*linesize];
225  }else if(d){
226  c= color[(x-1) + (y-1)*linesize];
227  a= color[(x-1) + (y+0)*linesize];
228  b= color[(x+1) + (y-1)*linesize];
229  }else
230  return 0;
231 
232  for(i=0; i<3; i++){
233  int s= 8*i;
234  uint8_t ac= a>>s;
235  uint8_t bc= b>>s;
236  uint8_t cc= c>>s;
237  uint8_t dc= d>>s;
238  int ipolab= (ac + bc);
239  int ipolcd= (cc + dc);
240  if(FFABS(ipolab - ipolcd) > 5)
241  return 0;
242  if(FFABS(ac-bc)+FFABS(cc-dc) > 20)
243  return 0;
244  ipol |= ((ipolab + ipolcd + 2)/4)<<s;
245  }
246  color[x + y*linesize]= ipol;
247  return 1;
248 }
249 
250 static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize, int64_t pts)
251 {
252  MBContext *mb = ctx->priv;
253  int x,y,i, in_cidx=0, next_cidx=0, tmp_cidx;
254  double scale= mb->start_scale*pow(mb->end_scale/mb->start_scale, pts/mb->end_pts);
255  int use_zyklus=0;
256  fill_from_cache(ctx, NULL, &in_cidx, NULL, mb->start_y+scale*(-mb->h/2-0.5), scale);
257  tmp_cidx= in_cidx;
258  memset(color, 0, sizeof(*color)*mb->w);
259  for(y=0; y<mb->h; y++){
260  int y1= y+1;
261  const double ci=mb->start_y+scale*(y-mb->h/2);
262  fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci, scale);
263  if(y1<mb->h){
264  memset(color+linesize*y1, 0, sizeof(*color)*mb->w);
265  fill_from_cache(ctx, color+linesize*y1, &tmp_cidx, NULL, ci + 3*scale/2, scale);
266  }
267 
268  for(x=0; x<mb->w; x++){
269  float av_uninit(epsilon);
270  const double cr=mb->start_x+scale*(x-mb->w/2);
271  double zr=cr;
272  double zi=ci;
273  uint32_t c=0;
274  double dv= mb->dither / (double)(1LL<<32);
275  mb->dither= mb->dither*1664525+1013904223;
276 
277  if(color[x + y*linesize] & 0xFF000000)
278  continue;
279  if(interpol(mb, color, x, y, linesize)){
280  if(next_cidx < mb->cache_allocated){
281  mb->next_cache[next_cidx ].p[0]= cr;
282  mb->next_cache[next_cidx ].p[1]= ci;
283  mb->next_cache[next_cidx++].val = color[x + y*linesize];
284  }
285  continue;
286  }
287 
288  use_zyklus= (x==0 || mb->inner!=BLACK ||color[x-1 + y*linesize] == 0xFF000000);
289  if(use_zyklus)
290  epsilon= scale*1*sqrt(SQR(x-mb->w/2) + SQR(y-mb->h/2))/mb->w;
291 
292 #define Z_Z2_C(outr,outi,inr,ini)\
293  outr= inr*inr - ini*ini + cr;\
294  outi= 2*inr*ini + ci;
295 
296 #define Z_Z2_C_ZYKLUS(outr,outi,inr,ini, Z)\
297  Z_Z2_C(outr,outi,inr,ini)\
298  if(use_zyklus){\
299  if(Z && fabs(mb->zyklus[i>>1][0]-outr)+fabs(mb->zyklus[i>>1][1]-outi) <= epsilon)\
300  break;\
301  }\
302  mb->zyklus[i][0]= outr;\
303  mb->zyklus[i][1]= outi;\
304 
305 
306 
307  for(i=0; i<mb->maxiter-8; i++){
308  double t;
309  Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
310  i++;
311  Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
312  i++;
313  Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
314  i++;
315  Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
316  i++;
317  Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
318  i++;
319  Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
320  i++;
321  Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
322  i++;
323  Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
324  if(zr*zr + zi*zi > mb->bailout){
325  i-= FFMIN(7, i);
326  for(; i<mb->maxiter; i++){
327  zr= mb->zyklus[i][0];
328  zi= mb->zyklus[i][1];
329  if(zr*zr + zi*zi > mb->bailout){
330  switch(mb->outer){
331  case ITERATION_COUNT: zr = i; break;
332  case NORMALIZED_ITERATION_COUNT: zr= i + log2(log(mb->bailout) / log(zr*zr + zi*zi)); break;
333  }
334  c= lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256;
335  break;
336  }
337  }
338  break;
339  }
340  }
341  if(!c){
342  if(mb->inner==PERIOD){
343  int j;
344  for(j=i-1; j; j--)
345  if(SQR(mb->zyklus[j][0]-zr) + SQR(mb->zyklus[j][1]-zi) < epsilon*epsilon*10)
346  break;
347  if(j){
348  c= i-j;
349  c= ((c<<5)&0xE0) + ((c<<10)&0xE000) + ((c<<15)&0xE00000);
350  }
351  }else if(mb->inner==CONVTIME){
352  c= floor(i*255.0/mb->maxiter+dv)*0x010101;
353  } else if(mb->inner==MINCOL){
354  int j;
355  double closest=9999;
356  int closest_index=0;
357  for(j=i-1; j>=0; j--)
358  if(SQR(mb->zyklus[j][0]) + SQR(mb->zyklus[j][1]) < closest){
359  closest= SQR(mb->zyklus[j][0]) + SQR(mb->zyklus[j][1]);
360  closest_index= j;
361  }
362  closest = sqrt(closest);
363  c= lrintf((mb->zyklus[closest_index][0]/closest+1)*127+dv) + lrintf((mb->zyklus[closest_index][1]/closest+1)*127+dv)*256;
364  }
365  }
366  c |= 0xFF000000;
367  color[x + y*linesize]= c;
368  if(next_cidx < mb->cache_allocated){
369  mb->next_cache[next_cidx ].p[0]= cr;
370  mb->next_cache[next_cidx ].p[1]= ci;
371  mb->next_cache[next_cidx++].val = c;
372  }
373  }
374  fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci + scale/2, scale);
375  }
376  FFSWAP(void*, mb->next_cache, mb->point_cache);
377  mb->cache_used = next_cidx;
378  if(mb->cache_used == mb->cache_allocated)
379  av_log(ctx, AV_LOG_INFO, "Mandelbrot cache is too small!\n");
380 }
381 
382 static int request_frame(AVFilterLink *link)
383 {
384  MBContext *mb = link->src->priv;
385  AVFilterBufferRef *picref = ff_get_video_buffer(link, AV_PERM_WRITE, mb->w, mb->h);
386  picref->video->sample_aspect_ratio = (AVRational) {1, 1};
387  picref->pts = mb->pts++;
388  picref->pos = -1;
389 
390  draw_mandelbrot(link->src, (uint32_t*)picref->data[0], picref->linesize[0]/4, picref->pts);
391  ff_filter_frame(link, picref);
392 
393  return 0;
394 }
395 
396 static const AVFilterPad mandelbrot_outputs[] = {
397  {
398  .name = "default",
399  .type = AVMEDIA_TYPE_VIDEO,
400  .request_frame = request_frame,
401  .config_props = config_props,
402  },
403  { NULL },
404 };
405 
407  .name = "mandelbrot",
408  .description = NULL_IF_CONFIG_SMALL("Render a Mandelbrot fractal."),
409 
410  .priv_size = sizeof(MBContext),
411  .init = init,
412  .uninit = uninit,
413 
415  .inputs = NULL,
416  .outputs = mandelbrot_outputs,
417  .priv_class = &mandelbrot_class,
418 };