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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{
46 };
47 
48 enum Inner{
53 };
54 
55 typedef struct Point {
56  double p[2];
57  uint32_t val;
58 } Point;
59 
60 typedef struct {
61  const AVClass *class;
62  int w, h;
64  uint64_t pts;
65  int maxiter;
66  double start_x;
67  double start_y;
68  double start_scale;
69  double end_scale;
70  double end_pts;
71  double bailout;
72  enum Outer outer;
73  enum Inner inner;
78  double (*zyklus)[2];
79  uint32_t dither;
80 
81  double morphxf;
82  double morphyf;
83  double morphamp;
84 } MBContext;
85 
86 #define OFFSET(x) offsetof(MBContext, x)
87 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
88 
89 static const AVOption mandelbrot_options[] = {
90  {"size", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, CHAR_MIN, CHAR_MAX, FLAGS },
91  {"s", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, CHAR_MIN, CHAR_MAX, FLAGS },
92  {"rate", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, CHAR_MIN, CHAR_MAX, FLAGS },
93  {"r", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, CHAR_MIN, CHAR_MAX, FLAGS },
94  {"maxiter", "set max iterations number", OFFSET(maxiter), AV_OPT_TYPE_INT, {.i64=7189}, 1, INT_MAX, FLAGS },
95  {"start_x", "set the initial x position", OFFSET(start_x), AV_OPT_TYPE_DOUBLE, {.dbl=-0.743643887037158704752191506114774}, -100, 100, FLAGS },
96  {"start_y", "set the initial y position", OFFSET(start_y), AV_OPT_TYPE_DOUBLE, {.dbl=-0.131825904205311970493132056385139}, -100, 100, FLAGS },
97  {"start_scale", "set the initial scale value", OFFSET(start_scale), AV_OPT_TYPE_DOUBLE, {.dbl=3.0}, 0, FLT_MAX, FLAGS },
98  {"end_scale", "set the terminal scale value", OFFSET(end_scale), AV_OPT_TYPE_DOUBLE, {.dbl=0.3}, 0, FLT_MAX, FLAGS },
99  {"end_pts", "set the terminal pts value", OFFSET(end_pts), AV_OPT_TYPE_DOUBLE, {.dbl=400}, 0, INT64_MAX, FLAGS },
100  {"bailout", "set the bailout value", OFFSET(bailout), AV_OPT_TYPE_DOUBLE, {.dbl=10}, 0, FLT_MAX, FLAGS },
101  {"morphxf", "set morph x frequency", OFFSET(morphxf), AV_OPT_TYPE_DOUBLE, {.dbl=0.01}, -FLT_MAX, FLT_MAX, FLAGS },
102  {"morphyf", "set morph y frequency", OFFSET(morphyf), AV_OPT_TYPE_DOUBLE, {.dbl=0.0123}, -FLT_MAX, FLT_MAX, FLAGS },
103  {"morphamp", "set morph amplitude", OFFSET(morphamp), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -FLT_MAX, FLT_MAX, FLAGS },
104 
105  {"outer", "set outer coloring mode", OFFSET(outer), AV_OPT_TYPE_INT, {.i64=NORMALIZED_ITERATION_COUNT}, 0, INT_MAX, FLAGS, "outer" },
106  {"iteration_count", "set iteration count mode", 0, AV_OPT_TYPE_CONST, {.i64=ITERATION_COUNT}, INT_MIN, INT_MAX, FLAGS, "outer" },
107  {"normalized_iteration_count", "set normalized iteration count mode", 0, AV_OPT_TYPE_CONST, {.i64=NORMALIZED_ITERATION_COUNT}, INT_MIN, INT_MAX, FLAGS, "outer" },
108  {"white", "set white mode", 0, AV_OPT_TYPE_CONST, {.i64=WHITE}, INT_MIN, INT_MAX, FLAGS, "outer" },
109  {"outz", "set outz mode", 0, AV_OPT_TYPE_CONST, {.i64=OUTZ}, INT_MIN, INT_MAX, FLAGS, "outer" },
110 
111  {"inner", "set inner coloring mode", OFFSET(inner), AV_OPT_TYPE_INT, {.i64=MINCOL}, 0, INT_MAX, FLAGS, "inner" },
112  {"black", "set black mode", 0, AV_OPT_TYPE_CONST, {.i64=BLACK}, INT_MIN, INT_MAX, FLAGS, "inner"},
113  {"period", "set period mode", 0, AV_OPT_TYPE_CONST, {.i64=PERIOD}, INT_MIN, INT_MAX, FLAGS, "inner"},
114  {"convergence", "show time until convergence", 0, AV_OPT_TYPE_CONST, {.i64=CONVTIME}, INT_MIN, INT_MAX, FLAGS, "inner"},
115  {"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"},
116 
117  {NULL},
118 };
119 
120 AVFILTER_DEFINE_CLASS(mandelbrot);
121 
122 static av_cold int init(AVFilterContext *ctx)
123 {
124  MBContext *mb = ctx->priv;
125 
126  mb->bailout *= mb->bailout;
127 
128  mb->start_scale /=mb->h;
129  mb->end_scale /=mb->h;
130 
131  mb->cache_allocated = mb->w * mb->h * 3;
132  mb->cache_used = 0;
133  mb->point_cache= av_malloc(sizeof(*mb->point_cache)*mb->cache_allocated);
134  mb-> next_cache= av_malloc(sizeof(*mb-> next_cache)*mb->cache_allocated);
135  mb-> zyklus = av_malloc(sizeof(*mb->zyklus) * (mb->maxiter+16));
136 
137  return 0;
138 }
139 
140 static av_cold void uninit(AVFilterContext *ctx)
141 {
142  MBContext *mb = ctx->priv;
143 
144  av_freep(&mb->point_cache);
145  av_freep(&mb-> next_cache);
146  av_freep(&mb->zyklus);
147 }
148 
150 {
151  static const enum AVPixelFormat pix_fmts[] = {
154  };
155 
157  return 0;
158 }
159 
160 static int config_props(AVFilterLink *inlink)
161 {
162  AVFilterContext *ctx = inlink->src;
163  MBContext *mb = ctx->priv;
164 
165  if (av_image_check_size(mb->w, mb->h, 0, ctx) < 0)
166  return AVERROR(EINVAL);
167 
168  inlink->w = mb->w;
169  inlink->h = mb->h;
170  inlink->time_base = av_inv_q(mb->frame_rate);
171 
172  return 0;
173 }
174 
175 static void fill_from_cache(AVFilterContext *ctx, uint32_t *color, int *in_cidx, int *out_cidx, double py, double scale){
176  MBContext *mb = ctx->priv;
177  if(mb->morphamp)
178  return;
179  for(; *in_cidx < mb->cache_used; (*in_cidx)++){
180  Point *p= &mb->point_cache[*in_cidx];
181  int x;
182  if(p->p[1] > py)
183  break;
184  x= round((p->p[0] - mb->start_x) / scale + mb->w/2);
185  if(x<0 || x >= mb->w)
186  continue;
187  if(color) color[x] = p->val;
188  if(out_cidx && *out_cidx < mb->cache_allocated)
189  mb->next_cache[(*out_cidx)++]= *p;
190  }
191 }
192 
193 static int interpol(MBContext *mb, uint32_t *color, int x, int y, int linesize)
194 {
195  uint32_t a,b,c,d, i;
196  uint32_t ipol=0xFF000000;
197  int dist;
198 
199  if(!x || !y || x+1==mb->w || y+1==mb->h)
200  return 0;
201 
202  dist= FFMAX(FFABS(x-(mb->w>>1))*mb->h, FFABS(y-(mb->h>>1))*mb->w);
203 
204  if(dist<(mb->w*mb->h>>3))
205  return 0;
206 
207  a=color[(x+1) + (y+0)*linesize];
208  b=color[(x-1) + (y+1)*linesize];
209  c=color[(x+0) + (y+1)*linesize];
210  d=color[(x+1) + (y+1)*linesize];
211 
212  if(a&&c){
213  b= color[(x-1) + (y+0)*linesize];
214  d= color[(x+0) + (y-1)*linesize];
215  }else if(b&&d){
216  a= color[(x+1) + (y-1)*linesize];
217  c= color[(x-1) + (y-1)*linesize];
218  }else if(c){
219  d= color[(x+0) + (y-1)*linesize];
220  a= color[(x-1) + (y+0)*linesize];
221  b= color[(x+1) + (y-1)*linesize];
222  }else if(d){
223  c= color[(x-1) + (y-1)*linesize];
224  a= color[(x-1) + (y+0)*linesize];
225  b= color[(x+1) + (y-1)*linesize];
226  }else
227  return 0;
228 
229  for(i=0; i<3; i++){
230  int s= 8*i;
231  uint8_t ac= a>>s;
232  uint8_t bc= b>>s;
233  uint8_t cc= c>>s;
234  uint8_t dc= d>>s;
235  int ipolab= (ac + bc);
236  int ipolcd= (cc + dc);
237  if(FFABS(ipolab - ipolcd) > 5)
238  return 0;
239  if(FFABS(ac-bc)+FFABS(cc-dc) > 20)
240  return 0;
241  ipol |= ((ipolab + ipolcd + 2)/4)<<s;
242  }
243  color[x + y*linesize]= ipol;
244  return 1;
245 }
246 
247 static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize, int64_t pts)
248 {
249  MBContext *mb = ctx->priv;
250  int x,y,i, in_cidx=0, next_cidx=0, tmp_cidx;
251  double scale= mb->start_scale*pow(mb->end_scale/mb->start_scale, pts/mb->end_pts);
252  int use_zyklus=0;
253  fill_from_cache(ctx, NULL, &in_cidx, NULL, mb->start_y+scale*(-mb->h/2-0.5), scale);
254  tmp_cidx= in_cidx;
255  memset(color, 0, sizeof(*color)*mb->w);
256  for(y=0; y<mb->h; y++){
257  int y1= y+1;
258  const double ci=mb->start_y+scale*(y-mb->h/2);
259  fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci, scale);
260  if(y1<mb->h){
261  memset(color+linesize*y1, 0, sizeof(*color)*mb->w);
262  fill_from_cache(ctx, color+linesize*y1, &tmp_cidx, NULL, ci + 3*scale/2, scale);
263  }
264 
265  for(x=0; x<mb->w; x++){
266  float av_uninit(epsilon);
267  const double cr=mb->start_x+scale*(x-mb->w/2);
268  double zr=cr;
269  double zi=ci;
270  uint32_t c=0;
271  double dv= mb->dither / (double)(1LL<<32);
272  mb->dither= mb->dither*1664525+1013904223;
273 
274  if(color[x + y*linesize] & 0xFF000000)
275  continue;
276  if(!mb->morphamp){
277  if(interpol(mb, color, x, y, linesize)){
278  if(next_cidx < mb->cache_allocated){
279  mb->next_cache[next_cidx ].p[0]= cr;
280  mb->next_cache[next_cidx ].p[1]= ci;
281  mb->next_cache[next_cidx++].val = color[x + y*linesize];
282  }
283  continue;
284  }
285  }else{
286  zr += cos(pts * mb->morphxf) * mb->morphamp;
287  zi += sin(pts * mb->morphyf) * mb->morphamp;
288  }
289 
290  use_zyklus= (x==0 || mb->inner!=BLACK ||color[x-1 + y*linesize] == 0xFF000000);
291  if(use_zyklus)
292  epsilon= scale*1*sqrt(SQR(x-mb->w/2) + SQR(y-mb->h/2))/mb->w;
293 
294 #define Z_Z2_C(outr,outi,inr,ini)\
295  outr= inr*inr - ini*ini + cr;\
296  outi= 2*inr*ini + ci;
297 
298 #define Z_Z2_C_ZYKLUS(outr,outi,inr,ini, Z)\
299  Z_Z2_C(outr,outi,inr,ini)\
300  if(use_zyklus){\
301  if(Z && fabs(mb->zyklus[i>>1][0]-outr)+fabs(mb->zyklus[i>>1][1]-outi) <= epsilon)\
302  break;\
303  }\
304  mb->zyklus[i][0]= outr;\
305  mb->zyklus[i][1]= outi;\
306 
307 
308 
309  for(i=0; i<mb->maxiter-8; i++){
310  double t;
311  Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
312  i++;
313  Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
314  i++;
315  Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
316  i++;
317  Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
318  i++;
319  Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
320  i++;
321  Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
322  i++;
323  Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
324  i++;
325  Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
326  if(zr*zr + zi*zi > mb->bailout){
327  i-= FFMIN(7, i);
328  for(; i<mb->maxiter; i++){
329  zr= mb->zyklus[i][0];
330  zi= mb->zyklus[i][1];
331  if(zr*zr + zi*zi > mb->bailout){
332  switch(mb->outer){
333  case ITERATION_COUNT:
334  zr = i;
335  c = lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256;
336  break;
338  zr = i + log2(log(mb->bailout) / log(zr*zr + zi*zi));
339  c = lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256;
340  break;
341  case WHITE:
342  c = 0xFFFFFF;
343  break;
344  case OUTZ:
345  zr /= mb->bailout;
346  zi /= mb->bailout;
347  c = (((int)(zr*128+128))&0xFF)*256 + (((int)(zi*128+128))&0xFF);
348  }
349  break;
350  }
351  }
352  break;
353  }
354  }
355  if(!c){
356  if(mb->inner==PERIOD){
357  int j;
358  for(j=i-1; j; j--)
359  if(SQR(mb->zyklus[j][0]-zr) + SQR(mb->zyklus[j][1]-zi) < epsilon*epsilon*10)
360  break;
361  if(j){
362  c= i-j;
363  c= ((c<<5)&0xE0) + ((c<<10)&0xE000) + ((c<<15)&0xE00000);
364  }
365  }else if(mb->inner==CONVTIME){
366  c= floor(i*255.0/mb->maxiter+dv)*0x010101;
367  } else if(mb->inner==MINCOL){
368  int j;
369  double closest=9999;
370  int closest_index=0;
371  for(j=i-1; j>=0; j--)
372  if(SQR(mb->zyklus[j][0]) + SQR(mb->zyklus[j][1]) < closest){
373  closest= SQR(mb->zyklus[j][0]) + SQR(mb->zyklus[j][1]);
374  closest_index= j;
375  }
376  closest = sqrt(closest);
377  c= lrintf((mb->zyklus[closest_index][0]/closest+1)*127+dv) + lrintf((mb->zyklus[closest_index][1]/closest+1)*127+dv)*256;
378  }
379  }
380  c |= 0xFF000000;
381  color[x + y*linesize]= c;
382  if(next_cidx < mb->cache_allocated){
383  mb->next_cache[next_cidx ].p[0]= cr;
384  mb->next_cache[next_cidx ].p[1]= ci;
385  mb->next_cache[next_cidx++].val = c;
386  }
387  }
388  fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci + scale/2, scale);
389  }
390  FFSWAP(void*, mb->next_cache, mb->point_cache);
391  mb->cache_used = next_cidx;
392  if(mb->cache_used == mb->cache_allocated)
393  av_log(ctx, AV_LOG_INFO, "Mandelbrot cache is too small!\n");
394 }
395 
396 static int request_frame(AVFilterLink *link)
397 {
398  MBContext *mb = link->src->priv;
399  AVFrame *picref = ff_get_video_buffer(link, mb->w, mb->h);
400  if (!picref)
401  return AVERROR(ENOMEM);
402 
403  picref->sample_aspect_ratio = (AVRational) {1, 1};
404  picref->pts = mb->pts++;
405 
406  draw_mandelbrot(link->src, (uint32_t*)picref->data[0], picref->linesize[0]/4, picref->pts);
407  return ff_filter_frame(link, picref);
408 }
409 
410 static const AVFilterPad mandelbrot_outputs[] = {
411  {
412  .name = "default",
413  .type = AVMEDIA_TYPE_VIDEO,
414  .request_frame = request_frame,
415  .config_props = config_props,
416  },
417  { NULL }
418 };
419 
421  .name = "mandelbrot",
422  .description = NULL_IF_CONFIG_SMALL("Render a Mandelbrot fractal."),
423  .priv_size = sizeof(MBContext),
424  .priv_class = &mandelbrot_class,
425  .init = init,
426  .uninit = uninit,
428  .inputs = NULL,
429  .outputs = mandelbrot_outputs,
430 };