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libavfilter/vsrc_mandelbrot.c

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00001 /*
00002  * Copyright (c) 2011 Michael Niedermayer
00003  *
00004  * This file is part of FFmpeg.
00005  *
00006  * FFmpeg is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU Lesser General Public
00008  * License as published by the Free Software Foundation; either
00009  * version 2.1 of the License, or (at your option) any later version.
00010  *
00011  * FFmpeg is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014  * Lesser General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU Lesser General Public
00017  * License along with FFmpeg; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00019  *
00020  * The vsrc_color filter from Stefano Sabatini was used as template to create
00021  * this
00022  */
00023 
00029 #include "avfilter.h"
00030 #include "libavutil/imgutils.h"
00031 #include "libavutil/opt.h"
00032 #include "libavutil/parseutils.h"
00033 #include <float.h>
00034 #include <math.h>
00035 
00036 #define SQR(a) ((a)*(a))
00037 
00038 enum Outer{
00039     ITERATION_COUNT,
00040     NORMALIZED_ITERATION_COUNT,
00041 };
00042 
00043 enum Inner{
00044     BLACK,
00045     PERIOD,
00046     CONVTIME,
00047     MINCOL,
00048 };
00049 
00050 typedef struct Point {
00051     double p[2];
00052     uint32_t val;
00053 } Point;
00054 
00055 typedef struct {
00056     const AVClass *class;
00057     int w, h;
00058     AVRational time_base;
00059     uint64_t pts;
00060     char *size, *rate;
00061     int maxiter;
00062     double start_x;
00063     double start_y;
00064     double start_scale;
00065     double end_scale;
00066     double end_pts;
00067     double bailout;
00068     enum Outer outer;
00069     enum Inner inner;
00070     int cache_allocated;
00071     int cache_used;
00072     Point *point_cache;
00073     Point *next_cache;
00074     double (*zyklus)[2];
00075     uint32_t dither;
00076 } MBContext;
00077 
00078 #define OFFSET(x) offsetof(MBContext, x)
00079 
00080 static const AVOption mandelbrot_options[] = {
00081     {"size",        "set frame size",                OFFSET(size),    AV_OPT_TYPE_STRING,     {.str="640x480"},  CHAR_MIN, CHAR_MAX },
00082     {"s",           "set frame size",                OFFSET(size),    AV_OPT_TYPE_STRING,     {.str="640x480"},  CHAR_MIN, CHAR_MAX },
00083     {"rate",        "set frame rate",                OFFSET(rate),    AV_OPT_TYPE_STRING,     {.str="25"},  CHAR_MIN, CHAR_MAX },
00084     {"r",           "set frame rate",                OFFSET(rate),    AV_OPT_TYPE_STRING,     {.str="25"},  CHAR_MIN, CHAR_MAX },
00085     {"maxiter",     "set max iterations number",     OFFSET(maxiter), AV_OPT_TYPE_INT,        {.dbl=7189},  1,        INT_MAX  },
00086     {"start_x",     "set the initial x position",    OFFSET(start_x), AV_OPT_TYPE_DOUBLE,     {.dbl=-0.743643887037158704752191506114774}, -100, 100  },
00087     {"start_y",     "set the initial y position",    OFFSET(start_y), AV_OPT_TYPE_DOUBLE,     {.dbl=-0.131825904205311970493132056385139}, -100, 100  },
00088     {"start_scale", "set the initial scale value",   OFFSET(start_scale), AV_OPT_TYPE_DOUBLE, {.dbl=3.0},  0, FLT_MAX },
00089     {"end_scale",   "set the terminal scale value",  OFFSET(end_scale), AV_OPT_TYPE_DOUBLE,   {.dbl=0.3},  0, FLT_MAX },
00090     {"end_pts",     "set the terminal pts value",    OFFSET(end_pts), AV_OPT_TYPE_DOUBLE,     {.dbl=400},  0, INT64_MAX },
00091     {"bailout",     "set the bailout value",         OFFSET(bailout), AV_OPT_TYPE_DOUBLE,     {.dbl=10},   0, FLT_MAX },
00092 
00093     {"outer",       "set outer coloring mode",       OFFSET(outer), AV_OPT_TYPE_INT, {.dbl=NORMALIZED_ITERATION_COUNT}, 0, INT_MAX, 0, "outer"},
00094     {"iteration_count", "set iteration count mode",  0, AV_OPT_TYPE_CONST, {.dbl=ITERATION_COUNT}, INT_MIN, INT_MAX, 0, "outer" },
00095     {"normalized_iteration_count", "set normalized iteration count mode",   0, AV_OPT_TYPE_CONST, {.dbl=NORMALIZED_ITERATION_COUNT}, INT_MIN, INT_MAX, 0, "outer" },
00096 
00097     {"inner",       "set inner coloring mode",       OFFSET(inner), AV_OPT_TYPE_INT, {.dbl=MINCOL}, 0, INT_MAX, 0, "inner"},
00098     {"black",       "set black mode",                0, AV_OPT_TYPE_CONST, {.dbl=BLACK}, INT_MIN, INT_MAX, 0, "inner" },
00099     {"period",      "set period mode",               0, AV_OPT_TYPE_CONST, {.dbl=PERIOD}, INT_MIN, INT_MAX, 0, "inner" },
00100     {"convergence", "show time until convergence",   0, AV_OPT_TYPE_CONST, {.dbl=CONVTIME}, INT_MIN, INT_MAX, 0, "inner" },
00101     {"mincol",      "color based on point closest to the origin of the iterations",   0, AV_OPT_TYPE_CONST, {.dbl=MINCOL}, INT_MIN, INT_MAX, 0, "inner" },
00102 
00103     {NULL},
00104 };
00105 
00106 static const char *mandelbrot_get_name(void *ctx)
00107 {
00108     return "mandelbrot";
00109 }
00110 
00111 static const AVClass mandelbrot_class = {
00112     "MBContext",
00113     mandelbrot_get_name,
00114     mandelbrot_options
00115 };
00116 
00117 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00118 {
00119     MBContext *mb = ctx->priv;
00120     AVRational rate_q;
00121     int err;
00122 
00123     mb->class = &mandelbrot_class;
00124     av_opt_set_defaults(mb);
00125 
00126     if ((err = (av_set_options_string(mb, args, "=", ":"))) < 0) {
00127         av_log(ctx, AV_LOG_ERROR, "Error parsing options string: '%s'\n", args);
00128         return err;
00129     }
00130     mb->bailout *= mb->bailout;
00131 
00132     if (av_parse_video_size(&mb->w, &mb->h, mb->size) < 0) {
00133         av_log(ctx, AV_LOG_ERROR, "Invalid frame size: %s\n", mb->size);
00134         return AVERROR(EINVAL);
00135     }
00136     mb->start_scale /=mb->h;
00137     mb->end_scale /=mb->h;
00138 
00139     if (av_parse_video_rate(&rate_q, mb->rate) < 0 ||
00140         rate_q.den <= 0 || rate_q.num <= 0) {
00141         av_log(ctx, AV_LOG_ERROR, "Invalid frame rate: %s\n", mb->rate);
00142         return AVERROR(EINVAL);
00143     }
00144     mb->time_base.num = rate_q.den;
00145     mb->time_base.den = rate_q.num;
00146 
00147     mb->cache_allocated = mb->w * mb->h * 3;
00148     mb->cache_used = 0;
00149     mb->point_cache= av_malloc(sizeof(*mb->point_cache)*mb->cache_allocated);
00150     mb-> next_cache= av_malloc(sizeof(*mb-> next_cache)*mb->cache_allocated);
00151     mb-> zyklus    = av_malloc(sizeof(*mb->zyklus) * (mb->maxiter+16));
00152 
00153     return 0;
00154 }
00155 
00156 static av_cold void uninit(AVFilterContext *ctx)
00157 {
00158     MBContext *mb = ctx->priv;
00159 
00160     av_freep(&mb->size);
00161     av_freep(&mb->rate);
00162     av_freep(&mb->point_cache);
00163     av_freep(&mb-> next_cache);
00164     av_freep(&mb->zyklus);
00165 }
00166 
00167 static int query_formats(AVFilterContext *ctx)
00168 {
00169     static const enum PixelFormat pix_fmts[] = {
00170         PIX_FMT_BGR32,
00171         PIX_FMT_NONE
00172     };
00173 
00174     avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
00175     return 0;
00176 }
00177 
00178 static int config_props(AVFilterLink *inlink)
00179 {
00180     AVFilterContext *ctx = inlink->src;
00181     MBContext *mb = ctx->priv;
00182 
00183     if (av_image_check_size(mb->w, mb->h, 0, ctx) < 0)
00184         return AVERROR(EINVAL);
00185 
00186     inlink->w = mb->w;
00187     inlink->h = mb->h;
00188     inlink->time_base = mb->time_base;
00189 
00190     return 0;
00191 }
00192 
00193 static void fill_from_cache(AVFilterContext *ctx, uint32_t *color, int *in_cidx, int *out_cidx, double py, double scale){
00194     MBContext *mb = ctx->priv;
00195     for(; *in_cidx < mb->cache_used; (*in_cidx)++){
00196         Point *p= &mb->point_cache[*in_cidx];
00197         int x;
00198         if(p->p[1] > py)
00199             break;
00200         x= round((p->p[0] - mb->start_x) / scale + mb->w/2);
00201         if(x<0 || x >= mb->w)
00202             continue;
00203         if(color) color[x] = p->val;
00204         if(out_cidx && *out_cidx < mb->cache_allocated)
00205             mb->next_cache[(*out_cidx)++]= *p;
00206     }
00207 }
00208 
00209 static int interpol(MBContext *mb, uint32_t *color, int x, int y, int linesize)
00210 {
00211     uint32_t a,b,c,d, i;
00212     uint32_t ipol=0xFF000000;
00213     int dist;
00214 
00215     if(!x || !y || x+1==mb->w || y+1==mb->h)
00216         return 0;
00217 
00218     dist= FFMAX(FFABS(x-(mb->w>>1))*mb->h, FFABS(y-(mb->h>>1))*mb->w);
00219 
00220     if(dist<(mb->w*mb->h>>3))
00221         return 0;
00222 
00223     a=color[(x+1) + (y+0)*linesize];
00224     b=color[(x-1) + (y+1)*linesize];
00225     c=color[(x+0) + (y+1)*linesize];
00226     d=color[(x+1) + (y+1)*linesize];
00227 
00228     if(a&&c){
00229         b= color[(x-1) + (y+0)*linesize];
00230         d= color[(x+0) + (y-1)*linesize];
00231     }else if(b&&d){
00232         a= color[(x+1) + (y-1)*linesize];
00233         c= color[(x-1) + (y-1)*linesize];
00234     }else if(c){
00235         d= color[(x+0) + (y-1)*linesize];
00236         a= color[(x-1) + (y+0)*linesize];
00237         b= color[(x+1) + (y-1)*linesize];
00238     }else if(d){
00239         c= color[(x-1) + (y-1)*linesize];
00240         a= color[(x-1) + (y+0)*linesize];
00241         b= color[(x+1) + (y-1)*linesize];
00242     }else
00243         return 0;
00244 
00245     for(i=0; i<3; i++){
00246         int s= 8*i;
00247         uint8_t ac= a>>s;
00248         uint8_t bc= b>>s;
00249         uint8_t cc= c>>s;
00250         uint8_t dc= d>>s;
00251         int ipolab= (ac + bc);
00252         int ipolcd= (cc + dc);
00253         if(FFABS(ipolab - ipolcd) > 5)
00254             return 0;
00255         if(FFABS(ac-bc)+FFABS(cc-dc) > 20)
00256             return 0;
00257         ipol |= ((ipolab + ipolcd + 2)/4)<<s;
00258     }
00259     color[x + y*linesize]= ipol;
00260     return 1;
00261 }
00262 
00263 static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize, int64_t pts)
00264 {
00265     MBContext *mb = ctx->priv;
00266     int x,y,i, in_cidx=0, next_cidx=0, tmp_cidx;
00267     double scale= mb->start_scale*pow(mb->end_scale/mb->start_scale, pts/mb->end_pts);
00268     int use_zyklus=0;
00269     fill_from_cache(ctx, NULL, &in_cidx, NULL, mb->start_y+scale*(-mb->h/2-0.5), scale);
00270     tmp_cidx= in_cidx;
00271     memset(color, 0, sizeof(*color)*mb->w);
00272     for(y=0; y<mb->h; y++){
00273         int y1= y+1;
00274         const double ci=mb->start_y+scale*(y-mb->h/2);
00275         fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci, scale);
00276         if(y1<mb->h){
00277             memset(color+linesize*y1, 0, sizeof(*color)*mb->w);
00278             fill_from_cache(ctx, color+linesize*y1, &tmp_cidx, NULL, ci + 3*scale/2, scale);
00279         }
00280 
00281         for(x=0; x<mb->w; x++){
00282             float av_uninit(epsilon);
00283             const double cr=mb->start_x+scale*(x-mb->w/2);
00284             double zr=cr;
00285             double zi=ci;
00286             uint32_t c=0;
00287             double dv= mb->dither / (double)(1LL<<32);
00288             mb->dither= mb->dither*1664525+1013904223;
00289 
00290             if(color[x + y*linesize] & 0xFF000000)
00291                 continue;
00292             if(interpol(mb, color, x, y, linesize)){
00293                 if(next_cidx < mb->cache_allocated){
00294                     mb->next_cache[next_cidx  ].p[0]= cr;
00295                     mb->next_cache[next_cidx  ].p[1]= ci;
00296                     mb->next_cache[next_cidx++].val = color[x + y*linesize];
00297                 }
00298                 continue;
00299             }
00300 
00301             use_zyklus= (x==0 || mb->inner!=BLACK ||color[x-1 + y*linesize] == 0xFF000000);
00302             if(use_zyklus)
00303                 epsilon= scale*1*sqrt(SQR(x-mb->w/2) + SQR(y-mb->h/2))/mb->w;
00304 
00305 #define Z_Z2_C(outr,outi,inr,ini)\
00306             outr= inr*inr - ini*ini + cr;\
00307             outi= 2*inr*ini + ci;
00308 
00309 #define Z_Z2_C_ZYKLUS(outr,outi,inr,ini, Z)\
00310             Z_Z2_C(outr,outi,inr,ini)\
00311             if(use_zyklus){\
00312                 if(Z && fabs(mb->zyklus[i>>1][0]-outr)+fabs(mb->zyklus[i>>1][1]-outi) <= epsilon)\
00313                     break;\
00314             }\
00315             mb->zyklus[i][0]= outr;\
00316             mb->zyklus[i][1]= outi;\
00317 
00318 
00319 
00320             for(i=0; i<mb->maxiter-8; i++){
00321                 double t;
00322                 Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
00323                 i++;
00324                 Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
00325                 i++;
00326                 Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
00327                 i++;
00328                 Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
00329                 i++;
00330                 Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
00331                 i++;
00332                 Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
00333                 i++;
00334                 Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
00335                 i++;
00336                 Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
00337                 if(zr*zr + zi*zi > mb->bailout){
00338                     i-= FFMIN(7, i);
00339                     for(; i<mb->maxiter; i++){
00340                         zr= mb->zyklus[i][0];
00341                         zi= mb->zyklus[i][1];
00342                         if(zr*zr + zi*zi > mb->bailout){
00343                             switch(mb->outer){
00344                             case            ITERATION_COUNT: zr = i; break;
00345                             case NORMALIZED_ITERATION_COUNT: zr= i + log2(log(mb->bailout) / log(zr*zr + zi*zi)); break;
00346                             }
00347                             c= lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256;
00348                             break;
00349                         }
00350                     }
00351                     break;
00352                 }
00353             }
00354             if(!c){
00355                 if(mb->inner==PERIOD){
00356                 int j;
00357                 for(j=i-1; j; j--)
00358                     if(SQR(mb->zyklus[j][0]-zr) + SQR(mb->zyklus[j][1]-zi) < epsilon*epsilon*10)
00359                         break;
00360                 if(j){
00361                     c= i-j;
00362                     c= ((c<<5)&0xE0) + ((c<<16)&0xE000) + ((c<<27)&0xE00000);
00363                 }
00364                 }else if(mb->inner==CONVTIME){
00365                     c= floor(i*255.0/mb->maxiter+dv)*0x010101;
00366                 } else if(mb->inner==MINCOL){
00367                     int j;
00368                     double closest=9999;
00369                     int closest_index=0;
00370                     for(j=i-1; j>=0; j--)
00371                         if(SQR(mb->zyklus[j][0]) + SQR(mb->zyklus[j][1]) < closest){
00372                             closest= SQR(mb->zyklus[j][0]) + SQR(mb->zyklus[j][1]);
00373                             closest_index= j;
00374                         }
00375                     closest = sqrt(closest);
00376                     c= lrintf((mb->zyklus[closest_index][0]/closest+1)*127+dv) + lrintf((mb->zyklus[closest_index][1]/closest+1)*127+dv)*256;
00377                 }
00378             }
00379             c |= 0xFF000000;
00380             color[x + y*linesize]= c;
00381             if(next_cidx < mb->cache_allocated){
00382                 mb->next_cache[next_cidx  ].p[0]= cr;
00383                 mb->next_cache[next_cidx  ].p[1]= ci;
00384                 mb->next_cache[next_cidx++].val = c;
00385             }
00386         }
00387         fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci + scale/2, scale);
00388     }
00389     FFSWAP(void*, mb->next_cache, mb->point_cache);
00390     mb->cache_used = next_cidx;
00391     if(mb->cache_used == mb->cache_allocated)
00392         av_log(0, AV_LOG_INFO, "Mandelbrot cache is too small!\n");
00393 }
00394 
00395 static int request_frame(AVFilterLink *link)
00396 {
00397     MBContext *mb = link->src->priv;
00398     AVFilterBufferRef *picref = avfilter_get_video_buffer(link, AV_PERM_WRITE, mb->w, mb->h);
00399     picref->video->sample_aspect_ratio = (AVRational) {1, 1};
00400     picref->pts = mb->pts++;
00401     picref->pos = -1;
00402 
00403     avfilter_start_frame(link, avfilter_ref_buffer(picref, ~0));
00404     draw_mandelbrot(link->src, (uint32_t*)picref->data[0], picref->linesize[0]/4, picref->pts);
00405     avfilter_draw_slice(link, 0, mb->h, 1);
00406     avfilter_end_frame(link);
00407     avfilter_unref_buffer(picref);
00408 
00409     return 0;
00410 }
00411 
00412 AVFilter avfilter_vsrc_mandelbrot = {
00413     .name        = "mandelbrot",
00414     .description = NULL_IF_CONFIG_SMALL("Render a Mandelbrot fractal."),
00415 
00416     .priv_size = sizeof(MBContext),
00417     .init      = init,
00418     .uninit    = uninit,
00419 
00420     .query_formats = query_formats,
00421 
00422     .inputs    = (const AVFilterPad[]) {{ .name = NULL}},
00423 
00424     .outputs   = (const AVFilterPad[]) {{ .name      = "default",
00425                                     .type            = AVMEDIA_TYPE_VIDEO,
00426                                     .request_frame   = request_frame,
00427                                     .config_props    = config_props },
00428                                   { .name = NULL}},
00429 };
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