/*
  * Copyright (c) 2011 Michael Niedermayer
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  *
  * The vsrc_color filter from Stefano Sabatini was used as template to create
  * this
  */
 
 /**
  * @file

  * Mandelbrot fractal renderer

  */
 
 #include "avfilter.h"

 #include "formats.h"
 #include "video.h"

 #include "internal.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/opt.h"

 #include "libavutil/parseutils.h"

 #include <float.h>

 #include <math.h>

 #define SQR(a) ((a)*(a))
 

 enum Outer{
     ITERATION_COUNT,
     NORMALIZED_ITERATION_COUNT,

     WHITE,

     OUTZ,

 };
 

 enum Inner{
     BLACK,

     PERIOD,

     CONVTIME,

     MINCOL,

 };
 

 typedef struct Point {
     double p[2];
     uint32_t val;
 } Point;
 

 typedef struct MBContext {

     const AVClass *class;

     int w, h;

     AVRational frame_rate;

     uint64_t pts;
     int maxiter;
     double start_x;
     double start_y;
     double start_scale;

     double end_scale;
     double end_pts;

     double bailout;

     int outer;
     int inner;

     int cache_allocated;
     int cache_used;
     Point *point_cache;
     Point *next_cache;

     double (*zyklus)[2];

     uint32_t dither;

 
     double morphxf;
     double morphyf;
     double morphamp;

 } MBContext;
 

 #define OFFSET(x) offsetof(MBContext, x)

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

 
 static const AVOption mandelbrot_options[] = {

     {"size",        "set frame size",                OFFSET(w),       AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"},  CHAR_MIN, CHAR_MAX, FLAGS },
     {"s",           "set frame size",                OFFSET(w),       AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"},  CHAR_MIN, CHAR_MAX, FLAGS },

     {"rate",        "set frame rate",                OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"},  CHAR_MIN, CHAR_MAX, FLAGS },
     {"r",           "set frame rate",                OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"},  CHAR_MIN, CHAR_MAX, FLAGS },

     {"maxiter",     "set max iterations number",     OFFSET(maxiter), AV_OPT_TYPE_INT,        {.i64=7189},  1,        INT_MAX, FLAGS },

     {"start_x",     "set the initial x position",    OFFSET(start_x), AV_OPT_TYPE_DOUBLE,     {.dbl=-0.743643887037158704752191506114774}, -100, 100, FLAGS },
     {"start_y",     "set the initial y position",    OFFSET(start_y), AV_OPT_TYPE_DOUBLE,     {.dbl=-0.131825904205311970493132056385139}, -100, 100, FLAGS },
     {"start_scale", "set the initial scale value",   OFFSET(start_scale), AV_OPT_TYPE_DOUBLE, {.dbl=3.0},  0, FLT_MAX, FLAGS },
     {"end_scale",   "set the terminal scale value",  OFFSET(end_scale), AV_OPT_TYPE_DOUBLE,   {.dbl=0.3},  0, FLT_MAX, FLAGS },
     {"end_pts",     "set the terminal pts value",    OFFSET(end_pts), AV_OPT_TYPE_DOUBLE,     {.dbl=400},  0, INT64_MAX, FLAGS },
     {"bailout",     "set the bailout value",         OFFSET(bailout), AV_OPT_TYPE_DOUBLE,     {.dbl=10},   0, FLT_MAX, FLAGS },

     {"morphxf",     "set morph x frequency",         OFFSET(morphxf), AV_OPT_TYPE_DOUBLE,     {.dbl=0.01},   -FLT_MAX, FLT_MAX, FLAGS },
     {"morphyf",     "set morph y frequency",         OFFSET(morphyf), AV_OPT_TYPE_DOUBLE,     {.dbl=0.0123}, -FLT_MAX, FLT_MAX, FLAGS },
     {"morphamp",    "set morph amplitude",           OFFSET(morphamp), AV_OPT_TYPE_DOUBLE,    {.dbl=0},      -FLT_MAX, FLT_MAX, FLAGS },

     {"outer",       "set outer coloring mode",       OFFSET(outer), AV_OPT_TYPE_INT, {.i64=NORMALIZED_ITERATION_COUNT}, 0, INT_MAX, FLAGS, "outer" },

     {"iteration_count", "set iteration count mode",  0, AV_OPT_TYPE_CONST, {.i64=ITERATION_COUNT}, INT_MIN, INT_MAX, FLAGS, "outer" },
     {"normalized_iteration_count", "set normalized iteration count mode",   0, AV_OPT_TYPE_CONST, {.i64=NORMALIZED_ITERATION_COUNT}, INT_MIN, INT_MAX, FLAGS, "outer" },

     {"white", "set white mode",                      0, AV_OPT_TYPE_CONST, {.i64=WHITE}, INT_MIN, INT_MAX, FLAGS, "outer" },

     {"outz",        "set outz mode",                 0, AV_OPT_TYPE_CONST, {.i64=OUTZ}, INT_MIN, INT_MAX, FLAGS, "outer" },

     {"inner",       "set inner coloring mode",       OFFSET(inner), AV_OPT_TYPE_INT, {.i64=MINCOL}, 0, INT_MAX, FLAGS, "inner" },

     {"black",       "set black mode",                0, AV_OPT_TYPE_CONST, {.i64=BLACK}, INT_MIN, INT_MAX, FLAGS, "inner"},
     {"period",      "set period mode",               0, AV_OPT_TYPE_CONST, {.i64=PERIOD}, INT_MIN, INT_MAX, FLAGS, "inner"},
     {"convergence", "show time until convergence",   0, AV_OPT_TYPE_CONST, {.i64=CONVTIME}, INT_MIN, INT_MAX, FLAGS, "inner"},
     {"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"},

 
     {NULL},
 };
 

 AVFILTER_DEFINE_CLASS(mandelbrot);

 static av_cold int init(AVFilterContext *ctx)

 {

     MBContext *s = ctx->priv;

     s->bailout *= s->bailout;

     s->start_scale /=s->h;
     s->end_scale /=s->h;

     s->cache_allocated = s->w * s->h * 3;
     s->cache_used = 0;
     s->point_cache= av_malloc_array(s->cache_allocated, sizeof(*s->point_cache));
     s-> next_cache= av_malloc_array(s->cache_allocated, sizeof(*s-> next_cache));
     s-> zyklus    = av_malloc_array(s->maxiter + 16, sizeof(*s->zyklus));

     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {

     MBContext *s = ctx->priv;

     av_freep(&s->point_cache);
     av_freep(&s-> next_cache);
     av_freep(&s->zyklus);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     static const enum AVPixelFormat pix_fmts[] = {

         AV_PIX_FMT_0BGR32,

         AV_PIX_FMT_NONE

     };
 

     AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
     if (!fmts_list)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, fmts_list);

 }
 
 static int config_props(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->src;

     MBContext *s = ctx->priv;

     if (av_image_check_size(s->w, s->h, 0, ctx) < 0)

         return AVERROR(EINVAL);
 

     inlink->w = s->w;
     inlink->h = s->h;
     inlink->time_base = av_inv_q(s->frame_rate);

 
     return 0;
 }
 

 static void fill_from_cache(AVFilterContext *ctx, uint32_t *color, int *in_cidx, int *out_cidx, double py, double scale){

     MBContext *s = ctx->priv;
     if(s->morphamp)

         return;

     for(; *in_cidx < s->cache_used; (*in_cidx)++){
         Point *p= &s->point_cache[*in_cidx];

         int x;

         if(p->p[1] > py)

             break;

         x= lrint((p->p[0] - s->start_x) / scale + s->w/2);

         if(x<0 || x >= s->w)

             continue;
         if(color) color[x] = p->val;

         if(out_cidx && *out_cidx < s->cache_allocated)
             s->next_cache[(*out_cidx)++]= *p;

     }
 }
 

 static int interpol(MBContext *s, uint32_t *color, int x, int y, int linesize)

 {
     uint32_t a,b,c,d, i;

     uint32_t ipol=0xFF000000;

     int dist;
 

     if(!x || !y || x+1==s->w || y+1==s->h)

         return 0;
 

     dist= FFMAX(FFABS(x-(s->w>>1))*s->h, FFABS(y-(s->h>>1))*s->w);

     if(dist<(s->w*s->h>>3))

         return 0;
 
     a=color[(x+1) + (y+0)*linesize];
     b=color[(x-1) + (y+1)*linesize];
     c=color[(x+0) + (y+1)*linesize];
     d=color[(x+1) + (y+1)*linesize];
 
     if(a&&c){
         b= color[(x-1) + (y+0)*linesize];
         d= color[(x+0) + (y-1)*linesize];
     }else if(b&&d){
         a= color[(x+1) + (y-1)*linesize];
         c= color[(x-1) + (y-1)*linesize];
     }else if(c){
         d= color[(x+0) + (y-1)*linesize];
         a= color[(x-1) + (y+0)*linesize];
         b= color[(x+1) + (y-1)*linesize];
     }else if(d){
         c= color[(x-1) + (y-1)*linesize];
         a= color[(x-1) + (y+0)*linesize];
         b= color[(x+1) + (y-1)*linesize];
     }else
         return 0;
 
     for(i=0; i<3; i++){
         int s= 8*i;
         uint8_t ac= a>>s;
         uint8_t bc= b>>s;
         uint8_t cc= c>>s;
         uint8_t dc= d>>s;
         int ipolab= (ac + bc);
         int ipolcd= (cc + dc);
         if(FFABS(ipolab - ipolcd) > 5)
             return 0;

         if(FFABS(ac-bc)+FFABS(cc-dc) > 20)
             return 0;

         ipol |= ((ipolab + ipolcd + 2)/4)<<s;
     }

     color[x + y*linesize]= ipol;

     return 1;
 }
 

 static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize, int64_t pts)
 {

     MBContext *s = ctx->priv;

     int x,y,i, in_cidx=0, next_cidx=0, tmp_cidx;

     double scale= s->start_scale*pow(s->end_scale/s->start_scale, pts/s->end_pts);

     int use_zyklus=0;

     fill_from_cache(ctx, NULL, &in_cidx, NULL, s->start_y+scale*(-s->h/2-0.5), scale);

     tmp_cidx= in_cidx;

     memset(color, 0, sizeof(*color)*s->w);
     for(y=0; y<s->h; y++){

         int y1= y+1;

         const double ci=s->start_y+scale*(y-s->h/2);

         fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci, scale);

         if(y1<s->h){
             memset(color+linesize*y1, 0, sizeof(*color)*s->w);

             fill_from_cache(ctx, color+linesize*y1, &tmp_cidx, NULL, ci + 3*scale/2, scale);
         }

         for(x=0; x<s->w; x++){

             float av_uninit(epsilon);

             const double cr=s->start_x+scale*(x-s->w/2);

             double zr=cr;
             double zi=ci;

             uint32_t c=0;

             double dv= s->dither / (double)(1LL<<32);
             s->dither= s->dither*1664525+1013904223;

             if(color[x + y*linesize] & 0xFF000000)
                 continue;

             if(!s->morphamp){
                 if(interpol(s, color, x, y, linesize)){
                     if(next_cidx < s->cache_allocated){
                         s->next_cache[next_cidx  ].p[0]= cr;
                         s->next_cache[next_cidx  ].p[1]= ci;
                         s->next_cache[next_cidx++].val = color[x + y*linesize];

                     }
                     continue;

                 }
             }else{

                 zr += cos(pts * s->morphxf) * s->morphamp;
                 zi += sin(pts * s->morphyf) * s->morphamp;

             }

             use_zyklus= (x==0 || s->inner!=BLACK ||color[x-1 + y*linesize] == 0xFF000000);

             if(use_zyklus)

                 epsilon= scale*(abs(x-s->w/2) + abs(y-s->h/2))/s->w;

 #define Z_Z2_C(outr,outi,inr,ini)\
             outr= inr*inr - ini*ini + cr;\
             outi= 2*inr*ini + ci;
 

 #define Z_Z2_C_ZYKLUS(outr,outi,inr,ini, Z)\
             Z_Z2_C(outr,outi,inr,ini)\
             if(use_zyklus){\

                 if(Z && fabs(s->zyklus[i>>1][0]-outr)+fabs(s->zyklus[i>>1][1]-outi) <= epsilon)\

                     break;\

             }\

             s->zyklus[i][0]= outr;\
             s->zyklus[i][1]= outi;\

             for(i=0; i<s->maxiter-8; i++){

                 double t;
                 Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
                 i++;
                 Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
                 i++;
                 Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
                 i++;
                 Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
                 i++;
                 Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
                 i++;
                 Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)
                 i++;
                 Z_Z2_C_ZYKLUS(t, zi, zr, zi, 0)
                 i++;
                 Z_Z2_C_ZYKLUS(zr, zi, t, zi, 1)

                 if(zr*zr + zi*zi > s->bailout){

                     i-= FFMIN(7, i);

                     for(; i<s->maxiter; i++){
                         zr= s->zyklus[i][0];
                         zi= s->zyklus[i][1];
                         if(zr*zr + zi*zi > s->bailout){
                             switch(s->outer){

                             case            ITERATION_COUNT:
                                 zr = i;

                                 c = lrintf((sinf(zr)+1)*127) + lrintf((sinf(zr/1.234)+1)*127)*256*256 + lrintf((sinf(zr/100)+1)*127)*256;

                                 break;
                             case NORMALIZED_ITERATION_COUNT:

                                 zr = i + log2(log(s->bailout) / log(zr*zr + zi*zi));

                                 c = lrintf((sinf(zr)+1)*127) + lrintf((sinf(zr/1.234)+1)*127)*256*256 + lrintf((sinf(zr/100)+1)*127)*256;

                                 break;
                             case                      WHITE:
                                 c = 0xFFFFFF;

                                 break;
                             case                      OUTZ:

                                 zr /= s->bailout;
                                 zi /= s->bailout;

                                 c = (((int)(zr*128+128))&0xFF)*256 + (((int)(zi*128+128))&0xFF);

                             }
                             break;
                         }

                     }

                     break;
                 }
             }

             if(!c){

                 if(s->inner==PERIOD){

                     int j;
                     for(j=i-1; j; j--)

                         if(SQR(s->zyklus[j][0]-zr) + SQR(s->zyklus[j][1]-zi) < epsilon*epsilon*10)

                             break;
                     if(j){
                         c= i-j;
                         c= ((c<<5)&0xE0) + ((c<<10)&0xE000) + ((c<<15)&0xE00000);
                     }

                 }else if(s->inner==CONVTIME){
                     c= floor(i*255.0/s->maxiter+dv)*0x010101;
                 } else if(s->inner==MINCOL){

                     int j;
                     double closest=9999;
                     int closest_index=0;

                     for(j=i-1; j>=0; j--)

                         if(SQR(s->zyklus[j][0]) + SQR(s->zyklus[j][1]) < closest){
                             closest= SQR(s->zyklus[j][0]) + SQR(s->zyklus[j][1]);

                             closest_index= j;
                         }
                     closest = sqrt(closest);

                     c= lrintf((s->zyklus[closest_index][0]/closest+1)*127+dv) + lrintf((s->zyklus[closest_index][1]/closest+1)*127+dv)*256;

                 }

             }

             c |= 0xFF000000;

             color[x + y*linesize]= c;

             if(next_cidx < s->cache_allocated){
                 s->next_cache[next_cidx  ].p[0]= cr;
                 s->next_cache[next_cidx  ].p[1]= ci;
                 s->next_cache[next_cidx++].val = c;

             }

         }

         fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci + scale/2, scale);

     }

     FFSWAP(void*, s->next_cache, s->point_cache);
     s->cache_used = next_cidx;
     if(s->cache_used == s->cache_allocated)

         av_log(ctx, AV_LOG_INFO, "Mandelbrot cache is too small!\n");

 }
 
 static int request_frame(AVFilterLink *link)
 {

     MBContext *s = link->src->priv;
     AVFrame *picref = ff_get_video_buffer(link, s->w, s->h);

     if (!picref)
         return AVERROR(ENOMEM);
 

     picref->sample_aspect_ratio = (AVRational) {1, 1};

     picref->pts = s->pts++;

     draw_mandelbrot(link->src, (uint32_t*)picref->data[0], picref->linesize[0]/4, picref->pts);

     return ff_filter_frame(link, picref);

 }
 

 static const AVFilterPad mandelbrot_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .request_frame = request_frame,
         .config_props  = config_props,
     },

     { NULL }

 };
 

 AVFilter ff_vsrc_mandelbrot = {

     .name          = "mandelbrot",
     .description   = NULL_IF_CONFIG_SMALL("Render a Mandelbrot fractal."),
     .priv_size     = sizeof(MBContext),
     .priv_class    = &mandelbrot_class,
     .init          = init,
     .uninit        = uninit,

     .query_formats = query_formats,

     .inputs        = NULL,
     .outputs       = mandelbrot_outputs,

 };