278 lines
8.8 KiB
C
278 lines
8.8 KiB
C
/*
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* Copyright (c) 2011 Michael Niedermayer
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* The vsrc_color filter from Stefano Sabatini was used as template to create
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* this
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*/
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/**
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* @file
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* Mandelbrot fraktal renderer
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*/
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#include "avfilter.h"
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#include "libavutil/imgutils.h"
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#include "libavutil/parseutils.h"
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#define SQR(a) ((a)*(a))
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enum Outer{
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ITERATION_COUNT,
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NORMALIZED_ITERATION_COUNT,
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};
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enum Inner{
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BLACK,
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PERIOD,
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};
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typedef struct Point {
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double p[2];
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uint32_t val;
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} Point;
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typedef struct {
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int w, h;
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AVRational time_base;
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uint64_t pts;
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int maxiter;
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double start_x;
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double start_y;
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double start_scale;
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double end_scale;
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double end_pts;
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double bailout;
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enum Outer outer;
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enum Inner inner;
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int cache_allocated;
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int cache_used;
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Point *point_cache;
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Point *next_cache;
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double (*zyklus)[2];
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} MBContext;
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static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
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{
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MBContext *mb = ctx->priv;
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char frame_size [128] = "640x480";
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char frame_rate [128] = "25";
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AVRational frame_rate_q;
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mb->maxiter=4096;
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mb->start_x=-0.743643887037158704752191506114774;
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mb->start_y=-0.131825904205311970493132056385139;
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mb->start_scale=3.0;
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mb->end_scale=0.3;
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mb->end_pts=800;
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mb->bailout=10;
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mb->outer= NORMALIZED_ITERATION_COUNT;
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if (args)
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sscanf(args, "%127[^:]:%127[^:]:%d:%lf:%lf:%lf:%lf:%lf:%lf:%d", frame_size, frame_rate,
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&mb->maxiter, &mb->start_x, &mb->start_y, &mb->start_scale, &mb->end_scale,
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&mb->end_pts, &mb->bailout, &mb->outer);
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mb->bailout *= mb->bailout;
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if (av_parse_video_size(&mb->w, &mb->h, frame_size) < 0) {
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av_log(ctx, AV_LOG_ERROR, "Invalid frame size: %s\n", frame_size);
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return AVERROR(EINVAL);
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}
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mb->start_scale /=mb->h;
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mb->end_scale /=mb->h;
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if (av_parse_video_rate(&frame_rate_q, frame_rate) < 0 ||
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frame_rate_q.den <= 0 || frame_rate_q.num <= 0) {
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av_log(ctx, AV_LOG_ERROR, "Invalid frame rate: %s\n", frame_rate);
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return AVERROR(EINVAL);
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}
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mb->time_base.num = frame_rate_q.den;
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mb->time_base.den = frame_rate_q.num;
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mb->cache_allocated = mb->w * mb->h * 3;
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mb->cache_used = 0;
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mb->point_cache= av_malloc(sizeof(*mb->point_cache)*mb->cache_allocated);
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mb-> next_cache= av_malloc(sizeof(*mb-> next_cache)*mb->cache_allocated);
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mb-> zyklus = av_malloc(sizeof(*mb->zyklus) * mb->maxiter);
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return 0;
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}
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static av_cold void uninit(AVFilterContext *ctx)
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{
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MBContext *mb = ctx->priv;
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av_freep(&mb->point_cache);
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av_freep(&mb-> next_cache);
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av_freep(&mb->zyklus);
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}
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static int query_formats(AVFilterContext *ctx)
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{
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static const enum PixelFormat pix_fmts[] = {
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PIX_FMT_BGR32,
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PIX_FMT_NONE
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};
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avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
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return 0;
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}
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static int config_props(AVFilterLink *inlink)
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{
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AVFilterContext *ctx = inlink->src;
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MBContext *mb = ctx->priv;
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if (av_image_check_size(mb->w, mb->h, 0, ctx) < 0)
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return AVERROR(EINVAL);
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inlink->w = mb->w;
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inlink->h = mb->h;
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inlink->time_base = mb->time_base;
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return 0;
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}
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static void fill_from_cache(AVFilterContext *ctx, uint32_t *color, int *in_cidx, int *out_cidx, double py, double scale){
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MBContext *mb = ctx->priv;
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for(; *in_cidx < mb->cache_used; (*in_cidx)++){
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Point *p= &mb->point_cache[*in_cidx];
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int x;
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if(*in_cidx >= mb->cache_used || p->p[1] > py)
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break;
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x= round((p->p[0] - mb->start_x) / scale + mb->w/2);
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if(x<0 || x >= mb->w)
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continue;
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if(color) color[x] = p->val;
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if(out_cidx && *out_cidx < mb->cache_allocated)
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mb->next_cache[(*out_cidx)++]= *p;
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}
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}
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static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize, int64_t pts)
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{
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MBContext *mb = ctx->priv;
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int x,y,i, in_cidx=0, next_cidx=0, tmp_cidx;
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double scale= mb->start_scale*pow(mb->end_scale/mb->start_scale, pts/mb->end_pts);
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int use_zyklus=0;
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fill_from_cache(ctx, NULL, &in_cidx, NULL, mb->start_y+scale*(-mb->h/2-0.5), scale);
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for(y=0; y<mb->h; y++){
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const double ci=mb->start_y+scale*(y-mb->h/2);
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memset(color+linesize*y, 0, sizeof(*color)*mb->w);
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fill_from_cache(ctx, color+linesize*y, &in_cidx, &next_cidx, ci, scale);
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tmp_cidx= in_cidx;
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fill_from_cache(ctx, color+linesize*y, &tmp_cidx, NULL, ci + scale/2, scale);
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for(x=0; x<mb->w; x++){
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const double cr=mb->start_x+scale*(x-mb->w/2);
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double zr=cr;
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double zi=ci;
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uint32_t c=0;
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if(color[x + y*linesize] & 0xFF000000)
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continue;
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use_zyklus= (x==0 || mb->inner!=BLACK ||color[x-1 + y*linesize] == 0xFF000000);
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for(i=0; i<mb->maxiter; i++){
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double t;
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if(zr*zr + zi*zi > mb->bailout){
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switch(mb->outer){
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case ITERATION_COUNT: zr = i - (SQR(zr-cr)+SQR(zi-ci) > SQR(mb->bailout)); break;
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case NORMALIZED_ITERATION_COUNT: zr= i + log2(log(mb->bailout) / log(zr*zr + zi*zi)); break;
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}
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c= lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256;
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break;
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}
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t= zr*zr - zi*zi + cr;
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zi= 2*zr*zi + ci;
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if(use_zyklus){
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mb->zyklus[i][0]= t;
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mb->zyklus[i][1]= zi;
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}
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i++;
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zr= t*t - zi*zi+cr;
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zi= 2*t*zi + ci;
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if(use_zyklus){
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if(mb->zyklus[i>>1][0]==zr && mb->zyklus[i>>1][1]==zi)
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break;
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mb->zyklus[i][0]= zr;
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mb->zyklus[i][1]= zi;
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}
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}
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if(!c && mb->inner==PERIOD){
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int j;
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for(j=i-1; j; j--)
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if(SQR(mb->zyklus[j][0]-zr) + SQR(mb->zyklus[j][1]-zi) < 0.0000000000000001)
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break;
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if(j){
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c= i-j;
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c= ((c<<5)&0xE0) + ((c<<16)&0xE000) + ((c<<27)&0xE00000);
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}
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}
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c |= 0xFF000000;
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color[x + y*linesize]= c;
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if(next_cidx < mb->cache_allocated){
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mb->next_cache[next_cidx ].p[0]= cr;
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mb->next_cache[next_cidx ].p[1]= ci;
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mb->next_cache[next_cidx++].val = c;
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}
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}
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fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci + scale/2, scale);
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}
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FFSWAP(void*, mb->next_cache, mb->point_cache);
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mb->cache_used = next_cidx;
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if(mb->cache_used == mb->cache_allocated)
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av_log(0, AV_LOG_INFO, "Mandelbrot cache is too small!\n");
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}
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static int request_frame(AVFilterLink *link)
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{
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MBContext *mb = link->src->priv;
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AVFilterBufferRef *picref = avfilter_get_video_buffer(link, AV_PERM_WRITE, mb->w, mb->h);
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picref->video->sample_aspect_ratio = (AVRational) {1, 1};
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picref->pts = mb->pts++;
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picref->pos = -1;
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avfilter_start_frame(link, avfilter_ref_buffer(picref, ~0));
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draw_mandelbrot(link->src, picref->data[0], picref->linesize[0]/4, picref->pts);
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avfilter_draw_slice(link, 0, mb->h, 1);
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avfilter_end_frame(link);
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avfilter_unref_buffer(picref);
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return 0;
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}
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AVFilter avfilter_vsrc_mandelbrot = {
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.name = "mandelbrot",
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.description = NULL_IF_CONFIG_SMALL("Mandelbrot renderer"),
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.priv_size = sizeof(MBContext),
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.init = init,
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.uninit = uninit,
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.query_formats = query_formats,
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.inputs = (const AVFilterPad[]) {{ .name = NULL}},
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.outputs = (const AVFilterPad[]) {{ .name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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.request_frame = request_frame,
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.config_props = config_props },
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{ .name = NULL}},
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};
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