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mandelbrot: use cache to avoid recalculating points.

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Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2011-11-12 15:44:13 +01:00
parent 8ca891fc1a
commit 07f272bdbb
1 changed files with 52 additions and 3 deletions
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55
libavfilter/vsrc_mandelbrot.c
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@ -35,6 +35,11 @@ enum Outer{
NORMALIZED_ITERATION_COUNT,
};
typedef struct Point {
double p[2];
uint32_t val;
} Point;
typedef struct {
int w, h;
AVRational time_base;
@ -47,6 +52,10 @@ typedef struct {
double end_pts;
double bailout;
enum Outer outer;
int cache_allocated;
int cache_used;
Point *point_cache;
Point *next_cache;
} MBContext;
static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
@ -83,6 +92,11 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
mb->time_base.num = frame_rate_q.den;
mb->time_base.den = frame_rate_q.num;
mb->cache_allocated = mb->w * mb->h*2;
mb->cache_used = 0;
mb->point_cache= av_malloc(sizeof(*mb->point_cache)*mb->cache_allocated);
mb-> next_cache= av_malloc(sizeof(*mb-> next_cache)*mb->cache_allocated);
return 0;
}
@ -91,6 +105,8 @@ static av_cold void uninit(AVFilterContext *ctx)
MBContext *mb = ctx->priv;
int i;
av_freep(&mb->point_cache);
av_freep(&mb-> next_cache);
}
static int query_formats(AVFilterContext *ctx)
@ -119,21 +135,45 @@ static int config_props(AVFilterLink *inlink)
return 0;
}
static void fill_from_cache(AVFilterContext *ctx, uint32_t *color, int *in_cidx, int *out_cidx, double py, double scale){
MBContext *mb = ctx->priv;
for(; *in_cidx < mb->cache_used; (*in_cidx)++){
Point *p= &mb->point_cache[*in_cidx];
int x;
if(*in_cidx >= mb->cache_used || p->p[1] > py)
break;
x= round((p->p[0] - mb->start_x) / scale + mb->w/2);
if(x<0 || x >= mb->w)
continue;
if(color) color[x] = p->val;
if(out_cidx && *out_cidx < mb->cache_allocated)
mb->next_cache[(*out_cidx)++]= *p;
}
}
static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize, int64_t pts)
{
MBContext *mb = ctx->priv;
int x,y,i;
int x,y,i, in_cidx=0, next_cidx=0, tmp_cidx;
double scale= mb->start_scale*pow(mb->end_scale/mb->start_scale, pts/mb->end_pts);
fill_from_cache(ctx, NULL, &in_cidx, NULL, mb->start_y+scale*(-mb->h/2-0.5), scale);
for(y=0; y<mb->h; y++){
const double ci=mb->start_y+scale*(y-mb->h/2);
memset(color+linesize*y, 0, sizeof(*color)*mb->w);
fill_from_cache(ctx, color+linesize*y, &in_cidx, &next_cidx, ci, scale);
tmp_cidx= in_cidx;
fill_from_cache(ctx, color+linesize*y, &tmp_cidx, NULL, ci + scale/2, scale);
for(x=0; x<mb->w; x++){
const double cr=mb->start_x+scale*(x-mb->w/2);
const double ci=mb->start_y+scale*(y-mb->h/2);
double zr=cr;
double zi=ci;
uint32_t c=0;
if(color[x + y*linesize] & 0xFF000000)
continue;
for(i=0; i<mb->maxiter; i++){
double t;
if(zr*zr + zi*zi > mb->bailout){
@ -148,9 +188,18 @@ static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize,
zi= 2*zr*zi + ci;
zr= t + cr;
}
c |= 0xFF000000;
color[x + y*linesize]= c;
if(next_cidx < mb->cache_allocated){
mb->next_cache[next_cidx ].p[0]= cr;
mb->next_cache[next_cidx ].p[1]= ci;
mb->next_cache[next_cidx++].val = c;
}
}
fill_from_cache(ctx, NULL, &in_cidx, &next_cidx, ci + scale/2, scale);
}
FFSWAP(void*, mb->next_cache, mb->point_cache);
mb->cache_used = next_cidx;
}
static int request_frame(AVFilterLink *link)