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mandelbrot: add dither to convergence & mincol colorings.

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This avoids banding artifacts.
Note, low end TFTs still show some banding.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2011-11-15 21:33:11 +01:00
parent 7575980ba4
commit 04bb26e3ee
1 changed files with 5 additions and 2 deletions
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7
libavfilter/vsrc_mandelbrot.c
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@ -72,6 +72,7 @@ typedef struct {
Point *point_cache; Point *point_cache;
Point *next_cache; Point *next_cache;
double (*zyklus)[2]; double (*zyklus)[2];
uint32_t dither;
} MBContext; } MBContext;
#define OFFSET(x) offsetof(MBContext, x) #define OFFSET(x) offsetof(MBContext, x)
@ -224,6 +225,8 @@ static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize,
double zr=cr; double zr=cr;
double zi=ci; double zi=ci;
uint32_t c=0; uint32_t c=0;
double dv= mb->dither / (double)(1LL<<32);
mb->dither= mb->dither*1664525+1013904223;
if(color[x + y*linesize] & 0xFF000000) if(color[x + y*linesize] & 0xFF000000)
continue; continue;
@ -267,7 +270,7 @@ static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize,
c= ((c<<5)&0xE0) + ((c<<16)&0xE000) + ((c<<27)&0xE00000); c= ((c<<5)&0xE0) + ((c<<16)&0xE000) + ((c<<27)&0xE00000);
} }
}else if(mb->inner==CONVTIME){ }else if(mb->inner==CONVTIME){
c= (i*255/mb->maxiter)*0x010101; c= floor(i*255.0/mb->maxiter+dv)*0x010101;
} else if(mb->inner==MINCOL){ } else if(mb->inner==MINCOL){
int j; int j;
double closest=9999; double closest=9999;
@ -278,7 +281,7 @@ static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize,
closest_index= j; closest_index= j;
} }
closest = sqrt(closest); closest = sqrt(closest);
c= lrintf((mb->zyklus[closest_index][0]/closest+1)*127) + lrintf((mb->zyklus[closest_index][1]/closest+1)*127)*256; c= lrintf((mb->zyklus[closest_index][0]/closest+1)*127+dv) + lrintf((mb->zyklus[closest_index][1]/closest+1)*127+dv)*256;
} }
} }
c |= 0xFF000000; c |= 0xFF000000;