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mandelbrot: unroll the innermost loop once.

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This allows us to remove a if() and a variable assignment.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2011-11-13 16:55:28 +01:00
parent 1d06608732
commit 88166fc579
1 changed files with 17 additions and 3 deletions
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20
libavfilter/vsrc_mandelbrot.c
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@ -190,11 +190,25 @@ static void draw_mandelbrot(AVFilterContext *ctx, uint32_t *color, int linesize,
c= lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256; c= lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256;
break; break;
} }
t= zr*zr - zi*zi; t= zr*zr - zi*zi + cr;
zi= 2*zr*zi + ci; zi= 2*zr*zi + ci;
zr= t + cr;
if(use_zyklus){ if(use_zyklus){
if((i&1) && mb->zyklus[i>>1][0]==zr && mb->zyklus[i>>1][1]==zi) mb->zyklus[i][0]= t;
mb->zyklus[i][1]= zi;
}
i++;
if(t*t + zi*zi > mb->bailout){
switch(mb->outer){
case ITERATION_COUNT: zr= i; break;
case NORMALIZED_ITERATION_COUNT: zr= i + (log(log(mb->bailout)) - log(log(sqrt(t*t + zi*zi))))/log(2); break;
}
c= lrintf((sin(zr)+1)*127) + lrintf((sin(zr/1.234)+1)*127)*256*256 + lrintf((sin(zr/100)+1)*127)*256;
break;
}
zr= t*t - zi*zi+cr;
zi= 2*t*zi + ci;
if(use_zyklus){
if(mb->zyklus[i>>1][0]==zr && mb->zyklus[i>>1][1]==zi)
break; break;
mb->zyklus[i][0]= zr; mb->zyklus[i][0]= zr;
mb->zyklus[i][1]= zi; mb->zyklus[i][1]= zi;