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/*
!!DESCRIPTION!! mandelbrot test program
!!ORIGIN!! testsuite
!!LICENCE!! Public Domain
!!AUTHOR!! Groepaz/Hitmen
*/
#include <stdio.h>
#include <stdlib.h>
static unsigned short SCREEN_X;
static unsigned char SCREEN_Y;
#define MAXCOL 8
#define maxiterations 16
#define fpshift (12)
#define tofp(_x) ((_x)<<fpshift)
#define fromfp(_x) ((_x)>>fpshift)
#define fpabs(_x) (abs(_x))
#define mulfp(_a,_b) ((((signed long)_a)*(_b))>>fpshift)
#define divfp(_a,_b) ((((signed long)_a)<<fpshift)/(_b))
unsigned char dither[MAXCOL]={" .*o+0%#"};
void mandelbrot(signed short x1,signed short y1,signed short x2,signed short y2)
{
register signed short r,r1,i;
register unsigned char count;
register signed short xs,ys,xx,yy;
register signed short x;
register unsigned char y;
/* calc stepwidth */
xs=((x2-x1)/(SCREEN_X));
ys=((y2-y1)/(SCREEN_Y));
yy=y1;
for(y = 0; y < (SCREEN_Y); ++y)
{
yy+=ys; xx=x1;
for(x = 0; x < (SCREEN_X); ++x)
{
xx+=xs;
/* do iterations */
r=0;i=0;
for(count=0;(count<maxiterations)&&
(fpabs(r)<tofp(2))&&
(fpabs(i)<tofp(2))
;++count)
{
r1 = (mulfp(r,r)-mulfp(i,i))+xx;
/* i = (mulfp(mulfp(r,i),tofp(2)))+yy; */
i = (((signed long)r*i)>>(fpshift-1))+yy;
r=r1;
}
if(count==maxiterations)
{
printf(" ");
}
else
{
printf("%c",dither[(count%MAXCOL)]);
}
}
printf("\n");
}
}
int main (void)
{
SCREEN_X = 80;
SCREEN_Y = 40;
/* calc mandelbrot set */
mandelbrot(tofp(-2),tofp(-2),tofp(2),tofp(2));
/* Done */
return 0;
}
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