1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
#include <stdio.h>
#include <stdlib.h>
#include <complex.h>
#include <math.h>
#define ite 500
double map(double x, double p1, double p2, double c1, double c2);
double mandel(double y, double x);
int main(){
const int dimx = 800, dimy = 800;
int i, j;
FILE *fp = fopen("out.ppm", "wb");
fprintf(fp, "P6\n%d %d\n255\n", dimx, dimy);
int c;
unsigned char color[3];
unsigned char temp;
for(j=-dimy/2; j<dimy/2; ++j){
for(i=-dimx/2; i<dimx/2; ++i){
temp = (int)mandel(map(j, -dimx/2, dimx/2, -2, 2), map(i, -dimx/2, dimx/2, -2, 2));
color[0] = temp;
color[1] = temp;
color[2] = temp;
fwrite(color, 3, 1, fp);
}
}
fclose(fp);
return 0;
}
double mandel(double y, double x){
int i;
double ca = x,
cb = y;
double zx, zy, tzx, tzy;
zx = x;
zy = y;
for(i=0; i<ite; ++i){
tzx = zx;
tzy = zy;
zx = tzx*tzx - tzy*tzy + ca;
zy = 2*tzx*tzy + cb;
if(zx*zx + zy*zy > 4)
break;
}
return map(i, ite, 0, 0, 255);
}
double map(double x, double p1, double p2, double c1, double c2){
return 1.0*(x-p1)*(c2-c1)/(p2-p1) + c1;
}
|
