nuclear@4: #include <stdio.h>
nuclear@4: #include <stdlib.h>
nuclear@4: #include <math.h>
nuclear@4: 
nuclear@5: #define XSZ		320
nuclear@5: #define YSZ		240
nuclear@4: 
nuclear@4: int main(void)
nuclear@4: {
nuclear@4: 	int i, j;
nuclear@4: 	unsigned char *pixels, *pptr;
nuclear@5: 	float aspect = (float)XSZ / (float)YSZ;
nuclear@4: 
nuclear@4: 	pixels = malloc(XSZ * YSZ);
nuclear@4: 	pptr = pixels;
nuclear@4: 
nuclear@4: 	for(i=0; i<YSZ; i++) {
nuclear@4: 		float y = 2.0 * (float)i / (float)YSZ - 1.0;
nuclear@4: 		for(j=0; j<XSZ; j++) {
nuclear@5: 			float x = aspect * (2.0 * (float)j / (float)XSZ - 1.0);
nuclear@4: 			float tu = atan2(y, x) / M_PI * 0.5 + 0.5;
nuclear@4: 			float d = sqrt(x * x + y * y);
nuclear@5: 			float tv = d == 0.0 ? 0.0 : 0.5 / d;
nuclear@4: 
nuclear@5: 			int ty = (int)(tv * 64.0) % 14 + 1;
nuclear@4: 			int tx = (int)(tu * 256.0) & 0xf;
nuclear@4: 
nuclear@5: 			if(d < 0.2) {
nuclear@5: 				*pptr++ = 0;
nuclear@5: 			} else {
nuclear@5: 				*pptr++ = tx ? ty : 0xf;
nuclear@5: 			}
nuclear@4: 		}
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	pptr = pixels;
nuclear@4: 	printf("P6\n%d %d\n15\n", XSZ, YSZ);
nuclear@4: 
nuclear@4: 	for(i=0; i<YSZ; i++) {
nuclear@4: 		for(j=0; j<XSZ; j++) {
nuclear@4: 			unsigned char c = *pptr++;
nuclear@4: 			putchar(c);
nuclear@4: 			putchar(c);
nuclear@4: 			putchar(c);
nuclear@4: 		}
nuclear@4: 	}
nuclear@4: 	fflush(stdout);
nuclear@4: 
nuclear@4: 	return 0;
nuclear@4: }