megadrive_test2
annotate tools/tunnel.c @ 5:ea70f3da150f
color cycling tunnel
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Tue, 20 Jun 2017 06:08:58 +0300 |
| parents | 72ab63f262bf |
| children |
| rev | line source |
|---|---|
| nuclear@4 | 1 #include <stdio.h> |
| nuclear@4 | 2 #include <stdlib.h> |
| nuclear@4 | 3 #include <math.h> |
| nuclear@4 | 4 |
| nuclear@5 | 5 #define XSZ 320 |
| nuclear@5 | 6 #define YSZ 240 |
| nuclear@4 | 7 |
| nuclear@4 | 8 int main(void) |
| nuclear@4 | 9 { |
| nuclear@4 | 10 int i, j; |
| nuclear@4 | 11 unsigned char *pixels, *pptr; |
| nuclear@5 | 12 float aspect = (float)XSZ / (float)YSZ; |
| nuclear@4 | 13 |
| nuclear@4 | 14 pixels = malloc(XSZ * YSZ); |
| nuclear@4 | 15 pptr = pixels; |
| nuclear@4 | 16 |
| nuclear@4 | 17 for(i=0; i<YSZ; i++) { |
| nuclear@4 | 18 float y = 2.0 * (float)i / (float)YSZ - 1.0; |
| nuclear@4 | 19 for(j=0; j<XSZ; j++) { |
| nuclear@5 | 20 float x = aspect * (2.0 * (float)j / (float)XSZ - 1.0); |
| nuclear@4 | 21 float tu = atan2(y, x) / M_PI * 0.5 + 0.5; |
| nuclear@4 | 22 float d = sqrt(x * x + y * y); |
| nuclear@5 | 23 float tv = d == 0.0 ? 0.0 : 0.5 / d; |
| nuclear@4 | 24 |
| nuclear@5 | 25 int ty = (int)(tv * 64.0) % 14 + 1; |
| nuclear@4 | 26 int tx = (int)(tu * 256.0) & 0xf; |
| nuclear@4 | 27 |
| nuclear@5 | 28 if(d < 0.2) { |
| nuclear@5 | 29 *pptr++ = 0; |
| nuclear@5 | 30 } else { |
| nuclear@5 | 31 *pptr++ = tx ? ty : 0xf; |
| nuclear@5 | 32 } |
| nuclear@4 | 33 } |
| nuclear@4 | 34 } |
| nuclear@4 | 35 |
| nuclear@4 | 36 pptr = pixels; |
| nuclear@4 | 37 printf("P6\n%d %d\n15\n", XSZ, YSZ); |
| nuclear@4 | 38 |
| nuclear@4 | 39 for(i=0; i<YSZ; i++) { |
| nuclear@4 | 40 for(j=0; j<XSZ; j++) { |
| nuclear@4 | 41 unsigned char c = *pptr++; |
| nuclear@4 | 42 putchar(c); |
| nuclear@4 | 43 putchar(c); |
| nuclear@4 | 44 putchar(c); |
| nuclear@4 | 45 } |
| nuclear@4 | 46 } |
| nuclear@4 | 47 fflush(stdout); |
| nuclear@4 | 48 |
| nuclear@4 | 49 return 0; |
| nuclear@4 | 50 } |