git.mutantstargoat.com Git - gbajam21/blob - tools/tungen.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <stdint.h>
   4 #include <math.h>
   5
   6 int main(int argc, char **argv)
   7 {
   8         int i, j, xsz = 240, ysz = 160, texsz = 128;
   9         struct vec2 *tunbuf, *tun;
  10         float aspect;
  11
  12         for(i=1; i<argc; i++) {
  13                 if(argv[i][0] == '-') {
  14                         if(argv[i][2] != 0) goto invalopt;
  15                         switch(argv[i][1]) {
  16                         case 's':
  17                                 if(sscanf(argv[++i], "%dx%d", &xsz, &ysz) != 2 || xsz <= 1 || ysz <= 1) {
  18                                         fprintf(stderr, "-s must be followed by WxH\n");
  19                                         return 1;
  20                                 }
  21                                 break;
  22
  23                         case 't':
  24                                 if(!(texsz = atoi(argv[++i])) || texsz > 256) {
  25                                         fprintf(stderr, "-t must be followed by the texture size (1-256)\n");
  26                                         return 1;
  27                                 }
  28                                 break;
  29
  30                         default:
  31                                 goto invalopt;
  32                         }
  33                 } else {
  34 invalopt:       fprintf(stderr, "invalid argument: %s\n", argv[i]);
  35                         return 1;
  36                 }
  37         }
  38
  39         FILE *fp = fopen("tun_preview.ppm", "wb");
  40         if(fp) {
  41                 fprintf(fp, "P6\n%d %d\n255\n", xsz, ysz);
  42         }
  43
  44         aspect = (float)xsz / (float)ysz;
  45
  46         tun = tunbuf;
  47         for(i=0; i<ysz; i++) {
  48                 float y = 2.0f * (float)i / (float)(ysz - 1) - 1.0f;
  49                 for(j=0; j<xsz; j++) {
  50                         float x = (2.0f * (float)j / (float)(xsz - 1) - 1.0f) * aspect;
  51
  52                         float r = sqrt(x * x + y * y);
  53                         float theta = atan2(y, x);
  54
  55                         float u = 0.5f * theta / M_PI + 0.5f;
  56                         float v = 0.8f / r;
  57
  58                         /*
  59                         uint32_t out = ((uint32_t)(u * 65535.0f) & 0xffff) |
  60                                 (((uint32_t)(v * 65535.0f) & 0xffff) << 16);
  61                         */
  62                         uint16_t out = ((uint16_t)(u * 255.0f) & 0xff) |
  63                                 (((uint16_t)(v * 255.0f) & 0xff) << 8);
  64                         fwrite(&out, sizeof out, 1, stdout);
  65
  66                         if(fp) {
  67                                 int cr = (int)(u * 2048.0f) & 0xff;
  68                                 int cb = (int)(r * 2048.0f) & 0xff;
  69                                 fputc(cr, fp);
  70                                 fputc(0, fp);
  71                                 fputc(cb, fp);
  72                         }
  73                 }
  74         }
  75         fflush(stdout);
  76
  77         if(fp) fclose(fp);
  78         return 0;
  79 }