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 struct vec2 {
   7         float x, y;
   8 };
   9
  10 int main(int argc, char **argv)
  11 {
  12         int i, j, frm, imgrad, out_nlines, xsz = 240, ysz = 160, texsz = 128;
  13         int half_y = 0;
  14         int center = 0;
  15         struct vec2 *tunbuf, *tun;
  16         float prev_r;
  17         struct vec2 *buf, *ptr;
  18         char *endp;
  19         int num_frames = 1;
  20
  21         for(i=1; i<argc; i++) {
  22                 if(argv[i][0] == '-') {
  23                         if(argv[i][2] != 0) goto invalopt;
  24                         switch(argv[i][1]) {
  25                         case 's':
  26                                 if(sscanf(argv[++i], "%dx%d", &xsz, &ysz) != 2 || xsz <= 1 || ysz <= 1) {
  27                                         fprintf(stderr, "-s must be followed by WxH\n");
  28                                         return 1;
  29                                 }
  30                                 break;
  31
  32                         case 't':
  33                                 if(!(texsz = atoi(argv[++i])) || texsz > 256) {
  34                                         fprintf(stderr, "-t must be followed by the texture size (1-256)\n");
  35                                         return 1;
  36                                 }
  37                                 break;
  38
  39                         case 'y':
  40                                 half_y = 1;
  41                                 break;
  42
  43                         case 'c':
  44                                 if(!argv[++i]) {
  45                                         fprintf(stderr, "-c must be followed by a center pixel\n");
  46                                         return 1;
  47                                 }
  48                                 center = strtol(argv[i], &endp, 10);
  49                                 if(endp == argv[i]) {
  50                                         fprintf(stderr, "-c invalid center position: %s\n", argv[i]);
  51                                         return 1;
  52                                 }
  53                                 break;
  54
  55                         case 'n':
  56                                 if(!argv[++i]) {
  57                                         fprintf(stderr, "-n must be followed by the number of frames\n");
  58                                         return 1;
  59                                 }
  60                                 if(!(num_frames = atoi(argv[i]))) {
  61                                         fprintf(stderr, "-n invalid number of frames: %s\n", argv[i]);
  62                                         return 1;
  63                                 }
  64                                 break;
  65
  66                         default:
  67                                 goto invalopt;
  68                         }
  69                 } else {
  70 invalopt:       fprintf(stderr, "invalid argument: %s\n", argv[i]);
  71                         return 1;
  72                 }
  73         }
  74
  75         out_nlines = half_y ? ysz / 2 : ysz;
  76
  77         if(!(buf = malloc(xsz * ysz * sizeof *buf))) {
  78                 perror("failed to allocate buffer");
  79                 return 1;
  80         }
  81         imgrad = sqrt(xsz * xsz + ysz * ysz);
  82
  83         FILE *fp = fopen("tun_preview.ppm", "wb");
  84         if(fp) {
  85                 fprintf(fp, "P6\n%d %d\n255\n", xsz, out_nlines * num_frames);
  86         }
  87
  88
  89         for(frm=0; frm<num_frames; frm++) {
  90                 int coffs = num_frames > 1 ? frm * center / (num_frames - 1) : center;
  91
  92 #define UDIV    2048
  93 #define VDIV    32768
  94                 prev_r = 0.0f;
  95 #pragma omp parallel for private(i, j, prev_r, ptr) schedule(dynamic)
  96                 for(i=0; i<VDIV; i++) {
  97                         float v = (float)(VDIV - i) / (float)VDIV;
  98                         float r = 4.0 / v + 16;
  99                         float z = v * coffs;
 100
 101                         /* don't bother drawing rings < 1 pixel apart */
 102                         if(fabs(r - prev_r) < 0.05) continue;
 103
 104                         for(j=0; j<UDIV; j++) {
 105                                 float u = (float)j / (float)(UDIV - 1);
 106                                 float theta = 2.0f * u * M_PI;
 107
 108                                 int x = (int)(cos(theta) * r - z) + xsz / 2;
 109                                 int y = (int)(sin(theta) * r) + ysz / 2;
 110
 111                                 if(x >= 0 && x < xsz && y >= 0 && y < ysz) {
 112                                         ptr = buf + y * xsz + x;
 113                                         ptr->x = u;
 114                                         ptr->y = v * 8;
 115                                 }
 116                         }
 117                         prev_r = r;
 118                 }
 119
 120                 ptr = buf;
 121                 for(i=0; i<out_nlines; i++) {
 122                         for(j=0; j<xsz; j++) {
 123                                 float u = ptr->x;
 124                                 float v = ptr->y;
 125                                 int r = (int)(u * 8.0 * 255.0f) & 0xff;
 126                                 int g = (int)(v * 8.0 * 255.0f) & 0xff;
 127                                 int b = (~(int)(v * 0.5 * 255.0f) & 0xff) + 105;
 128                                 if(b > 255) b = 255;
 129                                 if(b < 0) b = 0;
 130
 131                                 /*if(v > 2.0) r = g = b = 0;*/
 132
 133                                 ptr++;
 134
 135                                 uint16_t out = ((uint16_t)(u * 255.0f) & 0xff) |
 136                                         (((uint16_t)(v * 255.0f) & 0xff) << 8);
 137                                 fwrite(&out, sizeof out, 1, stdout);
 138
 139                                 if(fp) {
 140                                         fputc(r, fp);
 141                                         fputc(g, fp);
 142                                         fputc(b, fp);
 143                                 }
 144                         }
 145                 }
 146
 147         }
 148         fflush(stdout);
 149
 150         if(fp) fclose(fp);
 151         return 0;
 152 }