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

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <stdint.h>
   5 #include <math.h>
   6
   7 struct vec2 {
   8         int x, y;
   9 };
  10
  11 int main(int argc, char **argv)
  12 {
  13         int i, j, frm, imgrad, out_nlines, xsz = 240, ysz = 160, texsz = 128;
  14         int half_y = 0;
  15         int center = 0;
  16         struct vec2 *tunbuf, *tun;
  17         float prev_r;
  18         struct vec2 *buf, *ptr;
  19         char *endp;
  20         int num_frames = 1;
  21
  22         for(i=1; i<argc; i++) {
  23                 if(argv[i][0] == '-') {
  24                         if(argv[i][2] != 0) goto invalopt;
  25                         switch(argv[i][1]) {
  26                         case 's':
  27                                 if(sscanf(argv[++i], "%dx%d", &xsz, &ysz) != 2 || xsz <= 1 || ysz <= 1) {
  28                                         fprintf(stderr, "-s must be followed by WxH\n");
  29                                         return 1;
  30                                 }
  31                                 break;
  32
  33                         case 't':
  34                                 if(!(texsz = atoi(argv[++i])) || texsz > 256) {
  35                                         fprintf(stderr, "-t must be followed by the texture size (1-256)\n");
  36                                         return 1;
  37                                 }
  38                                 break;
  39
  40                         case 'y':
  41                                 half_y = 1;
  42                                 break;
  43
  44                         case 'c':
  45                                 if(!argv[++i]) {
  46                                         fprintf(stderr, "-c must be followed by a center pixel\n");
  47                                         return 1;
  48                                 }
  49                                 center = strtol(argv[i], &endp, 10);
  50                                 if(endp == argv[i]) {
  51                                         fprintf(stderr, "-c invalid center position: %s\n", argv[i]);
  52                                         return 1;
  53                                 }
  54                                 break;
  55
  56                         case 'n':
  57                                 if(!argv[++i]) {
  58                                         fprintf(stderr, "-n must be followed by the number of frames\n");
  59                                         return 1;
  60                                 }
  61                                 if(!(num_frames = atoi(argv[i]))) {
  62                                         fprintf(stderr, "-n invalid number of frames: %s\n", argv[i]);
  63                                         return 1;
  64                                 }
  65                                 break;
  66
  67                         default:
  68                                 goto invalopt;
  69                         }
  70                 } else {
  71 invalopt:       fprintf(stderr, "invalid argument: %s\n", argv[i]);
  72                         return 1;
  73                 }
  74         }
  75
  76         out_nlines = half_y ? ysz / 2 : ysz;
  77
  78         if(!(buf = malloc(xsz * ysz * sizeof *buf))) {
  79                 perror("failed to allocate buffer");
  80                 return 1;
  81         }
  82         imgrad = sqrt(xsz * xsz + ysz * ysz);
  83
  84         FILE *fp = fopen("tun_preview.ppm", "wb");
  85         if(fp) {
  86                 fprintf(fp, "P6\n%d %d\n255\n", xsz, out_nlines * num_frames);
  87         }
  88
  89
  90         for(frm=0; frm<num_frames; frm++) {
  91                 int coffs = num_frames > 1 ? frm * center / (num_frames - 1) : center;
  92
  93                 memset(buf, 0xff, xsz * ysz * sizeof *buf);
  94
  95 #define UDIV    2048
  96 #define VDIV    32768
  97                 prev_r = 0.0f;
  98 #pragma omp parallel for private(i, j, prev_r, ptr) schedule(dynamic)
  99                 for(i=0; i<VDIV; i++) {
 100                         float v = (float)(VDIV - i) / (float)VDIV;
 101                         float r = 4.0 / v + 16;
 102                         float z = v * coffs;
 103
 104                         /* don't bother drawing rings < 1 pixel apart */
 105                         if(r < 0 || fabs(r - prev_r) < 0.05) continue;
 106
 107                         for(j=0; j<UDIV; j++) {
 108                                 float u = (float)j / (float)(UDIV - 1);
 109                                 float theta = 2.0f * u * M_PI;
 110
 111                                 int x = (int)(cos(theta) * r - z) + xsz / 2;
 112                                 int y = (int)(sin(theta) * r) + ysz / 2;
 113
 114                                 if(x >= 0 && x < xsz && y >= 0 && y < ysz) {
 115                                         ptr = buf + y * xsz + x;
 116                                         ptr->x = (j << 8) / UDIV;
 117                                         ptr->y = ((VDIV - i) << 11) / VDIV;
 118                                 }
 119                         }
 120                         prev_r = r;
 121                 }
 122
 123                 ptr = buf;
 124                 for(i=0; i<out_nlines; i++) {
 125                         for(j=0; j<xsz; j++) {
 126                                 int u = ptr->x;
 127                                 int v = ptr->y;
 128                                 int r = (u << 3) & 0xff;
 129                                 int g = (v >> 3) & 0xff;
 130
 131                                 /*if(v > 2.0) r = g = b = 0;*/
 132
 133                                 ptr++;
 134
 135                                 uint16_t out = ((uint16_t)u & 0x3f) | (((uint16_t)v & 0x3ff) << 6);
 136                                 fwrite(&out, sizeof out, 1, stdout);
 137
 138                                 if(fp) {
 139                                         fputc(r, fp);
 140                                         fputc(g, fp);
 141                                         fputc(0, fp);
 142                                 }
 143                         }
 144                 }
 145
 146         }
 147         fflush(stdout);
 148
 149         if(fp) fclose(fp);
 150         return 0;
 151 }