almost

[fbgfx] / src / tunnel.c

diff --git a/src/tunnel.c b/src/tunnel.c
new file mode 100644 (file)
index 0000000..a348431
--- /dev/null
+++ b/src/tunnel.c
@@ -0,0 +1,68 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <imago2.h>
+#include "tunnel.h"
+
+static int xsz, ysz;
+static unsigned int *tunnel_map;
+
+
+int init_tunnel(int x, int y)
+{
+       int i, j;
+       unsigned int *tmap;
+
+       xsz = x;
+       ysz = y;
+
+       printf("precalculating tunnel map...\n");
+
+       if(!(tunnel_map = malloc(xsz * ysz * sizeof *tunnel_map))) {
+               fprintf(stderr, "failed to allocate tunnel map\n");
+               return -1;
+       }
+       tmap = tunnel_map;
+
+       for(i=0; i<ysz; i++) {
+               float y = 2.0 * (float)i / (float)ysz - 0.5;
+               for(j=0; j<xsz; j++) {
+                       float x = 2.0 * (float)j / (float)xsz - 0.5;
+                       float tu = atan2(y, x) / M_PI * 0.5 + 0.5;
+                       float tv = sqrt(x*x + y*y);
+
+                       int tx = (int)(tu * 65535.0) & 0xffff;
+                       int ty = (int)(tv * 65535.0) & 0xffff;
+
+                       *tmap++ = (tx << 16) | ty;
+               }
+       }
+
+       return 0;
+}
+
+void destroy_tunnel(void)
+{
+       free(tunnel_map);
+}
+
+void draw_tunnel(unsigned short *pixels)
+{
+       int i, j, r, g, b;
+       unsigned int *tmap = tunnel_map;
+
+       for(i=0; i<ysz; i++) {
+               for(j=0; j<xsz; j++) {
+                       unsigned int tx = (*tmap >> 16) & 0xffff;
+                       unsigned int ty = *tmap & 0xffff;
+                       ++tmap;
+
+                       r = tx >> 8;
+                       g = ty >> 8;
+
+                       *pixels++ = ((((r >> 3) & 0x1f) << 11) |
+                                       (((g >> 2) & 0x3f) << 5));/* |
+                                       ((b >> 3) & 0x1f));*/
+               }
+       }
+}