X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=fbgfx;a=blobdiff_plain;f=src%2Ftunnel.c;fp=src%2Ftunnel.c;h=a348431ab3c0d6d3e9550257dac91c7ab3f04269;hp=0000000000000000000000000000000000000000;hb=4b522caf5387f8075b7bbb2a2b0475c012157456;hpb=7e9af893a6d14c0136a89648a2fdebab614a662f

diff --git a/src/tunnel.c b/src/tunnel.c
new file mode 100644
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));*/
+		}
+	}
+}