add visibility table tool

diff --git a/tools/vistab.c b/tools/vistab.c
new file mode 100644 (file)
index 0000000..6341238
--- /dev/null
+++ b/tools/vistab.c
@@ -0,0 +1,117 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+#define NUM_DIRS       8
+#define MAX_DIST       4
+#define FOV                    60
+
+struct cell {
+       int dx, dy;
+};
+
+void calc_vis(int dir);
+int is_visible(float x, float y, float dir);
+
+int main(void)
+{
+       int i;
+
+       printf("struct {int dx, dy;} visoffs[%d][32] = {\n", NUM_DIRS);
+
+       for(i=0; i<NUM_DIRS; i++) {
+
+               printf("\t/* dir %d */\n", i);
+               calc_vis(i);
+       }
+
+       printf("};\n");
+       return 0;
+}
+
+int cellcmp(const void *a, const void *b)
+{
+       const struct cell *ca = a;
+       const struct cell *cb = b;
+       int za = ca->dx * ca->dx + ca->dy * ca->dy;
+       int zb = cb->dx * cb->dx + cb->dy * cb->dy;
+       return zb - za;
+}
+
+void calc_vis(int dir)
+{
+       int i, j, count, col;
+       struct cell vis[512];
+       int x, y;
+       float theta = (float)(dir + 2) / NUM_DIRS * M_PI * 2.0f;
+
+       fprintf(stderr, "DIR: %d (angle: %g)\n", dir, theta * 180.0f / M_PI);
+       count = 0;
+       for(i=0; i<MAX_DIST*2+1; i++) {
+               y = i - MAX_DIST;
+               for(j=0; j<MAX_DIST*2+1; j++) {
+                       x = j - MAX_DIST;
+
+                       if(is_visible(x, y, theta)) {
+                               vis[count].dx = x;
+                               vis[count].dy = y;
+                               count++;
+
+                               fputc('#', stderr);
+                       } else {
+                               fputc('.', stderr);
+                       }
+               }
+               fputc('\n', stderr);
+       }
+       fputc('\n', stderr);
+
+       qsort(vis, count, sizeof *vis, cellcmp);
+
+       printf("\t{");
+       col = 5;
+       for(i=0; i<count; i++) {
+               col += printf("{%d,%d}", vis[i].dx, vis[i].dy);
+               if(i < count - 1) {
+                       if(col > 72) {
+                               fputs(",\n\t ", stdout);
+                               col = 5;
+                       } else {
+                               fputs(", ", stdout);
+                               col += 2;
+                       }
+               }
+       }
+       fputs(dir < NUM_DIRS - 1 ? "},\n" : "}\n", stdout);
+}
+
+#define RAD 1.42
+
+float ptlinedist(float x, float y, float dir)
+{
+       return -y * cos(dir) + sin(dir) * x;
+}
+
+int is_visible(float x, float y, float dir)
+{
+       static const char voffs[][2] = {{-0.5, -0.5}, {0.5, -0.5}, {0.5, 0.5}, {-0.5, 0.5}};
+       float d0, d1;
+       int i;
+       float hfov = 0.5f * FOV * M_PI / 180.0f;
+
+       d0 = ptlinedist(x, y, dir - hfov);
+       d1 = ptlinedist(x, y, dir + hfov);
+       if(d0 >= 0 && d1 <= 0) {
+               return 1;
+       }
+
+       for(i=0; i<4; i++) {
+               d0 = ptlinedist(x + voffs[i][0], y + voffs[i][1], dir - hfov);
+               d1 = ptlinedist(x + voffs[i][0], y + voffs[i][1], dir + hfov);
+
+               if(d0 >= 0 && d1 <= 0) {
+                       return 1;
+               }
+       }
+       return 0;
+}