* rocks.c (hit_rock, pixel_hit_rock): fix more possible bugs.

[vor.git] / rocks.c

diff --git a/rocks.c b/rocks.c
index a594547..114e22f 100644 (file)
--- a/rocks.c
+++ b/rocks.c
@@ -49,15 +49,17 @@ float nrocks_inc_ticks = 2*60*20/(F_ROCKS-I_ROCKS);
 static inline struct rock_struct **
 bucket(int x, int y, int p)
 {
-       int b = (1+x/grid_size) + bw*(1+y/grid_size);
+       int b = (x+grid_size)/grid_size + bw*((y+grid_size)/grid_size);
        return &rock_buckets[p][b];
 }
 
 void
 init_buckets(void)
 {
-       bw = (XSIZE+2*grid_size-1) / grid_size;
-       bh = (YSIZE+2*grid_size-1) / grid_size;
+       int scr_grid_w = (XSIZE+2*grid_size-1) / grid_size;
+       int scr_grid_h = (YSIZE+2*grid_size-1) / grid_size;
+       bw = 1 + scr_grid_w + 1;
+       bh = 1 + scr_grid_h + 1;
        n_buckets = bw * bh;
        
        rock_buckets[0] = malloc(n_buckets * sizeof(struct rock_struct *));
@@ -267,7 +269,7 @@ move_rocks(void)
                        r->x += (r->dx - screendx)*t_frame;
                        r->y += (r->dy - screendy)*t_frame;
 
-                       // clip or resort into other bucket set
+                       // clip it, or sort it into the other bucket set
                        // (either way we move it out of this list).
                        if(r->x + r->image->w < 0 || r->x >= XSIZE
                                        || r->y + r->image->h < 0 || r->y >= YSIZE) {
@@ -304,24 +306,30 @@ hit_in_bucket(struct rock_struct *r, float x, float y, struct shape *shape)
 int
 hit_rocks(float x, float y, struct shape *shape)
 {
-       struct rock_struct **b = bucket(x, y, p);
-       int bdx = ((int)x+shape->w)/grid_size - (int)x/grid_size;
-       int bdy = ((int)y+shape->h)/grid_size - (int)y/grid_size;
-       if(hit_in_bucket(*b, x, y, shape)) return 1;
-       if(hit_in_bucket(*(b-1), x, y, shape)) return 1;
-       if(hit_in_bucket(*(b-bw), x, y, shape)) return 1;
-       if(hit_in_bucket(*(b-bw-1), x, y, shape)) return 1;
-
-       if(bdx) {
-               if(hit_in_bucket(*(b+1), x, y, shape)) return 1;
-               if(hit_in_bucket(*(b+1-bw), x, y, shape)) return 1;
+       int ix, iy;
+       int l, r, t, b;
+       struct rock_struct **bucket;
+
+       ix = x + grid_size; iy = y + grid_size;
+       l = ix / grid_size; r = (ix+shape->w)/grid_size;
+       t = iy / grid_size; b = (iy+shape->h)/grid_size;
+       bucket = &rock_buckets[p][l + t*bw];
+
+       if(hit_in_bucket(*bucket, x, y, shape)) return true;
+       if(l > 0 && hit_in_bucket(*(bucket-1), x, y, shape)) return true;
+       if(t > 0 && hit_in_bucket(*(bucket-bw), x, y, shape)) return true;
+       if(l > 0 && t > 0 && hit_in_bucket(*(bucket-1-bw), x, y, shape)) return true;
+
+       if(r > l) {
+               if(hit_in_bucket(*(bucket+1), x, y, shape)) return true;
+               if(t > 0 && hit_in_bucket(*(bucket+1-bw), x, y, shape)) return true;
        }
-       if(bdy) {
-               if(hit_in_bucket(*(b+bw), x, y, shape)) return 1;
-               if(hit_in_bucket(*(b+bw-1), x, y, shape)) return 1;
+       if(b > t) {
+               if(hit_in_bucket(*(bucket+bw), x, y, shape)) return true;
+               if(l > 0 && hit_in_bucket(*(bucket-1+bw), x, y, shape)) return true;
        }
-       if(bdx && bdy && hit_in_bucket(*(b+bw+1), x, y, shape)) return 1;
-       return 0;
+       if(r > l && b > t && hit_in_bucket(*(bucket+1+bw), x, y, shape)) return true;
+       return false;
 }
 
 int
@@ -337,12 +345,18 @@ pixel_hit_in_bucket(struct rock_struct *r, float x, float y)
 int
 pixel_hit_rocks(float x, float y)
 {
-       struct rock_struct **b = bucket(x, y, p);
-       if(pixel_hit_in_bucket(*b, x, y)) return 1;
-       if(pixel_hit_in_bucket(*(b-1), x, y)) return 1;
-       if(pixel_hit_in_bucket(*(b-bw), x, y)) return 1;
-       if(pixel_hit_in_bucket(*(b-bw-1), x, y)) return 1;
-       return 0;
+       int ix, iy;
+       int l, t;
+       struct rock_struct **bucket;
+
+       ix = x + grid_size; iy = y + grid_size;
+       l = ix / grid_size; t = iy / grid_size;
+       bucket = &rock_buckets[p][l + t*bw];
+       if(pixel_hit_in_bucket(*bucket, x, y)) return true;
+       if(l > 0 && pixel_hit_in_bucket(*(bucket-1), x, y)) return true;
+       if(t > 0 && pixel_hit_in_bucket(*(bucket-bw), x, y)) return true;
+       if(l > 0 && t > 0 && pixel_hit_in_bucket(*(bucket-1-bw), x, y)) return true;
+       return false;
 }
 
 void