now deleting dots which hit rocks.

[vor.git] / shape.c

diff --git a/shape.c b/shape.c
index f457158..5aa7fb7 100644 (file)
--- a/shape.c
+++ b/shape.c
@@ -108,3 +108,14 @@ collide(int xdiff, int ydiff, struct shape *r, struct shape *s)
        if(xov == 0 || yov == 0) return 0;  // bboxes hit?
        else return mask_collide(xov, yov, r, s);
 }
+
+int
+pixel_collide(unsigned int xoff, unsigned int yoff, struct shape *r)
+{
+       uint32_t pmask;
+       
+       if(xoff >= r->w || yoff >= r->h) return 0;
+
+       pmask = 1 << (xoff & 31); xoff >>= 5;
+       return r->mask[yoff*r->mw + xoff] & pmask;
+}