added specular

[csgray] / src / geom.c

diff --git a/src/geom.c b/src/geom.c
index 341e7c3..bd340bf 100644 (file)
--- a/src/geom.c
+++ b/src/geom.c
@@ -300,12 +300,12 @@ static struct hinterv *interval_isect(struct hinterv *a, struct hinterv *b)
        }
 
        /* partial overlap */
-       if(a->end[0].t < b->end[1].t) {
-               res->end[0] = b->end[1];
-               res->end[1] = a->end[0];
+       if(a->end[0].t < b->end[0].t) {
+               res->end[0] = b->end[0];
+               res->end[1] = a->end[1];
        } else {
-               res->end[0] = a->end[1];
-               res->end[1] = a->end[0];
+               res->end[0] = a->end[0];
+               res->end[1] = b->end[1];
        }
        return res;
 }