star-3d

commit ea54aeabde131965518bf6355c82ddaa612ac2f4
parent 9a35b047ec21d095f54d05c744ece13105205cb5
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Wed, 16 Oct 2019 12:27:57 +0200

Fix the closes_point routine for a sphere

There was a bug when the query point was the center of the sphere that
defines the closest surface wrt the query position.

Diffstat:
M
src/s3d_scene_view_closest_point.c
 | 
14
++++++++++++--

1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/src/s3d_scene_view_closest_point.c b/src/s3d_scene_view_closest_point.c
@@ -306,7 +306,7 @@ closest_point_sphere
     flip_surface = inst->flip_surface;
   }
 
-  /* Compute the distance from the the query pos to the sphere center */
+  /* Compute the distance from the query pos to the sphere center */
   f3_sub(Ng, query_pos, sphere_pos);
   len = f3_len(Ng);
 
@@ -317,8 +317,18 @@ closest_point_sphere
   if(dst >= args->query->radius)
     return 0;
 
+  /* Normalize the hit normal */
+  if(len > 0) {
+    f3_divf(Ng, Ng, len);
+  } else {
+    /* The query position is equal to the sphere center. Arbitrarily choose the
+     * point along the +X axis as the closest point */
+    Ng[0] = 1.f;
+    Ng[1] = 0.f;
+    Ng[2] = 0.f;
+  }
+
   /* Compute the uv of the found point */
-  f3_divf(Ng, Ng, len); /* Normalize the hit normal */
   sphere_normal_to_uv(Ng, uv);
 
   /* Flip the geometric normal wrt the flip surface flag */