star-3d

commit e0a2def7efa54942325497ef71680500c812c3c7
parent a8d1e50b58b70de5b71e3aaefb6288d1b2102d6c
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri,  4 Oct 2019 15:47:52 +0200

Fix an issue in the closest_point_triangle routine

Diffstat:
M
src/s3d_scene_view_point_query.c
 | 
10
++++++----

1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/src/s3d_scene_view_point_query.c b/src/s3d_scene_view_point_query.c
@@ -62,7 +62,7 @@ closest_point_triangle
   float ab[3], ac[3], ap[3], bp[3], cp[3];
   float d1, d2, d3, d4, d5, d6;
   float va, vb, vc;
-  float triangle_area;
+  float rcp_triangle_area;
   float v, w;
   ASSERT(p && a && b && c && closest_pt && uv);
 
@@ -137,14 +137,16 @@ closest_point_triangle
 
   /* The closest point lies in the triangle: compute its barycentric
    * coordinates */
-  triangle_area = va + vb + vc;
-  v = vb * triangle_area;
-  w = vc * triangle_area;
+  rcp_triangle_area = 1.f / (va + vb + vc);
+  v = vb * rcp_triangle_area;
+  w = vc * rcp_triangle_area;
 
   /* Save the uv barycentric coordinates */
   uv[0] = 1.f - v - w;
   uv[1] = v;
 
+  ASSERT(eq_epsf(uv[0] + uv[1] + w, 1.f, 1.e-4f));
+
   /* Use the barycentric coordinates to compute the world space position of the
    * closest point onto the triangle */
   closest_pt[0] = a[0] + v*ab[0] + w*ac[0];