fix GPU code

fresnel/gpu/GeometryConvexPolyhedron.cu

@@ -132,7 +132,7 @@ RT_PROGRAM void intersect(int item)
     vec3<float> t0_n_local(0, 0, 0), t0_p_local(0, 0, 0);
     vec3<float> t1_n_local(0, 0, 0), t1_p_local(0, 0, 0);
     int t0_plane_hit = 0, t1_plane_hit = 0;
-    for (int i = 0; i < n_planes && t0 < t1; ++i)
+    for (int i = 0; i < n_planes && t0 <= t1; ++i)
         {
         vec3<float> n = vec3<float>(convex_polyhedron_plane_normal[i]);
         vec3<float> p = vec3<float>(convex_polyhedron_plane_origin[i]);