X-Git-Url: https://git.rohieb.name/MicroTrace.git/blobdiff_plain/7a2c1f3713be127f6e4361fd8f426e78e8965bab..13c3b8d1e2ecf7f1dbd02f9d4bfeb813b36fd40a:/Sphere.cxx

diff --git a/Sphere.cxx b/Sphere.cxx
index 5706cc3..77d4320 100644
--- a/Sphere.cxx
+++ b/Sphere.cxx
@@ -44,11 +44,15 @@ Sphere::GetNormal(Ray& ray)
   Ray tempRay = ray;
 
   // Surface normal is the difference between intersection and center point
-  Intersect(tempRay);
-  // intersection
-  Vec3f i = tempRay.origin() + tempRay.direction() * tempRay.t();
-  // normal
-  Vec3f n = (i - m_center);
-  n.normalize();
-  return n;
+  if(Intersect(tempRay)) {
+    // intersection point
+    Vec3f i = tempRay.origin() + tempRay.direction() * (tempRay.t() - Epsilon);
+    // normal
+    Vec3f n = (i - m_center);
+    n.normalize();
+    return n;
+  } else {
+    // no intersection with ray, so no surface normal
+    return Vec3f(0,0,0);
+  }
 }