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Author: bigler
Date: Thu Aug 25 14:51:33 2005
New Revision: 500

Modified:
   trunk/Model/Primitives/Parallelogram.cc
Log:

Normalize ray directions to avoid precision problems with the "dt" dot
product.


Modified: trunk/Model/Primitives/Parallelogram.cc
==============================================================================
--- trunk/Model/Primitives/Parallelogram.cc     (original)
+++ trunk/Model/Primitives/Parallelogram.cc     Thu Aug 25 14:51:33 2005
@@ -42,6 +42,11 @@
 
 void Parallelogram::intersect(const RenderContext&, RayPacket& rays) const
 {
+  // You should normalize the directions to make the "dt" dot product
+  // meaningful.  As the ray directions get longer and shorter it can
+  // affect this value.  You should be doing this dot product against
+  // normalized vectors anyway.
+  rays.normalizeDirections();
   if(rays.getFlags() & RayPacket::ConstantOrigin && rays.getSize()>1){
     RayPacket::Element& e0 = rays.get(0);
     double num = d-Dot(normal, e0.ray.origin());

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• [MANTA] r500 - trunk/Model/Primitives, bigler, 08/25/2005

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