[ggt-checkins] SF.net SVN: ggt:[1271] trunk

[<pat...@us...>]

Revision: 1271
          http://ggt.svn.sourceforge.net/ggt/?rev=1271&view=rev
Author:   patrickh
Date:     2011-03-27 17:31:11 +0000 (Sun, 27 Mar 2011)

Log Message:
-----------
Added an overload of gmtl::intersectDoubleSided() for Tri/LineSeg intersection
that ignores the triangle winding.

Submitted by: Sebastian Messerschmidt

Modified Paths:
--------------
    trunk/ChangeLog
    trunk/gmtl/Intersection.h

Modified: trunk/ChangeLog
===================================================================
--- trunk/ChangeLog	2011-03-27 17:26:29 UTC (rev 1270)
+++ trunk/ChangeLog	2011-03-27 17:31:11 UTC (rev 1271)
@@ -1,5 +1,9 @@
 DATE       AUTHOR       CHANGE
 ---------- ------------ -------------------------------------------------------
+2011-03-27 patrickh     Added an overload of gmtl::intersectDoubleSided() for
+                        Tri/LineSeg intersection that ignores the triangle
+                        winding.
+                        Submitted by Sebastian Messerschmidt
 2011-03-27 patrickh     Added a new Sphere/Sphere intersection function.
                         Submitted by Sebastian Messerschmidt
 2010-11-21 patrickh     gmtl.pc is once again generated for pkg-config usage.

Modified: trunk/gmtl/Intersection.h
===================================================================
--- trunk/gmtl/Intersection.h	2011-03-27 17:26:29 UTC (rev 1270)
+++ trunk/gmtl/Intersection.h	2011-03-27 17:31:11 UTC (rev 1271)
@@ -928,6 +928,45 @@
       else
       {  return false; }
    }
+
+   /**
+    * Tests if the given triangle intersects with the given ray, from both
+    * sides.
+    *
+    * @param tri     The triangle (ccw ordering).
+    * @param lineseg The line segment
+    * @param u       Tangent space u-coordinate of the intersection.
+    * @param v       Tangent space v-coordinate of the intersection.
+    * @param t       An indicator of the intersection location.
+    *
+    * @post \p t gives you the intersection point:
+    *       \code sect = lineseg.getDir() * t + lineseg.getOrigin() \endcode
+    *
+    * @return true if the lineseg intersects the triangle.
+    *
+    * @see from http://www.acm.org/jgt/papers/MollerTrumbore97/code.html
+    *
+    * @since 0.7.0
+    */
+   template<class DATA_TYPE>
+   bool intersectDoubleSided(const Tri<DATA_TYPE>& tri,
+                             const LineSeg<DATA_TYPE>& lineseg,
+                             DATA_TYPE& u, DATA_TYPE& v, DATA_TYPE& t)
+   {
+      const DATA_TYPE eps = static_cast<DATA_TYPE>(0.0001010101);
+      const DATA_TYPE l = length(lineseg.getDir());
+
+      if (eps < l)
+      {
+         Ray<DATA_TYPE> temp(lineseg.getOrigin(), lineseg.getDir());
+         const bool result = intersectDoubleSided(tri, temp, u, v, t);
+         return result && t <= static_cast<DATA_TYPE>(1.0);
+      }
+      else
+      {
+         return false;
+      }
+   }
 }
 
 


This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site.