1 files changed, 16 insertions, 4 deletions

diff --git a/extern/bullet2/src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.cpp b/extern/bullet2/src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.cpp
index a70a3ae56c4..cdb1d22444d 100644
--- a/extern/bullet2/src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.cpp
+++ b/extern/bullet2/src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.cpp
@@ -23,10 +23,12 @@ subject to the following restrictions:
 #include "BulletCollision/NarrowPhaseCollision/btGjkEpaPenetrationDepthSolver.h"
 #include "btRaycastCallback.h"
 
-btTriangleRaycastCallback::btTriangleRaycastCallback(const btVector3& from,const btVector3& to)
+btTriangleRaycastCallback::btTriangleRaycastCallback(const btVector3& from,const btVector3& to, unsigned int flags)
 	:
 	m_from(from),
 	m_to(to),
+   //@BP Mod
+   m_flags(flags),
 	m_hitFraction(btScalar(1.))
 {
 
@@ -55,6 +57,12 @@ void btTriangleRaycastCallback::processTriangle(btVector3* triangle,int partId,
 	{
 		return ; // same sign
 	}
+   //@BP Mod - Backface filtering
+   if (((m_flags & kF_FilterBackfaces) != 0) && (dist_a > btScalar(0.0)))
+   {
+      // Backface, skip check
+      return;
+   }
 	
 	const btScalar proj_length=dist_a-dist_b;
 	const btScalar distance = (dist_a)/(proj_length);
@@ -89,14 +97,18 @@ void btTriangleRaycastCallback::processTriangle(btVector3* triangle,int partId,
 					
 					if ( (btScalar)(cp2.dot(triangleNormal)) >=edge_tolerance) 
 					{
+                  //@BP Mod
+                  // Triangle normal isn't normalized
+				      triangleNormal.normalize();
 
-						if ( dist_a > 0 )
+                  //@BP Mod - Allow for unflipped normal when raycasting against backfaces
+                  if (((m_flags & kF_KeepUnflippedNormal) != 0) || (dist_a <= btScalar(0.0)))
 						{
-							m_hitFraction = reportHit(triangleNormal,distance,partId,triangleIndex);
+							m_hitFraction = reportHit(-triangleNormal,distance,partId,triangleIndex);
 						}
 						else
 						{
-							m_hitFraction = reportHit(-triangleNormal,distance,partId,triangleIndex);
+                     m_hitFraction = reportHit(triangleNormal,distance,partId,triangleIndex);
 						}
 					}
 				}