From fa2276f1caf47e932acf99465a4ea8128755c7d6 Mon Sep 17 00:00:00 2001
From: "erwin.coumans" <erwin.coumans@08e121b0-ae19-0410-a57b-3be3395fd4fd>
Date: Thu, 12 Sep 2013 20:25:06 +0000
Subject: [PATCH] add option for slightly more accurate, and slightly slower
 algorithm for ray versus convex, used in btCollisionWorld::rayTest.
 rayResult.m_flags |= btTriangleRaycastCallback::kF_UseGjkConvexRaytest; See
 Demos/RaytestDemo/RaytestDemo.cpp for usage This fixes issue 146, longest
 outstanding from 2008.

---
 Demos/RaytestDemo/RaytestDemo.cpp              |  3 +++
 .../CollisionDispatch/btCollisionWorld.cpp     | 18 ++++++++++++------
 .../NarrowPhaseCollision/btRaycastCallback.h   |  2 +-
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/Demos/RaytestDemo/RaytestDemo.cpp b/Demos/RaytestDemo/RaytestDemo.cpp
index 9fc494f7a..1f5426a2d 100644
--- a/Demos/RaytestDemo/RaytestDemo.cpp
+++ b/Demos/RaytestDemo/RaytestDemo.cpp
@@ -68,6 +68,9 @@ void RaytestDemo::castRays()
 			sDebugDraw.drawLine(from,to,btVector4(0,0,0,1));
 			btCollisionWorld::AllHitsRayResultCallback allResults(from,to);
 			allResults.m_flags |= btTriangleRaycastCallback::kF_KeepUnflippedNormal;
+			//optional kF_UseGjkConvexRaytest flag enabled a slightly more accurate and slightly slower algorithm
+			allResults.m_flags |= btTriangleRaycastCallback::kF_UseGjkConvexRaytest;
+			
 			m_dynamicsWorld->rayTest(from,to,allResults);
 
 			for (int i=0;i<allResults.m_hitFractions.size();i++)
diff --git a/src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp b/src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
index 783aa41c3..60b714976 100644
--- a/src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
+++ b/src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
@@ -287,13 +287,19 @@ void	btCollisionWorld::rayTestSingleInternal(const btTransform& rayFromTrans,con
 
 		btConvexShape* convexShape = (btConvexShape*) collisionShape;
 		btVoronoiSimplexSolver	simplexSolver;
-#define USE_SUBSIMPLEX_CONVEX_CAST 1
-#ifdef USE_SUBSIMPLEX_CONVEX_CAST
-		btSubsimplexConvexCast convexCaster(castShape,convexShape,&simplexSolver);
-#else
-		//btGjkConvexCast	convexCaster(castShape,convexShape,&simplexSolver);
+		btSubsimplexConvexCast subSimplexConvexCaster(castShape,convexShape,&simplexSolver);
+		
+		btGjkConvexCast	gjkConvexCaster(castShape,convexShape,&simplexSolver);
+		
 		//btContinuousConvexCollision convexCaster(castShape,convexShape,&simplexSolver,0);
-#endif //#USE_SUBSIMPLEX_CONVEX_CAST
+		bool condition = true;
+		btConvexCast* convexCasterPtr = 0;
+		if (resultCallback.m_flags & btTriangleRaycastCallback::kF_UseGjkConvexRaytest)
+			convexCasterPtr = &gjkConvexCaster;
+		else
+			convexCasterPtr = &subSimplexConvexCaster;
+		
+		btConvexCast& convexCaster = *convexCasterPtr;
 
 		if (convexCaster.calcTimeOfImpact(rayFromTrans,rayToTrans,colObjWorldTransform,colObjWorldTransform,castResult))
 		{
diff --git a/src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.h b/src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.h
index f012889a7..6df5a4cfe 100644
--- a/src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.h
+++ b/src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.h
@@ -35,7 +35,7 @@ public:
       kF_None                 = 0,
       kF_FilterBackfaces      = 1 << 0,
       kF_KeepUnflippedNormal  = 1 << 1,   // Prevents returned face normal getting flipped when a ray hits a back-facing triangle
-
+	  kF_UseGjkConvexRaytest =  1 << 2,   // Uses a more accurate but slightly slower ray versus convex algorithm
       kF_Terminator        = 0xFFFFFFFF
    };
    unsigned int m_flags;