From cff2ab046a06a3884c3a075925c8a7ae92b5ce3c Mon Sep 17 00:00:00 2001
From: DavidWyand-GG <davew@garagegames.com>
Date: Sun, 9 Feb 2014 18:10:53 -0500
Subject: [PATCH] Bullet physics applyImpulse() fix

Bullet physics requires a local origin be passed into it's
applyImpulse() rather than a world origin.
---
 Engine/source/T3D/physics/bullet/btBody.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/Engine/source/T3D/physics/bullet/btBody.cpp b/Engine/source/T3D/physics/bullet/btBody.cpp
index 0c37de0c5..77c3b8115 100644
--- a/Engine/source/T3D/physics/bullet/btBody.cpp
+++ b/Engine/source/T3D/physics/bullet/btBody.cpp
@@ -335,16 +335,22 @@ void BtBody::applyImpulse( const Point3F &origin, const Point3F &force )
    AssertFatal( mActor, "BtBody::applyImpulse - The actor is null!" );
    AssertFatal( isDynamic(), "BtBody::applyImpulse - This call is only for dynamics!" );
 
+   // Convert the world position to local
+   MatrixF trans = btCast<MatrixF>( mActor->getCenterOfMassTransform() );
+   trans.inverse();
+   Point3F localOrigin( origin );
+   trans.mulP( localOrigin );
+
    if ( mCenterOfMass )
    {
-      Point3F relOrigin( origin );
+      Point3F relOrigin( localOrigin );
       mCenterOfMass->mulP( relOrigin );
       Point3F relForce( force );
       mCenterOfMass->mulV( relForce );
       mActor->applyImpulse( btCast<btVector3>( relForce ), btCast<btVector3>( relOrigin ) );
    }
    else
-      mActor->applyImpulse( btCast<btVector3>( force ), btCast<btVector3>( origin ) );
+      mActor->applyImpulse( btCast<btVector3>( force ), btCast<btVector3>( localOrigin ) );
 
    if ( !mActor->isActive() )
       mActor->activate();