From 6c0c28c2eb8d41ee26dd562f332ce72c6a2c76c3 Mon Sep 17 00:00:00 2001
From: Nelsson Huotari <unelsson@gmail.com>
Date: Sat, 30 Jan 2021 16:03:02 +0200
Subject: [PATCH] Get collision box extents and center from
 btBvhTriangleMeshShape

---
 components/resource/bulletshapemanager.cpp | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/components/resource/bulletshapemanager.cpp b/components/resource/bulletshapemanager.cpp
index bcadf51c4..d1da9090d 100644
--- a/components/resource/bulletshapemanager.cpp
+++ b/components/resource/bulletshapemanager.cpp
@@ -86,7 +86,17 @@ public:
             return osg::ref_ptr<BulletShape>();
 
         osg::ref_ptr<BulletShape> shape (new BulletShape);
-        shape->mCollisionShape = new TriangleMeshShape(mTriangleMesh.release(), true);
+        btBvhTriangleMeshShape* triangleMeshShape = new TriangleMeshShape(mTriangleMesh.release(), true);
+        btVector3 aabbMin = triangleMeshShape->getLocalAabbMin();
+        btVector3 aabbMax = triangleMeshShape->getLocalAabbMax();
+        shape->mCollisionBox.extents[0] = (aabbMax[0] - aabbMin[0]) / 2.0f;
+        shape->mCollisionBox.extents[1] = (aabbMax[1] - aabbMin[1]) / 2.0f;
+        shape->mCollisionBox.extents[2] = (aabbMax[2] - aabbMin[2]) / 2.0f;
+        shape->mCollisionBox.center = osg::Vec3f( (aabbMax[0] + aabbMin[0]) / 2.0f,
+                                                  (aabbMax[1] + aabbMin[1]) / 2.0f,
+                                                  (aabbMax[2] + aabbMin[2]) / 2.0f );
+        shape->mCollisionShape = triangleMeshShape;
+
         return shape;
     }