Make empty collision shape for objects without any triangles.

components/resource/bulletshapemanager.cpp

@@ -7,6 +7,7 @@
 #include <osg/Transform>
 #include <osg/TriangleFunctor>
 
+#include <BulletCollision/CollisionShapes/btEmptyShape.h>
 #include <BulletCollision/CollisionShapes/btTriangleMesh.h>
 
 #include <components/misc/osguservalues.hpp>
@@ -77,6 +78,19 @@ namespace Resource
             if (!mTriangleMesh)
                 return osg::ref_ptr<BulletShape>();
 
+            if (mTriangleMesh->getNumTriangles() == 0) 
+            {
+                osg::ref_ptr<BulletShape> shape(new BulletShape);
+                mTriangleMesh.reset(nullptr);
+                auto emptyShape = std::make_unique<btEmptyShape>();
+                shape->mCollisionBox.mExtents[0] = 0.0f;
+                shape->mCollisionBox.mExtents[1] = 0.0f;
+                shape->mCollisionBox.mExtents[2] = 0.0f;
+                shape->mCollisionBox.mCenter = osg::Vec3f(0, 0, 0);
+                shape->mCollisionShape.reset(emptyShape.release());
+                return shape;
+            }
+
             osg::ref_ptr<BulletShape> shape(new BulletShape);
 
             auto triangleMeshShape = std::make_unique<TriangleMeshShape>(mTriangleMesh.release(), true);