Enabled up to three internal substeps for the physics, which means

that we could work with framerates as low as 20 FPS without
getting noticeable changes in the physics.


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/trunk/supertuxkart@1510 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/physics.cpp

@@ -91,7 +91,10 @@ void Physics::update(float dt)
     // are stored in a vector, but only one entry per collision pair
     // of objects.
     m_all_collisions.clear();
-    m_dynamics_world->stepSimulation(dt);
+
+    // Maximum of three substeps. This will work for framerate down to
+    // 20 FPS (bullet default frequency is 60 HZ).
+    m_dynamics_world->stepSimulation(dt, 3);
 
     // Now handle the actual collision. Note: rockets can not be removed
     // inside of this loop, since the same rocket might hit more than one