Make sure that no debug drawing happens if debug mode is disabled

(turns out that besides out explicit calls to debug drawing bullet
includes additional calls, and they were still executed even if
debug was disabled).


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@10048 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/physics/irr_debug_drawer.hpp

@@ -41,7 +41,13 @@ class IrrDebugDrawer : public btIDebugDraw
     DebugModeType   m_debug_mode;
 protected:
     virtual void    setDebugMode(int debug_mode) {}
-    virtual int     getDebugMode() const         { return DBG_DrawWireframe;}
+    /** Callback for bullet: if debug drawing should be done or not.
+     *  Note that getDebugMode is even called when debug_drawing is disabled
+     *  (i.e. not via Physics::draw()), but internally from bullet. So 
+     *  we have to make sure to return nodebug if debugging is disabled. */
+    virtual int     getDebugMode() const         
+                    { return m_debug_mode==DM_NONE ? DBG_NoDebug 
+                                                   : DBG_DrawWireframe;}
 public:
                     IrrDebugDrawer();
     void            render(float dt);