Made z-velocity adjustment for flyables optional. Disabling this

fixed the gravity handling for the bowling ball.


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/trunk/supertuxkart@2280 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/bowling.cpp

@@ -47,7 +47,13 @@ Bowling::Bowling(Kart *kart) : Flyable(kart, COLLECT_BOWLING)
     }
 
     createPhysics(y_offset, btVector3(0.0f, m_speed*2, 0.0f),
-                  new btSphereShape(0.5f*m_extend.getY()), true /*gravity*/, true /*rotates*/);
+                  new btSphereShape(0.5f*m_extend.getY()), 
+                  true /*gravity*/, 
+                  true /*rotates*/);
+
+    // Do not adjust the z velociy depending on height above terrain, since
+    // this would disable gravity.
+    setAdjustZVelocity(false);
 
     // unset no_contact_response flags, so that the ball 
     // will bounce off the track
@@ -73,10 +79,10 @@ void Bowling::init(const lisp::Lisp* lisp, ssgEntity *bowling)
 // -----------------------------------------------------------------------------
 void Bowling::update(float dt)
 {
-    Flyable::update(dt);
+    Flyable::update(dt);    
     const Kart *kart=0;
-    btVector3 direction;
-    float minDistance;
+    btVector3   direction;
+    float       minDistance;
     getClosestKart(&kart, &minDistance, &direction);
     if(minDistance<m_st_max_distance_squared)   // move bowling towards kart
     {

src/flyable.cpp

@@ -52,6 +52,7 @@ Flyable::Flyable(Kart *kart, CollectableType type, float mass) : Moveable(false)
     m_exploded          = false;
     m_shape             = NULL;
     m_mass              = mass;
+    m_adjust_z_velocity = true;
 
     // Add the graphical model
     ssgTransform *m     = getModelTransform();
@@ -170,17 +171,19 @@ void Flyable::update (float dt)
         explode(NULL);    // flyable out of track boundary
         return;
     }
+    if(m_adjust_z_velocity)
+    {
+        float hat = pos.getZ()-getHoT();
 
-    float hat = pos.getZ()-getHoT();
-
-    // Use the Height Above Terrain to set the Z velocity.
-    // HAT is clamped by min/max height. This might be somewhat
-    // unphysical, but feels right in the game.
-    hat = std::max(std::min(hat, m_max_height) , m_min_height);
-    float delta = m_average_height - hat;
-    btVector3 v=getVelocity();
-    v.setZ(m_force_updown*delta);
-    setVelocity(v);
+        // Use the Height Above Terrain to set the Z velocity.
+        // HAT is clamped by min/max height. This might be somewhat
+        // unphysical, but feels right in the game.
+        hat = std::max(std::min(hat, m_max_height) , m_min_height);
+        float delta = m_average_height - hat;
+        btVector3 v=getVelocity();
+        v.setZ(m_force_updown*delta);
+        setVelocity(v);
+    }   // if m_adjust_z_velocity
 
     Moveable::update(dt);
 }   // update

src/flyable.hpp

@@ -34,8 +34,12 @@ private:
     bool              m_has_hit_something;
     /** This flag is used to avoid that a rocket explodes mode than once.
      *  It can happen that more than one collision between a rocket and
-     *  a track or kart is reported by the physics.                       */   
+     *  a track or kart is reported by the physics.                        */   
     bool              m_exploded;
+    /** If this flag is set, the Z velocity of the kart will not be
+     *  adjusted in case that the objects is too high or too low above the 
+     *  terrain. Otherwise gravity will not work correctly on this object. */
+    bool              m_adjust_z_velocity;
 
 protected:
     Kart*             m_owner;              // the kart which released this flyable
@@ -74,6 +78,10 @@ public:
 
                  Flyable     (Kart* kart, CollectableType type, float mass=1.0f);
     virtual     ~Flyable     ();
+    /** Enables/disables adjusting ov velocity depending on height above 
+     *  terrain. Missiles can 'follow the terrain' with this adjustment,
+     *  but gravity will basically be disabled.                          */
+    void         setAdjustZVelocity(bool f) { m_adjust_z_velocity = f; }
     static void  init        (const lisp::Lisp* lisp, ssgEntity *model, 
                               CollectableType type);
     virtual void update      (float);