Made the skidding parameters configurable in stk_config.data

(and on a per kart basis as well, so each kart can skid differently).


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/trunk/supertuxkart@2676 178a84e3-b1eb-0310-8ba1-8eac791a3b58

data/stk_config.data

@@ -67,6 +67,15 @@
 
    (nitro-power-boost      3 )   ;; increase in engine power, i.e. 1=plus 100%
 
+   ;; Skidding related parameters:
+   (skid-increase        1.05)   ;; Multiplicative increase of skidding factor
+                                 ;; in each frame.
+   (skid-decrease        0.95)   ;; Multiplicative decrease of skidding factor
+                                 ;; in each frame.
+   (skid-max             2.0 )   ;; Maximum skidding factor = maximum increase
+                                 ;; of steering angle.
+   (skid-visual          0.16)   ;; Additional graphical rotation of kart.
+
    ;; Bullet physics attributes
    (brake-factor              2.75 )
    ;; Defines the smallest turn radius at lowest speed (4.64 m at

src/karts/kart.cpp

@@ -762,12 +762,13 @@ void Kart::updatePhysics (float dt)
 
        if(m_controls.jump)
        {
-           m_skidding*= 1.05f;
+           m_skidding*= m_kart_properties->getSkidIncrease();
-           if(m_skidding>2.0f) m_skidding=2.0f;
+           if(m_skidding>m_kart_properties->getMaxSkid())
+               m_skidding=m_kart_properties->getMaxSkid();
        }
        else if(m_skidding>1.0f)
        {
-           m_skidding *= 0.95f;
+           m_skidding *= m_kart_properties->getSkidDecrease();
            if(m_skidding<1.0f) m_skidding=1.0f;
        }
        if(m_skidding>1.0f)
@@ -967,7 +968,8 @@ void Kart::updateGraphics(const Vec3& off_xyz,  const Vec3& off_hpr)
                                  ? getSpeed()*5.0f : 0);
 
     float speed_ratio    = getSpeed()/getMaxSpeed();
-    float offset_heading = getSteerPercent()*0.05f*3.1415926f * speed_ratio * m_skidding*m_skidding;
+    float offset_heading = getSteerPercent()*m_kart_properties->getSkidVisual()
+                         * speed_ratio * m_skidding*m_skidding;
     Moveable::updateGraphics(center_shift, Vec3(offset_heading, offset_pitch, 0));
 }   // updateGraphics
 

src/karts/kart_properties.cpp

@@ -70,6 +70,7 @@ KartProperties::KartProperties() : m_icon_material(0)
         m_max_speed_turn = m_angle_at_max =
         m_rubber_band_max_length = m_rubber_band_force = 
         m_rubber_band_duration = 
+        m_skid_decrease = m_skid_increase = m_skid_visual = m_skid_max =
         m_camera_max_accel = m_camera_max_brake = 
         m_camera_distance = UNDEFINED;
     m_gravity_center_shift   = Vec3(UNDEFINED);
@@ -250,6 +251,11 @@ void KartProperties::getAllData(const lisp::Lisp* lisp)
     lisp->get("rubber-band-force",         m_rubber_band_force        );
     lisp->get("rubber-band-duration",      m_rubber_band_duration     );
 
+    lisp->get("skid-increase",             m_skid_increase            );
+    lisp->get("skid-decrease",             m_skid_decrease            );
+    lisp->get("skid-max",                  m_skid_max                 );
+    lisp->get("skid-visual",               m_skid_visual              );
+
     lisp->getVector("groups",              m_groups                   );
 
     // getVector appends to existing vectors, so a new one must be used to load
@@ -332,6 +338,11 @@ void KartProperties::checkAllSet(const std::string &filename)
     CHECK_NEG(m_rubber_band_max_length,    "rubber-band-max-length"     );
     CHECK_NEG(m_rubber_band_force,         "rubber-band-force"          );
     CHECK_NEG(m_rubber_band_duration,      "rubber-band-duration"       );
+    CHECK_NEG(m_skid_decrease,             "skid-decrease"              );
+    CHECK_NEG(m_skid_increase,             "skid-increase"              );
+    CHECK_NEG(m_skid_max,                  "skid-max"                   );
+    CHECK_NEG(m_skid_visual,               "skid-visual"                );
+
     CHECK_NEG(m_camera_max_accel,          "camera-max-accel"           );
     CHECK_NEG(m_camera_max_brake,          "camera-max-brake"           );
     CHECK_NEG(m_camera_distance,           "camera-distance"            );

src/karts/kart_properties.hpp

@@ -127,6 +127,15 @@ protected:
     float m_upright_tolerance;
     float m_upright_max_force;
 
+    float m_skid_visual;              /**< Additional rotation of 3d model
+                                       *   when skidding. */
+    float m_skid_max;                 /**< Maximal increase of steering when
+                                       *   skidding. */
+    float m_skid_increase;            /**< Skidding is multiplied by this when
+                                       *   skidding to increase to 
+                                       *   m_skid_increase. */
+    float m_skid_decrease;            /**< Skidding is multiplied by this when
+                                       *   not skidding to decrease to 1.0. */
     // Camera related setting
     // ----------------------
     float m_camera_max_accel;         // maximum acceleration of camera
@@ -199,6 +208,16 @@ public:
     float getRubberBandForce        () const {return m_rubber_band_force;        }
     /** Returns the duration a rubber band is active for. */
     float getRubberBandDuration     () const {return m_rubber_band_duration;     }
+    /** Returns additional rotation of 3d model when skidding. */
+    float getSkidVisual             () const {return m_skid_visual;              }
+    /** Returns the maximum factor by which the steering angle can be increased. */
+    float getMaxSkid                () const {return m_skid_max;                 }
+    /** Returns the factor by which m_skidding is multiplied when the kart is 
+     *  skidding to increase it to the maximum. */
+    float getSkidIncrease           () const {return m_skid_increase;            }
+    /** Returns the factor by which m_skidding is multiplied when the kart is 
+     *  not skidding to decrease it back to 1.0f . */
+    float getSkidDecrease           () const {return m_skid_decrease;            }
     const std::vector<float>& 
           getGearSwitchRatio        () const {return m_gear_switch_ratio;        }
     const std::vector<float>&