Added a little jump (duration set in config file) when

starting to skid.


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@10965 178a84e3-b1eb-0310-8ba1-8eac791a3b58

data/stk_config.xml

@@ -185,8 +185,8 @@
           visual="1.0" visual-time="0"
           time-till-bonus="1.0 3.0" 
           bonus-speed="4.5 6.5" bonus-time="3.0 4.0" 
-          post-skid-rotate-factor="1" reduce-turn-min="0.3"
+          post-skid-rotate-factor="1" jump-time="0.4"
-          reduce-turn-max="0.8"/>
+          reduce-turn-min="0.4" reduce-turn-max="0.8"/>
 
     <!-- Slipstream: length: How far behind a kart slipstream works
          collect-time: How many seconds of sstream give  maximum benefit

src/karts/skidding.cpp

@@ -21,7 +21,9 @@
 #include "karts/kart.hpp"
 #include "karts/kart_gfx.hpp"
 #include "karts/kart_properties.hpp"
+#include "modes/world.hpp"
 #include "physics/btKart.hpp"
+#include "tracks/track.hpp"
 
 /** Constructor of the skidding object.
  */
@@ -155,17 +157,29 @@ void Skidding::update(float dt, bool is_on_ground,
     switch(m_skid_state)
     {
     case SKID_NONE: 
-        // If skidding is pressed while the kart is going straight,
+        {
-        // do nothing (till the kart starts to steer in one direction).
+            // If skidding is pressed while the kart is going straight,
-        // Just testing for the sign of steering can result in unexpected
+            // do nothing (till the kart starts to steer in one direction).
-        // beahviour, e.g. if a player is still turning left, but already
+            // Just testing for the sign of steering can result in unexpected
-        // presses right (it will take a few frames for this steering to
+            // beahviour, e.g. if a player is still turning left, but already
-        // actuallu take place, see player_controller) - the kart would skid 
+            // presses right (it will take a few frames for this steering to
-        // to the left. So we test for a 'clear enough' steering direction.
+            // actuallu take place, see player_controller) - the kart would skid 
-        if(!skidding || fabsf(steering)<0.3f) break;
+            // to the left. So we test for a 'clear enough' steering direction.
-        m_skid_state = steering > 0 ? SKID_ACCUMULATE_RIGHT
+            if(!skidding || fabsf(steering)<0.3f) break;
-                                    : SKID_ACCUMULATE_LEFT;
+            m_skid_state = steering > 0 ? SKID_ACCUMULATE_RIGHT
-        m_skid_time  = 0;   // fallthrough
+                : SKID_ACCUMULATE_LEFT;
+            m_skid_time  = 0;   // fallthrough
+
+            // Add a little jump to the kart. Determine the vertical speed 
+            // necessary for the kart to go 0.5*jump_time up (then it needs
+            // the same time to come down again), based on v = gravity * t.
+            // Then use this speed to determine the impulse necessary to 
+            // reach this speed.
+            float v = World::getWorld()->getTrack()->getGravity() 
+                    * 0.5f*m_jump_time;
+            btVector3 imp(0, v / m_kart->getBody()->getInvMass(),0);
+            m_kart->getVehicle()->getRigidBody()->applyCentralImpulse(imp);
+        }
     case SKID_ACCUMULATE_LEFT:
     case SKID_ACCUMULATE_RIGHT:
         {

src/karts/skidding_properties.cpp

@@ -35,6 +35,7 @@ SkiddingProperties::SkiddingProperties()
     m_post_skid_rotate_factor = UNDEFINED;
     m_skid_reduce_turn_min    = UNDEFINED;
     m_skid_reduce_turn_max    = UNDEFINED;
+    m_jump_time               = UNDEFINED;
     m_has_skidmarks           = true;
 
     m_skid_bonus_time.clear();
@@ -58,6 +59,7 @@ void SkiddingProperties::load(const XMLNode *skid_node)
     skid_node->get("bonus-time",             &m_skid_bonus_time        );
     skid_node->get("bonus-speed",            &m_skid_bonus_speed       );
     skid_node->get("time-till-bonus",        &m_skid_time_till_bonus   );
+    skid_node->get("jump-time",              &m_jump_time              );
 }   // load
 
 // ----------------------------------------------------------------------------
@@ -67,15 +69,16 @@ void SkiddingProperties::checkAllSet(const std::string &filename) const
         fprintf(stderr,"Missing default value for '%s' in '%s'.\n",    \
                 strA,filename.c_str());exit(-1);                       \
     }
-    CHECK_NEG(m_skid_increase,              "skid increase"                 );
+    CHECK_NEG(m_skid_increase,           "skid increase"                 );
-    CHECK_NEG(m_skid_decrease,              "skid decrease"                 );
+    CHECK_NEG(m_skid_decrease,           "skid decrease"                 );
-    CHECK_NEG(m_skid_max,                   "skid max"                      );
+    CHECK_NEG(m_skid_max,                "skid max"                      );
-    CHECK_NEG(m_time_till_max_skid,         "skid time-till-max"            );
+    CHECK_NEG(m_time_till_max_skid,      "skid time-till-max"            );
-    CHECK_NEG(m_skid_visual,                "skid visual"                   );
+    CHECK_NEG(m_skid_visual,             "skid visual"                   );
-    CHECK_NEG(m_skid_visual_time,           "skid visual-time"              );
+    CHECK_NEG(m_skid_visual_time,        "skid visual-time"              );
-    CHECK_NEG(m_post_skid_rotate_factor,    "skid post-skid-rotate-factor"  );
+    CHECK_NEG(m_post_skid_rotate_factor, "skid post-skid-rotate-factor"  );
-    CHECK_NEG(m_skid_reduce_turn_min,       "skid reduce-turn-min"          );
+    CHECK_NEG(m_skid_reduce_turn_min,    "skid reduce-turn-min"          );
-    CHECK_NEG(m_skid_reduce_turn_max,       "skid reduce-turn-max"          );
+    CHECK_NEG(m_skid_reduce_turn_max,    "skid reduce-turn-max"          );
+    CHECK_NEG(m_jump_time,               "skid jump-time"                );
 
     if(m_skid_time_till_bonus.size()==0)
         fprintf(stderr, "Warning: no skid time declared, can be ignored.\n");
@@ -105,7 +108,6 @@ void SkiddingProperties::checkAllSet(const std::string &filename) const
 // ----------------------------------------------------------------------------
 void SkiddingProperties::copyFrom(const SkiddingProperties *destination)
 {
-    //memcpy(this, destination, sizeof(SkiddingProperties));
     *this = *destination;
 }   // copyFrom
 

src/karts/skidding_properties.hpp

@@ -59,6 +59,9 @@ protected:
     /** Additional rotation of 3d model when skidding. */
     float m_skid_visual;
 
+    /** Time for a small jump when skidding starts. */
+    float m_jump_time;
+
     /** This factor is used to determine how much the chassis of a kart
     *  should rotate to match the graphical view. A factor of 1 is 
     *  identical, a smaller factor will rotate the kart less (which might