Nitro and skidding gfx improvements

- skidding effect shouldn't depend on height of the kart
 - workaround for karts which don't have nitro emitters

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@14202 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/karts/abstract_kart.cpp

@@ -55,6 +55,7 @@ AbstractKart::AbstractKart(const std::string& ident,
     m_kart_length = m_kart_model->getLength();
     m_wheel_graphics_position = m_kart_model->getWheelsGraphicsPosition();
     m_nitro_emitter_position = m_kart_model->getNitroEmittersPositon();
+    m_has_nitro_emitter = m_kart_model->hasNitroEmitters();
 }   // AbstractKart
 
 // ----------------------------------------------------------------------------

src/karts/abstract_kart.hpp

@@ -55,6 +55,8 @@ private:
     const Vec3* m_wheel_graphics_position;
     /** The position of all nitro emitters in the 3d model */
     const Vec3* m_nitro_emitter_position;
+    /** True if kart has nitro emitters */
+    bool m_has_nitro_emitter;
 
     /** Index of kart in world. */
     unsigned int m_world_kart_id;
@@ -161,6 +163,10 @@ public:
     /** Returns the position of a nitro emitter relative to the kart */
     const Vec3& getNitroEmitterPosition(int i) const
                 {assert(i>=0 && i<2); return m_nitro_emitter_position[i];}
+    // ------------------------------------------------------------------------
+    /** Returns true if kart has nitro emitters */
+    const bool hasNitroEmitter() const
+                {return m_has_nitro_emitter;}
 
     // ========================================================================
     // Emergency animation related functions.

src/karts/kart_gfx.cpp

@@ -50,13 +50,16 @@ KartGFX::KartGFX(const AbstractKart *kart)
     
     
     */
-    Vec3 rear_left(kart->getWheelGraphicsPosition(3).toIrrVector().X, (kart->getKartHeight()-0.6f)*0.35f,
-                        kart->getWheelGraphicsPosition(3).toIrrVector().Z);
-    Vec3 rear_right(kart->getWheelGraphicsPosition(2).toIrrVector().X, (kart->getKartHeight()-0.6f)*0.35f,
-                        kart->getWheelGraphicsPosition(2).toIrrVector().Z);
+    Vec3 rear_left(kart->getWheelGraphicsPosition(3).toIrrVector().X, 0.05f,
+                        kart->getWheelGraphicsPosition(3).toIrrVector().Z-0.1f);
+    Vec3 rear_right(kart->getWheelGraphicsPosition(2).toIrrVector().X, 0.05f,
+                        kart->getWheelGraphicsPosition(2).toIrrVector().Z-0.1f);
 
     Vec3 rear_center(0, kart->getKartHeight()*0.35f,
                        -kart->getKartLength()*0.35f);
+                       
+    Vec3 rear_nitro_center(0, kart->getKartHeight()*0.15f,
+                       -kart->getKartLength()*0.1f);
 
     // FIXME Used to match the emitter as seen in blender
     const float delta = 0.6f;
@@ -67,6 +70,8 @@ KartGFX::KartGFX(const AbstractKart *kart)
     Vec3 rear_nitro_left(kart->getNitroEmitterPosition(1).toIrrVector().X,
                           kart->getNitroEmitterPosition(1).toIrrVector().Y,
                           kart->getNitroEmitterPosition(1).toIrrVector().Z + delta);
+    if (!kart->hasNitroEmitter())
+        rear_nitro_right = rear_nitro_left = rear_nitro_center;
 
     // Create all effects. Note that they must be created
     // in the order of KartGFXType.

src/karts/kart_model.cpp

@@ -135,13 +135,14 @@ void KartModel::loadInfo(const XMLNode &node)
     }
     
     m_nitro_emitter_position[0] = Vec3 (0,0.1f,0);
-
     m_nitro_emitter_position[1] = Vec3 (0,0.1f,0);
+    m_has_nitro_emitter = false;
 
     if(const XMLNode *nitroEmitter_node=node.getNode("nitro-emitter"))
     {
         loadNitroEmitterInfo(*nitroEmitter_node, "nitro-emitter-a", 0);
         loadNitroEmitterInfo(*nitroEmitter_node, "nitro-emitter-b", 1);
+        m_has_nitro_emitter = true;
     }
 
     if(const XMLNode *hat_node=node.getNode("hat"))
@@ -231,6 +232,7 @@ KartModel* KartModel::makeCopy()
     
     km->m_nitro_emitter_position[0] = m_nitro_emitter_position[0];
     km->m_nitro_emitter_position[1] = m_nitro_emitter_position[1];
+    km->m_has_nitro_emitter = m_has_nitro_emitter;
     
     for(unsigned int i=0; i<4; i++)
     {

src/karts/kart_model.hpp

@@ -120,6 +120,9 @@ private:
     /** The position of the nitro emitters */
     Vec3          m_nitro_emitter_position[2];
 
+    /** True if kart has nitro emitters */
+    bool          m_has_nitro_emitter;
+
     /** Minimum suspension length. If the displayed suspension is
      *  shorter than this, the wheel would look wrong. */
     float         m_min_suspension[4];
@@ -214,6 +217,10 @@ public:
     const Vec3* getNitroEmittersPositon() const
                 {return m_nitro_emitter_position;}
     // ------------------------------------------------------------------------
+    /** Returns true if kart has nitro emitters */
+    const bool hasNitroEmitters() const
+                {return m_has_nitro_emitter;}
+    // ------------------------------------------------------------------------
     /** Returns the length of the kart model. */
     float getLength                 () const {return m_kart_length;      }
     // ------------------------------------------------------------------------