Tweak fire on zippers to actually work. A side effect is that now when you use nitro and stop using it, instead of stopping immediately it fades out over a second or two. Tell me if you love or hate :)

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@9458 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/graphics/particle_emitter.cpp

@@ -258,6 +258,13 @@ void ParticleEmitter::setCreationRate(float f)
     }
 }   // setCreationRate
 
+//-----------------------------------------------------------------------------
+
+int ParticleEmitter::getCreationRate()
+{
+    return m_emitter->getMinParticlesPerSecond();
+}
+
 //-----------------------------------------------------------------------------
 /** Sets the position of the particle emitter.
  *  \param pos The position for the particle emitter.

src/graphics/particle_emitter.hpp

@@ -74,6 +74,7 @@ public:
     virtual     ~ParticleEmitter();
     virtual void update         ();
     void         setCreationRate(float f);
+    int          getCreationRate();
     
     void         setPosition(const Vec3 &pos);
     

src/karts/kart.cpp

@@ -1917,9 +1917,11 @@ void Kart::updateGraphics(float dt, const Vec3& offset_xyz,
             const float rate    = fabsf(getSpeed())/m_kart_properties->getMaxSpeed();
             assert(rate >= 0.0f); // allow for rounding errors...
             //assert(rate <= 2.0f); // max speed is not always respected it seems...
-            m_nitro->setCreationRate(m_controls.m_nitro && isOnGround() && 
-                                     m_collected_energy>0
-                                     ? (min_rate + rate*(max_rate - min_rate)) : 0);
+            float calculated_rate = m_controls.m_nitro && isOnGround() &&  m_collected_energy > 0
+                                    ? (min_rate + rate*(max_rate - min_rate)) : 0;
+            
+            // the std::max call is there to let nitro fade out smoothly instead of stopping sharply
+            m_nitro->setCreationRate(std::max(calculated_rate, m_nitro->getCreationRate() - dt*800.0f));
             
             // the emitter box should spread from last frame's position to the current position
             // if we want nitro to be emitted in a smooth, continuous flame and not in blobs