Added SmokeTrailEffect which renders created particles as single quad or line

strip, in the case of the quad strip the strip is aligned to the be orthogonal with
the eye point.

include/osgParticle/Particle

@@ -28,6 +28,9 @@
 namespace osgParticle
 {
 
+    // forward declare so we can reference it
+    class ParticleSystem;
+
     /**    Implementation of a <B>particle</B>.
         Objects of this class are particles, they have some graphical properties
         and some physical properties. Particles are created by emitters and then placed
@@ -44,6 +47,11 @@ namespace osgParticle
     */
     class OSGPARTICLE_EXPORT Particle {
     public:
+        
+        enum
+        {
+            INVALID_INDEX = -1
+        };
 
         /**
          Shape of particles.
@@ -125,6 +133,18 @@ namespace osgParticle
         
         /// Get the previous angle vector.
         inline const osg::Vec3& getPreviousAngle() const;
+        
+        /// Get the current color
+        inline const osg::Vec4& getCurrentColor() const { return _current_color; }
+
+        /// Get the current alpha
+        inline float getCurrentAlpha() const { return _current_alpha; }
+        
+        /// Get the s texture coordinate of the bottom left of the particle
+        inline const float getSTexCoord() const { return _s_coord; }
+
+        /// Get the t texture coordinate of the bottom left of the particle
+        inline float getTCoord() const { return _t_coord; }
 
         /** Kill the particle on next update
             NOTE: after calling this function, the <CODE>isAlive()</CODE> method will still 
@@ -216,10 +236,26 @@ namespace osgParticle
         /// Get the current (interpolated) polygon size. Valid only after the first call to update().
         inline float getCurrentSize() const;
         
-        // Specify how the particle texture is tiled
+        /// Specify how the particle texture is tiled
         inline void setTextureTile(int sTile, int tTile, int numTiles = 0);
 
-    private:
+        /// Set the previous particle
+        inline void setPreviousParticle(int previous) { _previousParticle = previous; }
+
+        /// Get the previous particle
+        inline int getPreviousParticle() const { return _previousParticle; }
+
+        /// Set the next particle
+        inline void setNextParticle(int next) { _nextParticle = next; }
+
+        /// Get the const next particle
+        inline int getNextParticle() const { return _nextParticle; }
+
+        /// Method for initializing a particles texture coords as part of a connected particle system.
+        void setUpTexCoordsAsPartOfConnectedParticleSystem(ParticleSystem* ps);
+
+    protected:
+    
         Shape _shape;
 
         rangef _sr;
@@ -259,8 +295,8 @@ namespace osgParticle
         float _t_coord;
         
         // previous and next Particles are only used in ConnectedParticleSystems
-        Particle* _previousParticle;
-        Particle* _nextParticle;
+        int _previousParticle;
+        int _nextParticle;
     };
 
     // INLINE FUNCTIONS