Add a new particle effect. Maybe usefull for another track :)

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@11717 178a84e3-b1eb-0310-8ba1-8eac791a3b58

data/gfx/swampDriving.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0"?>
+<particles emitter="box" box_x="0.75" box_y="0.75" box_z="0.75">
+
+    <spreading angle="90"       />
+    
+    <velocity  x="0.000"
+               y="0.009"
+               z="0.000"         />
+    
+    <material  file="water-splash.png"  />
+    
+    <!-- Amount of particles emitted per second -->
+    <rate      min="100"
+               max="150"
+               decay_rate="20"   />
+    
+    <!-- Minimal and maximal lifetime of a particle, in milliseconds. -->
+    <lifetime  min="1200"
+               max="1600"         />
+    
+    <!-- Size of the particles -->
+    <size      min="0.20"
+               max="0.50"        />
+
+    <color     min="255 255 255"
+               max="255 255 255" />
+
+    <!-- How much time in milliseconds before the particle is fully faded out  -->
+    <fadeout   time="500"        />
+
+    <gravity   strength="-0.01"
+               only-force-time="1000" />
+</particles>