anyone know about terrain material showdust emitter

new TerrainMaterial()
{
   internalName = "dirt_grass";
   diffuseMap = "art/terrains/Example/dirt_grass";
   detailMap = "art/terrains/Example/dirt_grass_d";
   detailSize = "5";
   detailDistance = "300";
   isManaged = "1";
   detailBrightness = "1";
   Enabled = "1";
   diffuseSize = "200";
   normalMap = "art/terrains/new Example/dirt_normal";
};

new Material( DustTerrain )
{
   ShowDust = true;           // Show dust particles.
};

new Material( dirt_grass01 : DustTerrain )
{
   MapTo = "dirt_grass";
};

// Emit footpuffs.

            if( rInfo.t <= 0.5 && mWaterCoverage == 0.0
                && material && material->mShowDust )
            {
               // New emitter every time for visibility reasons
               ParticleEmitter * emitter = new ParticleEmitter;
               emitter->onNewDataBlock( mDataBlock->footPuffEmitter );

               ColorF colorList[ ParticleData::PDC_NUM_KEYS];

               for( U32 x = 0; x < getMin( Material::NUM_EFFECT_COLOR_STAGES, ParticleData::PDC_NUM_KEYS ); ++ x )
                  colorList[ x ].set( material->mEffectColor[ x ].red,
                                      material->mEffectColor[ x ].green,
                                      material->mEffectColor[ x ].blue,
                                      material->mEffectColor[ x ].alpha );
               for( U32 x = Material::NUM_EFFECT_COLOR_STAGES; x < ParticleData::PDC_NUM_KEYS; ++ x )
                  colorList[ x ].set( 1.0, 1.0, 1.0, 0.0 );

               emitter->setColors( colorList );
               if( !emitter->registerObject() )
               {
                  Con::warnf( ConsoleLogEntry::General, "Could not register emitter for particle of class: %s", mDataBlock->getName() );
                  delete emitter;
                  emitter = NULL;
               }
               else
               {
                  emitter->emitParticles( pos, Point3F( 0.0, 0.0, 1.0 ), mDataBlock->footPuffRadius,
                     Point3F( 0, 0, 0 ), mDataBlock->footPuffNumParts );
                  emitter->deleteWhenEmpty();
               }
            }