Merge pull request #2255 from pacomont/Particles_go_downwind

Particles should go downwind (while windCoefficient >0)

Engine/source/T3D/fx/particleEmitter.cpp

@@ -1390,7 +1390,7 @@ void ParticleEmitter::emitParticles(const Point3F& start,
 
                Point3F a = last_part->acc;
                a -= last_part->vel * last_part->dataBlock->dragCoefficient;
-               a -= mWindVelocity * last_part->dataBlock->windCoefficient;
+               a += mWindVelocity * last_part->dataBlock->windCoefficient;
                //a += Point3F(0.0f, 0.0f, -9.81f) * last_part->dataBlock->gravityCoefficient;
                a.z += -9.81f*last_part->dataBlock->gravityCoefficient; // as long as gravity is a constant, this is faster
 
@@ -1750,7 +1750,7 @@ void ParticleEmitter::update( U32 ms )
    {
       Point3F a = part->acc;
       a -= part->vel * part->dataBlock->dragCoefficient;
-      a -= mWindVelocity * part->dataBlock->windCoefficient;
+      a += mWindVelocity * part->dataBlock->windCoefficient;
       a.z += -9.81f*part->dataBlock->gravityCoefficient; // AFX -- as long as gravity is a constant, this is faster
 
       part->vel += a * t;