UnrealScript Game Programming Cookbook

Weapons

182

This would be an excellent time to add more functionality to this, such as having the

mesh fracture into pieces. UDK offers a great tool for doing exactly this, although it's

beyond the scope of this recipe, so we'll pass over it for the moment.

We then trigger our sound effect and particle effect for the explosion. The current

particle effect is great, as it allows for a slow roasting flame along with smoke to

continue where the barrel was for quite some time after detonation. The spawning

of our physics mesh follows shortly after, and this kinetic actor is what allows the

barrel to be moved and manipulated within the world.

Finally, we call RespawnTime, which is actually defined in the default properties.

The barrel will respawn after a set number of seconds defined there.

4. What good is an explosive barrel if it doesn't explode when hit? We need to create
   a way for our barrel to explode when it takes damage, so the next function does
   exactly that.
   /****
   
   
   • Called when the object is shot or damaged
     ****/
     simulated function TakeDamage
     (int DamageAmount, Controller EventInstigator, vector
     HitLocation, vector Momentum, class DamageType,
     optional TraceHitInfo HitInfo, optional Actor DamageCauser)
     {
     if(!bDestroyed && bDestroyOnDmg)
     {
     Explode();
     }
     }
   
   
   
   

We check to see if our barrel is not destroyed and if it is to be destroyed when taking

damage. If both are true, call Explode()!

5. That's not the only way to detonate our barrel though. We also have the option to
   have it explode if it is touched, either by a vehicle or a pawn. Let's add that function:
   /****
   
   
   • Called when a pawn/vehicle touches it
     ****/
     simulated function Touch(Actor Other, PrimitiveComponent
     OtherComp, vector HitLocation, vector HitNormal)
     {
     // Ignore if destroyed.
     if(bDestroyed)
     {
     return;
     }