[C++, DX9] Body Collision Callback?

[Ripiz]

I noticed there's function NewtonMaterialSetCollisionCallback() but it works only if one material collides other material and will call function only between these two specific materials. Is there a way to make callback for specific body? Like, if it's missile and I want to make it explode on contact, I don't care if it'll collide wood, metal, or blackhole, I just want it to explode, how do I do that?

Thanks in advance.

[Ripiz]

I meant which Newton function to use to set such callback to Explode() function, not how to make explosion

void Explode(/* some params */){
}

[JernejL]

inside NewtonContactsProcess use NewtonJointGetBody0 and NewtonJointGetBody1 to see what bodies touched, then do your "explosion".

[Ripiz]

I set material on my missile:

Code: Select all

NewtonBodySetMaterialGroupID (body, NewtonFireballMaterial);

My callback:

Code: Select all

void collisionFireballCallback(const NewtonJoint* contactJoint, dFloat timestep, int threadIndex){
   extern int NewtonFireballMaterial;
   extern vector<ParticleEmitter*> particleEmitters;
   extern NewtonWorld *world;
   NewtonBody *body = 0;


   body = NewtonJointGetBody0(contactJoint);
   if(NewtonBodyGetMaterialGroupID(body) == NewtonFireballMaterial){
      ParticleEmitter *emitter = (ParticleEmitter*)NewtonBodyGetUserData(body);
      for(unsigned int i = 0; i < particleEmitters.size(); i++){
         if(particleEmitters[i] == emitter){
            particleEmitters.erase(particleEmitters.begin() + i);
            NewtonDestroyBody(world, body);
            particleEmitters.push_back(new ParticleEmitter(emitter->loc, Explode, 0.5f));
            delete emitter;
            break;
         }
      }
   }

   body = NewtonJointGetBody1(contactJoint);
   if(NewtonBodyGetMaterialGroupID(body) == NewtonFireballMaterial){
      ParticleEmitter *emitter = (ParticleEmitter*)NewtonBodyGetUserData(body);
      for(unsigned int i = 0; i < particleEmitters.size(); i++){
         if(particleEmitters[i] == emitter){
            particleEmitters.erase(particleEmitters.begin() + i);
            NewtonDestroyBody(world, body);
            particleEmitters.push_back(new ParticleEmitter(emitter->loc, Explode, 0.5f));
            delete emitter;
            break;
         }
      }
   }
}

Problem is, that if I call 'delete emitter;' inside callback it causes some weird heap error and application crashes. I have suspicions that it's Newton problem, because I delete ParticleEmitter in other places too but it's all fine if I comment out both 'delete emitter;' lines in this callback. Anyone have idea how to fix this?

[Julio Jerez]

if you are running a dll and you try to delete an object from a callback comming from the DLL,
but that object was not allocated by that DLL, you will have a heap corruption.

rule 101, of programming with DLL is delete and alloc in the same dll Module,

you can place the object you wna to delete into a queuse and then deleted it afte teh neton Update.