[ofxBox2D] - How to get particle/object position after collision

beginners
#1

Hi folks, I asked this question in the addons page (github), the only response was mine so far.

I am trying to get the particle coordinates to do something if they are between certain boundaries.
The way I am doing it is as follows, I don’t know if it’s the best way to do it, (it seems to work):

    void testApp::contactStart(ofxBox2dContactArgs &e) {
    	if(e.a != NULL && e.b != NULL) {
    		
    		if(e.a->GetType() == b2Shape::e_edge && e.b->GetType() == b2Shape::e_circle) {

                        //some checks and sentences I do


                         ofVec2f p;

                        const b2Transform& xf = e.b->GetBody()->GetTransform();
                        b2Vec2 pos      = e.b->GetBody()->GetLocalCenter();
                        b2Vec2 b2Center = b2Mul(xf, pos);
                        p = worldPtToscreenPt(b2Center);
                        cout << "p.x " << (int)p.x << " p.y " << (int)p.y << endl;

                        if (p.y < sp->pGround1.y - 25)  // menos restrictivo
                        {
                            bData->bHit = true;
                            sound[bData->soundID].play();
                        }

    			}
    		}
    	}

Thanks for any suggestion, cheers!