cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   y2kreddy
   Member

   Hi Developers,

   i am using spacemanager and i want to calculate the force with which the objects collide so that i can adjust the sounds and appropirate spirtes depending on the damage. can some one tell me how to calculate the forces. here is the code i got on this site.
   

   if(!cpArbiterIsFirstContact(arb)) return;
   
   cpFloat impulse = cpvlength(cpArbiterTotalImpulse(arb));
   
   float volume = MIN(impulse/500.0f, 1.0f);
   NSLog(@"impulse is :%f",volume);
   
   NSLog(@" impluse x:%f y:%f", cpArbiterTotalImpulse(arb).x , cpArbiterTotalImpulse(arb).y);
     if(volume > 0.05f){
         [SimpleSound playSoundWithVolume:volume];
     }

   i have this in my POSTSOLVE method.i tried it in BEGIN aswell and all it prints is 0. i went through this site and found that i needs to do this.
   smgr.space->elasticIterations = smgr.space->iterations;

   even after doing the above , sometimes i get 1 and some times it says "nan". is there something basic i need to know?

   Thanks

   Posted 1 year ago #
2. 

   mobilebros
   Moderator

   I thought I remembered slembcke saying there was some issue with that... but it sounds like you did the suggested fix; I wonder if the newest chipmunk still has this issue.

   Posted 1 year ago #
3. 

   y2kreddy
   Member

   after adding

   'smgr.space->elasticIterations = smgr.space->iterations;'

   to my code , i almost always get 0, but very few times i get 1 and very few times i get "nan", Please help me with this, how can i get an intermediate number like .9 or .8 .2 something like that.

   Posted 12 months ago #
4. 

   y2kreddy
   Member

   putting 'smgr.space->elasticIterations = 0;'

   has solved my issue. i am getting the impulse values now.

   Posted 11 months ago #

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