cocos2d for iPhone

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

1. 

   Korki696
   Member

   Hey so ive been working with Shivaz awesome code for collision detection using chipmunk and ive been going throught all different kinds of methods on how i can make it so the sprites wont go through eachother. i found that possibly i could use something like this:

   PlayerSprite *player1Sprite = a->data;
   PlayerSprite *player2Sprite = b->data;

   if( player1Sprite) {
   float oldPositionx = a->body->p.x;
   float oldPositiony = a->body->p.y;

   [player1Sprite setPosition:ccp(oldPositionx, oldPositiony)];
   }

   This does work but the problem im having is that after that happens i cant move the sprite anymore as long as its colliding since its always set to the old position. If i were to move the sprite it collided with they can all move again. So my question is how can i make it so i can move it even if it is colliding?
   Thanks
   -Lars

   Posted 2 years ago #
2. 

   pabloruiz55
   Member

   Hi!
   What you should do then is move the object a pixel away from the object it collided with, so in the next step they are not colliding...

   This can be a little tricky since you have to detect from where they are colliding in order to move the object accordingly.

   -Basicly what you would have to do is foreach moving object check if in the next step they would collide with something.
   -Then if an object will collide move it to the nearest point before where it would collide ( it would be obstacle's rectagle +1 or -1 depending from where you are colliding)

   You can find more info by googling it... sometime ago i could not find any example written for iphone, but maybe you can replicate something from c# + XNA, i have found many good tutorials for that in the past.

   Posted 2 years ago #
3. 

   Korki696
   Member

   Hey,
   So i get what your saying and looked into it a little and i found the mtd (minimum translation distance) the problem is all of these sprites rotate as you move them to follow your finger. Which would mean i probably have to figure out the rotation of both sprites and then move it accordingly. right?
   Thanks
   -Lars

   Posted 2 years ago #
4. 

   pabloruiz55
   Member

   Mhh i am not sure... i used this method once for a simple platformer game, i only checked collision between players,enemies and the map, and none of them had any rotation applied...

   If you don't need a precise collition, maybe you could just check if in the next movement there will be collition and if there would be, just don't move the object anymore.

   If it was for the collition of a player and a wall the result would be that sometimes the player would stop some pixels BEFORE the wall, and it would look awful... It also depends on how much you are moving the object per frame.

   Posted 2 years ago #

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