cocos2d for iPhone

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

1. 

   RelicaGames
   Member

   Hi,

   I'm currently working on a small game that shows a view from above the level. So its basically a top down 2d view. Now in this level, I have lots of enemies swarming from right to left, and the idea is to defend as long as possible. But my question is about overlapping enemies. So when enemies get too close, they overlap, which kinda looks weird as you then have enemies walking on each other. So what I'm wondering is what you would think if you saw this in a game? I mean maybe its just expected behaviour for this sort of game? or would you think it just looks bad?

   One solution I've come up with, which I'm not too sure about is for the enemies to check collisions with the others, and to stop for a moment if about to collide. This stops any overlapping, but also means that if there are slow enemies in front, then the fast ones can't get through. I've also thought about trying to give enemies path-finding, but the game slows down enough as it is during the later stages, so I'm just not sure that this would be possible. So I was hoping that someone might have some good ideas to help with this! (Although I guess my choices are limited here, but maybe I'm missing something!)

   Thanks for any replies!

   (Hope I've explained it well enough!)

   Posted 1 year ago #
2. 

   Dragyn
   Member

   If I were working on this, I'd try to implement extremely primitive pathfinding, since a "proper" pathfinding could definitely bog down with a lot of enemies. What I have in mind is something like this:

   Check for forward collision on each update of each enemy. If there is a collision, rotate the enemy's directional vector by a few degrees, either up or down (up if their Y is greater than the player, down if it is less). Try that movement for collisions, and keep incrementing until you find a move that works. To keep the CPU load down, I'd say that each turn is not a degree at a time, but something like 10 degrees at a time. If you reach 80 degrees and no path is found, then let them get stuck behind the mob. This means you would have 8 or so checks per enemy. Increasing the rotation angle would mean you might get by with 3 or 4 angle checks per enemy, which might be tolerable.

   Another way to keep it down is to only check for alternate pathing on a different interval (1 per second?), so they would give the impression of trying to push their way through before they try to go around.

   A completely different approach is to have pre-determined paths for the enemies, which you could define to reduce the crowding. Obviously, this could make gameplay too predictable, but it would definitely be a lighter CPU load.

   Posted 1 year ago #
3. 

   abitofcode
   Moderator

   Use Physics to handle your collisions (box2D or Chipmunk) and switch off gravity

   Posted 1 year ago #
4. 

   RelicaGames
   Member

   Thanks @Dragyn, there's some good ideas there that i'll have to try out! I never actually thought of using a different interval for that!

   @abitofcode, that is something I've thought about, especially since someone's been working on a very nice looking box2D wrapper! So I may do some experimenting with that if the above ideas don't work out too well!! (wishing I had a 2nd gen to test on.. I have a 1st gen, but with my use of blocks, and some troubles I've had getting it to work with plblocks, I'm having to avoid testing too much on there! and my 4th gen runs everything fast anyway!)

   Posted 1 year ago #

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