Hi all,

I'm using XNA to make an asteroids clone (asteroids meets Geometry Wars, original I know...) and I'm having trouble initiating new waves of asteroids. When an asteroid is destroyed it is removed from the game components list. I basically need something like this:

if(Components.ASTEROIDS.Count == 0)
{

wave += 1

}

I'm just not sure of the syntax...

Any help anyone can offer would be greatly appreciated :D

Thanks!

I personally would have a single object that holds all the asteroids and work with that object, so if you had 500 asteroids, you would still only be adding 1 object to the components list (which would contain all those asteroids in itself).


That being said - I would probably do something like this - somewhat simplified since I dont know how you have your code currently set up, organized etc...but hopefully it can point you in the right direction.

Using a List manager class is good. What you don't want to do is remove and add items to the list. Have a member of the Asteroid class that tells if the asteroid is not destroyed and only draw and calculate collision with the ones that aren't destroyed.

agreed with jim, I usually would have (in this example) the asteroids having a property of IsValid, IsAlive, something to that effect to indicate if it should be included in drawing, collision, and also the if their are any asteroids left for the current wave - so that section would be adjusted a bit  to something like this for example

Okay, thanks Jim and squidpunch :) This is my first game using C#/XNA, so at the minute all the code for my collision detection is held in game1 (which I now realise is a sloppy way of doing things..), would it still work okay using the asteroid manager in this way, or would I have to transfer the collision detection code somewhere else (in the Asteroid Manager class?). I also have mini-asteroids the branch off when a regular asteroid is shot... how should I deal with those? =/


This is my collision code, doGameLogic detects collision between the player and an asteroid, and ShotAstCollide detects collision between a bullet and an asteroid(and mini-asteroid):

Here is RemoveAllAsteroids:



I already have a boolean in the Asteroid called "hit" this can do the same thing as "IsAlive" yeah?

Sorry, I'm not quite 100% on how to inegrate the asteroid manager with my current code.
Obviously I'd change everything to do with removing asteroids from the components list but could I keep the basic collision code the same?

The code I currently use to load the asteroids at the start of the game is this:


Thanks for the help so far guys :)

If you are going to take the direction of having a manager class to handle your asteroids then I yeah I would suggest refactoring your collision logic into the manager, you still might end up with some code in the game class to interface with your player (unless your asteroid manager has some sort of interaction with the your player object)

You could also refactor the mini-asteroid branching into the asteroid manager as well.

you could modify the game class a bit to do the collision detection - instead of looping through the game components you could loop through the asteroidmanagers list of asteroids.

or you could possibly take it a step further and push all the collision into the asteroid manager - of course in that case, you would need to have a way to interface with your player, and the bullet objects...etc

I could probably slap together some code to show you how to migrate to an asteroid manager - but you would learn a ton more by approaching the problem yourself, and seeking help if needed along the way.  You can work in steps too, you dont have to go all out to start.  So things like keeping the collision detection in the game class to start, and then if you feel like pushing it off to the manager at a later time if you wish :)

Just think of what you are trying to do and work down the list

Okay, I've got the AsteroidManager going, the asteroids in it now draw, move and collide with the player. I'm having some trouble with sorting the collision with shots however. I tried using a shot manager too, but got a bit lost, so I decided to use my Game1 code for the time being, so I changed it like you said to test against each asteroid in my Asteroid Manager. When I do this I get the following error:

"Error 1 foreach statement cannot operate on variables of type 'Astrevolution.AsteroidManager' because 'Astrevolution.AsteroidManager' does not contain a public definition for 'GetEnumerator'"

I've searched the error and it seem like a pretty complex thing to fix :S

Thanks for the advice squidpunch, has been very helpful thus far :)

You can only use foreach with an IEnumerable instance - it sounds like your manager does not implement that interface. From the code above I'm assuming that you have a List within your AsteroidManager, which will be an IEnumerable. So you likely want:

  foreach(Asteroidasteriod in AsteroidManager.YourList)
  {
  }

This assumes that your list is publicly available outside the manager class (which it may not be). Another option would be to implement the IEnumerable interface in your manager, simply returning the List.GetEnumerator - this is more complicated and depends on the design of your code.

That did the trick! Thank you very much :) My game is nearly finished now.