CODEWITHSUNDEEP
classxnacollision
stav12212
stav12212

Reputation: 21

interaction with objects in xna

I'm new to using xna and I want to make my player collide with with multipe walls from the same class. So I looked around and I understood that the best way for doing that is to create a list of variables containing the walls id's and make a loop that circles them all and then returns the variable of the objects that collide. My question is if there is a faster more efficient way for doing that? I mean if I have like 10000 objects that loop can cause a lot of memory use. Thx in advance

Upvotes: 0

Views: 396

Answers (2)

Madmenyo
Madmenyo

Reputation: 8584

You always want to do the least amount of processing to get the job done. For a tiled 2D game you usually have a 2 dimensional grid. When the player want to walk on a certain tile you can check that tile if it is allowed to walk there. In this case you just have to check a single tile. If you have a lot of NPC's you could divide your map into sections and keep track of in what sections the NPC's are. Now you just have to do collision detection on the enemies within your section.

When you need expensive collision, pixel perfect or polygon collision you should first check if an object is even close with a simple radius float or BoundingSphere only then you go on with more expensive collision detection.

Same goes for pretty much anything, if you have a 100x100 tilemap but only need to draw 20x10 for the screen then you should just render that portion by calculations. In unreal, mappers create invisible boxes, when inside these boxes it only draws a certain part of the map and only checks collision within these boxes. GameDev is all about tricks to make things work smoothly.

Upvotes: 0

joram
joram

Reputation: 153

Option 1) If these 10000 object are walls of a level, then you should probably use some sort of grid (like this very old example: https://en.wikipedia.org/wiki/The_Legend_of_Zelda#mediaviewer/File:Legend_of_Zelda_NES.PNG) With a grid you only have to check collision with adjacent objects, or only with objects that are nearby.

Option 2) If these 10000 objects are enemies or bullets that move more freely, then you could also calculate the distance first and only check for collision if the objects are nearby.

But may I ask why you are using XNA? I used to work with XNA 4.x but in my understanding it is pretty much dead (http://www.computerandvideogames.com/389018/microsoft-email-confirms-plan-to-cease-xna-support). If you're new to XNA, I would advice to use other software to make games (like Unity3D). In Unity3D the hard part of collision detection is done for you (is has standard functions for collision detection) and Unity3D also works with C# (like XNA)

Upvotes: 1

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