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Crovea

About to implement A*, have some questions and need tips :)

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Hey! I'm in the process of creating a game engine (who isn't, amirite) for top-down sprite 2d games with alot of units. (such as moba's and RTS games, diablo and scbw was made this way more or less).

So one of the last things i need in my physics subsystem/subengine is pathfinding, where i plan to use the A* algorithm which requires a grid(?).

I plan on using a tilemap for static obstacles (some kind of map loaded from a picture, showing which parts of the map are walkable, possibly using a quadtree)
And my already existing collision detection grid for semi dynamic obstacles (such as buildings, trees, craters, etc)

As mentioned, I use a variable size grid for collision detection. I initialize the grid field size to a size that is atleast the size of the largest units collision box.

[b][i]Q: Which leads me to my first question, wouldn't this kind of grid be too big to also use for pathfinding? (maps will be much larger than a screen)[/i]

[i]Q: Also with the size of the grid fields being variable from game to game, wouldn't that result in different and sometimes bad behavior?[/i][/b]

1. Option would be to split the grid i already have into smaller fields.

[i][b]Q: But with dynamic size grids, how would i go about partitioning it?[/b][/i]

Alternatively, if the existing grid isn't usable i see two other options:

2. Create a new grid for pathfinding with fields always of the same size. (a pretty decent chunk of memory would be required)

3. Try an approach where i dynamically build fields/nodes based on coordinates. The objects could be pulled from a pool to improve performance.

[b][i]Q: Is option 2 actually feasable? or am i missing something essential from A* that makes it unreasonable.[/i][/b]
[b][i]Q: Would option 1 actually be worthwhile despite the memory cost, due to being easier/simpler/faster? [/i][/b]


Any advice, tips or experiences are welcomed [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img]

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Thanks didn't realize it belonged there, i reposted now, assume thats alright! Edited by crovea

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Since you want it in AI, I'll close this one. The new one is [url="http://www.gamedev.net/topic/628363-about-to-implement-a-have-some-questions-and-need-tips/"]here[/url].

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