school project

[Notthebbq]

hi, my group has a semester long project to make a game in python. were doing a TD and i wanted to know if you could tell us anyway to make creeps go along any created path like normal internet TD like desktop where the creeps will seek out a new path or go around towers you place down

[apython1992]

Typically path collision detection involves using a color key; you can tell if an object is on the path by finding out the color of the pixels beneath it. Here is a good tutorial on this: http://www.xnadevelopment.com/tutorials/theroadnottaken/theroadnottaken.shtml . The tutorial was written for XNA game developers (C#), but you should be able to grab the concepts out of it and translate to Python. Are you using Pygame?

[Tony]

apython1992 @ Thu Mar 31, 2011 12:23 pm wrote:

Typically...

It is not, as using the same buffer for both collision information and graphics is bad news. It either forces simple and _very_ restricted animations, or opens up the possibility of bugs where a collision is not detected when a bullet animation just happened to fly over a tower at the right frame.

A much better idea is to just have an array/grid/tile-map.

Pathfinding itself could use something like A* http://en.wikipedia.org/wiki/A*_search_algorithm

[apython1992]

Well, as far as I understand it, the color key information for the path would be on a separate back buffer. And yeah, typically is probably not true, it's just the only way I've heard it done OP: Take Tony's advice over mine, using tile-based paths is probably a much better option.

[Insectoid]

In a tower-defense game you really don't need pathfinding unless you want to make a level creator or something. You can easily create a list of waypoints that the creeps travel to. Once you have that, it's as easy as moving toward awaypoint.

If you simply must use AI pathfinding, you can use color detection as mentioned above. Just draw your black/white (or w/e) map to the buffer, do your checks, then re-draw your detailed map to the buffer before outputting it to the screen (I dunno if you can manually double-buffer and update in Python; it's quite trivial in Turing but I've never done graphics in anything else).

[Notthebbq]

apython1992, yes we are using pygame to make this

[apython1992]

Cool. Do you understand Tony's method? This would be the simplest way to represent a path, I would think.

[Notthebbq]

yes we understand Tony, our original plan was to use premade maps and just use, mind blank, point movement. like left to right A -- B and top to bottom B -- C. i was just looking to see how you can do an open map path movement.