the astar library is working fine

Nico on 2006/09/05 01:40 of Nicolas Palumbo

Was my fault, when i see the Demo, in a visual way it seems to be wrong because it work in a different way when finds a path under or over a diagonal wall, but it seems to be only an ilussion because of the way the map is draw, sorry for the time, thanks

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Comments

RB[0] on 2006/09/06 01:05:

But if you want to move diagonally here is a hack that will count diagonal movements as just as expensive as normal movements:

Line 154 of AStar
change the following code block to this:

n = self._handleNode(cl.x+1,cl.y,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x-1,cl.y,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x,cl.y+1,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x,cl.y-1,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x+1,cl.y+1,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x-1,cl.y+1,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x-1,cl.y-1,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x+1,cl.y+1,curnode,dl.x,dl.y)
if n: result.append(n)

Instead of this:

n = self._handleNode(cl.x+1,cl.y,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x-1,cl.y,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x,cl.y+1,curnode,dl.x,dl.y)
if n: result.append(n)
n = self._handleNode(cl.x,cl.y-1,curnode,dl.x,dl.y)
if n: result.append(n)


Then AStar will return diagonal nodes too, instead of just regular ones.

RB[0] on 2006/09/06 01:32:

whoops, the secong to last line of the hack should look like this:

n = self._handleNode(cl.x+1,cl.y-1,curnode,dl.x,dl.y)
meaning that cl.y should -= 1 not += 1

Sorry about that

richard on 2006/09/06 01:44:

I think this is neater: 
    def getAdjacentNodes(self, curnode, dest):
        """MUST BE IMPLEMENTED"""
        result = []

        cl = curnode.location
        dl = dest

        for xm in range(-1,2):
            for ym in range(-1,2):
                if xm == ym == 0: continue
                n = self._handleNode(cl.x + xm,cl.y + ym,curnode,dl.x,dl.y)
                if n: result.append(n)

        return result

richard on 2006/09/06 01:45:

Or, the slightly-faster: 
        for xm in (-1, 0, 1):
            for ym in range(-1, 0, 1):

richard on 2006/09/06 01:59:

Clearly that second line shouldn't have range in it :)