44 lines
No EOL
1.5 KiB
Python
44 lines
No EOL
1.5 KiB
Python
"""McRogueFace - Dijkstra Distance Maps (multi)
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Documentation: https://mcrogueface.github.io/cookbook/grid_dijkstra
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Repository: https://github.com/jmccardle/McRogueFace/blob/master/docs/cookbook/grid/grid_dijkstra_multi.py
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This code is extracted from the McRogueFace documentation and can be
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run directly with: ./mcrogueface path/to/this/file.py
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"""
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# Cache Dijkstra maps when possible
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class CachedDijkstra:
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"""Cache Dijkstra computations."""
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def __init__(self, grid):
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self.grid = grid
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self.cache = {}
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self.cache_valid = False
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def invalidate(self):
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"""Call when map changes."""
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self.cache = {}
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self.cache_valid = False
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def get_distance(self, from_x, from_y, to_x, to_y):
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"""Get cached distance or compute."""
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key = (to_x, to_y) # Cache by destination
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if key not in self.cache:
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self.grid.compute_dijkstra(to_x, to_y)
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# Store all distances from this computation
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self.cache[key] = self._snapshot_distances()
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return self.cache[key].get((from_x, from_y), float('inf'))
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def _snapshot_distances(self):
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"""Capture current distance values."""
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grid_w, grid_h = self.grid.grid_size
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distances = {}
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for x in range(grid_w):
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for y in range(grid_h):
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dist = self.grid.get_dijkstra_distance(x, y)
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if dist != float('inf'):
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distances[(x, y)] = dist
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return distances |