44 lines
1.5 KiB
Python
44 lines
1.5 KiB
Python
|
"""McRogueFace - Dijkstra Distance Maps (multi)
|
||
|
|
|
||
|
|
Documentation: https://mcrogueface.github.io/cookbook/grid_dijkstra
|
||
|
|
Repository: https://github.com/jmccardle/McRogueFace/blob/master/docs/cookbook/grid/grid_dijkstra_multi.py
|
||
|
|
|
||
|
|
This code is extracted from the McRogueFace documentation and can be
|
||
|
|
run directly with: ./mcrogueface path/to/this/file.py
|
||
|
|
"""
|
||
|
|
|
||
|
|
# Cache Dijkstra maps when possible
|
||
|
|
class CachedDijkstra:
|
||
|
|
"""Cache Dijkstra computations."""
|
||
|
|
|
||
|
|
def __init__(self, grid):
|
||
|
|
self.grid = grid
|
||
|
|
self.cache = {}
|
||
|
|
self.cache_valid = False
|
||
|
|
|
||
|
|
def invalidate(self):
|
||
|
|
"""Call when map changes."""
|
||
|
|
self.cache = {}
|
||
|
|
self.cache_valid = False
|
||
|
|
|
||
|
|
def get_distance(self, from_x, from_y, to_x, to_y):
|
||
|
|
"""Get cached distance or compute."""
|
||
|
|
key = (to_x, to_y) # Cache by destination
|
||
|
|
|
||
|
|
if key not in self.cache:
|
||
|
|
self.grid.compute_dijkstra(to_x, to_y)
|
||
|
|
# Store all distances from this computation
|
||
|
|
self.cache[key] = self._snapshot_distances()
|
||
|
|
|
||
|
|
return self.cache[key].get((from_x, from_y), float('inf'))
|
||
|
|
|
||
|
|
def _snapshot_distances(self):
|
||
|
|
"""Capture current distance values."""
|
||
|
|
grid_w, grid_h = self.grid.grid_size
|
||
|
|
distances = {}
|
||
|
|
for x in range(grid_w):
|
||
|
|
for y in range(grid_h):
|
||
|
|
dist = self.grid.get_dijkstra_distance(x, y)
|
||
|
|
if dist != float('inf'):
|
||
|
|
distances[(x, y)] = dist
|
||
|
|
return distances
|