58 lines
1.5 KiB
Python
58 lines
1.5 KiB
Python
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import random
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from math import pi, sin, cos, hypot, floor
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class Grid(object):
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def __init__(self, r):
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self.r = r
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self.size = r / 2 ** 0.5
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self.cells = {}
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def points(self):
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return self.cells.values()
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def normalize(self, x, y):
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i = int(floor(x / self.size))
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j = int(floor(y / self.size))
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return (i, j)
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def nearby(self, x, y):
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result = []
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i, j = self.normalize(x, y)
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for p in xrange(i - 2, i + 3):
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for q in xrange(j - 2, j + 3):
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if (p, q) in self.cells:
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result.append(self.cells[(p, q)])
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return result
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def insert(self, x, y):
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for bx, by in self.nearby(x, y):
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if hypot(x - bx, y - by) < self.r:
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return False
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i, j = self.normalize(x, y)
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self.cells[(i, j)] = (x, y)
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return True
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def poisson_disc(x1, y1, x2, y2, r, n):
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x = x1 + (x2 - x1) / 2.0
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y = y1 + (y2 - y1) / 2.0
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active = [(x, y)]
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grid = Grid(r)
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grid.insert(x, y)
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while active:
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ax, ay = random.choice(active)
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for i in xrange(n):
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a = random.random() * 2 * pi
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d = random.random() * r + r
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x = ax + cos(a) * d
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y = ay + sin(a) * d
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if x < x1 or y < y1 or x > x2 or y > y2:
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continue
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if not grid.insert(x, y):
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continue
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active.append((x, y))
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break
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else:
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active.remove((ax, ay))
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return grid.points()
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