111 lines
3.9 KiB
Python
Executable file
111 lines
3.9 KiB
Python
Executable file
# SPDX-FileCopyrightText: 2020 Carter Nelson for Adafruit Industries
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#
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# SPDX-License-Identifier: MIT
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class MatrixSand:
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"""Class to simulate simplified sand physics."""
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def __init__(self, width, height):
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self._width = width
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self._height = height
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self._grains = [False] * width * height
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def __getitem__(self, value):
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if isinstance(value, tuple):
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value = value[0] + self._width * value[1]
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return self._grains[value]
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def __setitem__(self, value, key):
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if isinstance(value, tuple):
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value = value[0] + self._width * value[1]
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self._grains[value] = key
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def _side_count(self, upside_down=False):
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left = right = 0
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for x in range(self._width):
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for y in range(self._height):
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if x != y and self[x, y]:
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if x > y:
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right += 1
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else:
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left += 1
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if upside_down:
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return right, left
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else:
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return left, right
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def iterate(self, acceleration):
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"""Update sand based on supplied acceleration tuple. Returns True if
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any motion occurred, otherwise False."""
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#pylint: disable=too-many-locals,too-many-nested-blocks,too-many-branches
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ax, ay, az = acceleration
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# if z dominates, don't do anything
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if abs(az) > abs(ax) and abs(az) > abs(ay):
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return False
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# unit vectors for accelo
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ix = iy = 0
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if abs(ax) > 0.01:
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ratio = abs(ay / ax)
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if ratio < 2.414: # tan(67.5deg)
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ix = 1 if ax > 0 else -1
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if ratio > 0.414: # tan(22.5deg)
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iy = 1 if ay > 0 else -1
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else:
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iy = 1 if ay > 0 else -1
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# buffer
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new_grains = self._grains[:]
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# flag to indicate change
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updated = False
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# loop through the grains
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for x in range(self._width):
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for y in range(self._height):
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# is there a grain here?
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if self[x, y]:
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moved = False
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# compute new location
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newx = x + ix
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newy = y + iy
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# bounds check
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newx = max(min(self._width-1, newx), 0)
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newy = max(min(self._height-1, newy), 0)
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# wants to move?
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if x != newx or y != newy:
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moved = True
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# is it blocked?
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if new_grains[newx + self._width * newy]:
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# can we move diagonally?
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if not new_grains[x + self._width * newy] and \
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not new_grains[newx + self._width * y]:
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# can move either way
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# move away from fuller side
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left, right = self._side_count(ax < 0 and ay < 0)
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if left >= right:
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newy = y
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elif right > left:
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newx = x
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elif not new_grains[x + self._width * newy]:
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# move in y only
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newx = x
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elif not new_grains[newx + self._width * y]:
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# move in x only
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newy = y
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else:
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# nope, totally blocked
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moved = False
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# did it move?
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if moved:
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new_grains[x + self._width * y] = False
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new_grains[newx + self._width * newy] = True
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updated = True
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# did things change?
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if updated:
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self._grains = new_grains
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return updated
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