66 lines
1.4 KiB
Python
66 lines
1.4 KiB
Python
import math
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ZERO = (0, 0)
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def dot(x1, y1, x2, y2):
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"""Returns the dot product of two vectors."""
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return (x1 * x2) + (y1 * y2)
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def length(x, y):
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"""Returns the magnitude of a vector."""
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return math.sqrt((x * x) + (y * y))
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def normalize(x, y):
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"""Returns the unit vector pointed in the same direction as [x, y]."""
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_len = length(x, y)
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return x / _len, y / _len
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def lnormal(x, y):
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"""Returns the left-hand normal of a vector."""
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return -y, x
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def rnormal(x, y):
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"""Returns the right-hand normal of a vector."""
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return y, -x
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def reverse(x, y):
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"""Returns a vector pointing in the opposite direction."""
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return -x, -y
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def scale(x, y, factor):
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"""Scale a vector by a given factor."""
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return x * factor, y * factor
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def add(x1, y1, x2, y2):
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"""Add two vectors."""
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return x1 + x2, y1 + y2
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def sub(x1, y1, x2, y2):
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"""Subtract a vector from another."""
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return x1 - x2, y1 - y2
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def vmin(x1, y1, x2, y2):
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"""Return the minimum [x, y] components of the given vectors."""
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return min(x1, x2), min(y1, y2)
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def vmax(x1, y1, x2, y2):
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"""Return the maximum [x, y] components of the given vectors."""
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return max(x1, x2), max(y1, y2)
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def is_equal(x1, y1, x2, y2):
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"""Returns true if two unit vectors are pointed in either the same or
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opposite directions.
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"""
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return math.isclose(abs(dot(x1, y1, x2, y2)), 1, rel_tol=1e-05)
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