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38 lines
1.3 KiB
Python
38 lines
1.3 KiB
Python
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import numpy as np
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from utils.bezier import interpolate
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from utils.space_ops import rotation_matrix
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def straight_path(start_points, end_points, alpha):
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"""
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Same function as interpolate, but renamed to reflect
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intent of being used to determine how a set of points move
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to another set. For instance, it should be a specific case
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of path_along_arc
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"""
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return interpolate(start_points, end_points, alpha)
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def path_along_arc(arc_angle, axis = OUT):
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"""
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If vect is vector from start to end, [vect[:,1], -vect[:,0]] is
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perpendicular to vect in the left direction.
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"""
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if abs(arc_angle) < STRAIGHT_PATH_THRESHOLD:
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return straight_path
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if np.linalg.norm(axis) == 0:
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axis = OUT
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unit_axis = axis/np.linalg.norm(axis)
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def path(start_points, end_points, alpha):
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vects = end_points - start_points
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centers = start_points + 0.5*vects
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if arc_angle != np.pi:
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centers += np.cross(unit_axis, vects/2.0)/np.tan(arc_angle/2)
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rot_matrix = rotation_matrix(alpha*arc_angle, unit_axis)
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return centers + np.dot(start_points-centers, rot_matrix.T)
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return path
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def clockwise_path():
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return path_along_arc(-np.pi)
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def counterclockwise_path():
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return path_along_arc(np.pi)
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