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view scripts/timeToCollision.py @ 462:af2222c0c9c0
TTC tested and updatet!
author | Sohail Zangenehpour <sohail.zangenehpour@mail.mcgill.ca> |
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date | Mon, 03 Feb 2014 15:41:57 -0500 |
parents | cb41f9a4652b |
children |
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def timeToCollision(obj1,obj2,collisionDistanceThreshold,frameNum,framePerSecond): import numpy as np x1 = obj1.getPositionAtInstant(frameNum).x y1 = obj1.getPositionAtInstant(frameNum).y x2 = obj2.getPositionAtInstant(frameNum).x y2 = obj2.getPositionAtInstant(frameNum).y v1x = obj1.getVelocityAtInstant(frameNum).x * framePerSecond v1y = obj1.getVelocityAtInstant(frameNum).y * framePerSecond v2x = obj2.getVelocityAtInstant(frameNum).x * framePerSecond v2y = obj2.getVelocityAtInstant(frameNum).y * framePerSecond l = collisionDistanceThreshold a = pow(v1x-v2x,2) + pow(v1y-v2y,2) b = 2 * ((x1-x2) * (v1x-v2x) + (y1-y2) * (v1y-v2y)) c = pow(x1-x2,2) + pow(y1-y2,2) - pow(l,2) if pow(b,2) >= 4*a*c: ttc1 = (-b + np.sqrt(pow(b,2) - 4*a*c)) / (2*a) ttc2 = (-b - np.sqrt(pow(b,2) - 4*a*c)) / (2*a) if ttc1 >= 0 and ttc2 >= 0: ttc = min(ttc1,ttc2) else: if ttc1 < 0: ttc = ttc2 if ttc2 < 0: ttc = ttc1 if ttc1 < 0 and ttc2 < 0: ttc = [] else: ttc = [] return ttc