def plotArrow(self, time, factorLength = 40, factorWidth = 10, angleArrows = math.pi/4, color = (0, 255, 0)): startPos = self.currentPosition(time) endPos = startPos + self.velocity*factorLength width = numpy.linalg.norm(self.velocity)*factorWidth arrowUp = Numerical.pointAtAngle(endPos, math.pi + self.angle - angleArrows, width) arrowDown = Numerical.pointAtAngle(endPos, math.pi + self.angle + angleArrows, width) py.draw.aaline(self.surfaceToBlit, color, startPos, endPos) py.draw.aaline(self.surfaceToBlit, color, endPos, arrowUp) py.draw.aaline(self.surfaceToBlit, color, endPos, arrowDown)