def update(self):
self.force[1] += -.1 * self.mass
self.compute_wall_force_circle(self.size, .5)
# air resistance
if util.vmag(self.vel) > 1:
vmag = util.vmag(self.vel)
vdir = util.vdivs(self.vel, -.9 * vmag)
self.force = util.vadd(self.force, vdir)
self.integrate_force()
self.vel[0] = util.clamp(self.vel[0], -20, 20)
self.vel[1] = util.clamp(self.vel[1], -20, 20)
def draw(self):
orth = [self.vel[1], -self.vel[0]]
orth = util.vmuls(orth, self.size / util.vmag(orth))
return group(colors.red,
shapes.regular_polygon(self.pos[0], self.pos[1],
30, self.size),
quads(color(1, 0, 0, .5),
self.pos[0] + orth[0], self.pos[1] + orth[1],
self.pos[0] - orth[0], self.pos[1] - orth[1],
color(1, 0, 0, 0),
self.pos[0] - 10*self.vel[0] - orth[0],
self.pos[1] - 10*self.vel[1] - orth[1],
self.pos[0] - 10*self.vel[0] + orth[0],
self.pos[1] - 10*self.vel[1] + orth[1]
))