from visual import *

# 改變螢幕長寬比例
scene.height = 2.5 * scene.width

half = 100
floor = box(pos=(0, -half, 0), size=(2*half,1,2*half), color=color.blue)
ball = sphere(pos=(0,1.5* half,0), radius=1, color=color.white,velocity=vector(0,0,0))


dt = 0.3
g = -9.8

# floor.visible = False

# 增加了trail來記錄所走過的痕跡
trail = points()
while 1:
    rate(100)
    trail.append(ball.pos)
#    trail.append(ball.pos, retain=10)
    ball.pos = ball.pos + ball.velocity*dt
    if ball.y < -half + ball.radius:
        break
    ball.velocity.y = ball.velocity.y + g*dt