VPython:在动画开始之前，是否可以显示画布?

我一直在开发一款类似于《愤怒的小鸟》的游戏，在这款游戏中，玩家将一枚炮弹射向目标，目的是将其摧毁。然而，我正在努力寻找一种方式来显示画布之前，初始启动参数输入和动画开始。当代码运行时发生的第一件事是它要求输入，但我想在这之前显示可视化。想知道是否有一种简单的方法可以做到这一点，代码如下。

scene = canvas(width=640, height=480, center=vector(8,5,0),range=8, background=color.blue)
ground = box(pos=vector(8,-5,0), length=16, height=10, width=0.5, color=color.green)

dist = 5 + random()*10 
target = box(pos=vector(dist,1,0), length=0.5, height=2, width=0.5, color=color.red)

height = random() #determines random height of platform between 0 and 1 meters
platform = box(pos=vector(-2,height-0.25,0), length=4, height=0.5, width=0.5, color=color.white)

bird = sphere(pos=vector(0,height+0.3,0), radius=0.3, color=color.yellow)

hit = 0

while hit == 0: #loops until player hits target

    #Take initial parameters from player
    v0 = float(input('Input your launch velocity:'))
    dtheta = float(input('Input your launch angle in degrees:'))
    theta = np.radians(dtheta) #convert launch angle to radians

    #Draw arrow for initial momentum
    px = 0.1*v0*np.cos(theta) #calculate initial x momentum
    py = 0.1*v0*np.sin(theta) #calculate initial y momentum
    momentum = arrow(pos=bird.pos, axis=vector(px,py,0), shaftwidth=0.1, color=color.orange) #draw arrow representing projectiles initial momentum

    # Calculate position of the projectile at a specified interval of time
    # Code adapted from my submission to PHAS0007: Computing Session 8

    #Define intial parameters
    g = 9.81
    x = x0 = 0
    y = y0 = height 
    dt = 0.0001 #timestep
    t = 0

    #conditions that alllow looping when projectile is not in contact with target
    while (y > 0 and (x < dist-0.25 or x > dist+0.25)) or (y > 2 and x >= dist-0.25 and x<= dist+0.25):

            rate(5000) #set rate of animation

            x = x0 + v0*t*np.cos(theta) # calculate new x position
            y = y0 + v0*t*np.sin(theta)-0.5*g*t**2 # calculate new y position
            bird.pos = vector(x,y,0) # redraw projectile at new position

            px = 0.1*v0*np.cos(theta) #calculate x momentum
            py = 0.1*v0*np.sin(theta)-0.1*g*t #calculate y momentum
            momentum.pos = bird.pos #redraw momentum arrow in new position
            momentum.axis = vector(px,py,0) #redraw momentum arrow direction

            t += dt # increase timestep increment by dt

    momentum.visible = False #removes momentum arrow after projectile motion is finished

    #use inverse condition of the loop to determine and print whether the target was hit or not
    if y >= 0 and y <= 2 and x >= dist-0.25 and x <= dist+0.25:

        #calculate whether the target topples or not
        trest = 0.5*100*g*0.5 #calculate the restoring torque
        contact_t = 0.01 #define the time projectile is in contact with target
        fapp = vector(px, py, 0) / contact_t #calculate applied force of projectile on target
        tapp = cross(fapp, vector((dist+0.25)-x, -y, 0)) #calculate applied torque vector of projectile on target
        tappm = mag(tapp) #calculate magnitude of applied torque vector

        if tappm > trest: #target toppled

            #redraw target to be toppled
            target.pos = vector(dist+1.25,0.25,0)
            target.length = 2
            target.height =0.5
            print('Target toppled, success!')
            hit = 1

        else: #target hit but not toppled
            print('Target hit but not toppled, try again.')

        #animate bird dropping to ground
        t=0 #reset time counter
        y0=y #set y0 equal to current y position
        while y > 0.3:
            rate(5000)
            y = y0 - 0.5*g*t**2            
            bird.pos = vector(x,y,0)
            t += dt

    else:
        print('Target Missed, try again.')

问题来源StackOverflow 地址：/questions/59380361/vpython-is-there-anyway-to-display-a-canvas-before-an-animation-begins