ball = {}
ball.x = 20
ball.y = 80
ball.initial_sprite = 0
ball.sprite = ball.initial_sprite 
ball.frames = 10
ball.is_jumping = false
ball.jumping_frame = 0
ball.jumping_max_frames = 4

function update_ball_sprite()
    ball.sprite += 1
    ball.sprite %= ball.frames
end

function ball_jump(speed)
    if ball.jumping_frame < ball.jumping_max_frames then

        if ball.jumping_frame < ball.jumping_max_frames/2 then
            ball.y -= speed
        else
            ball.y += speed
        end

        ball.jumping_frame+=1
    else
        ball.jumping_frame = 0
        ball.is_jumping = false
    end
end

function _init()
    ticker = 0
end

function _update()
    ticker += 1

    if (btn(2) and not ball.is_jumping) ball.is_jumping = true

    if ((ticker % 2 == 0) and ball.is_jumping) ball_jump(6)

    if (ticker % 3 == 0) update_ball_sprite()

    if (ticker % 30 == 0) ticker = 0
end

function _draw()
    clear_screen(0)
    spr(ball.sprite, ball.x, ball.y)
end

function clear_screen(color)
    rectfill(0,0,127,127,color)
end