-- pico8
-- Riki Klein
-- Bouncing Ball
-- 18.10.17
-- v1


cls()


-- gets called once on startup
function _init()
    count = 0

    ball = {
        x = 64, -- x position
        y = 64, -- y position
        r = 4,  -- radius
        c = 10, -- color
        vx = 0, -- x velocity
        vy = 0  -- y velocity
    }

    ball.vx = rnd(10) - 9
    ball.vy = rnd(10) - 9

    box = {
        x = 0,  -- x position
        y = 0,  -- y position
        w = 10, -- width
        h = 10, -- height
        c = 5   -- color
    }
end


-- gets called 30 times a second
function _update()
    count = count+1


    -- ball movement
    ball.x += ball.vx  -- short for ball.x = ball.x +1
    ball.y += ball.vy


 -- wrap ball
--  if (ball.x - ball.r > 127) then
--      ball.x = -ball.r
--  end

    -- reflect ball
    if (ball.y - ball.r < 0) then
        ball.vy *= -1
    end

 if (ball.x - ball.r < 0) then
        ball.vx *= -1
    end

    if (ball.y + ball.r > 128) then
        ball.vy *= -1
    end

    if (ball.x + ball.r > 128) then
        ball.vx *= -1
    end

end

.y,
        ball.r,
        ball.c
-- gets called 30 times a second
-- (after the _update function)
function _draw()
    cls()

    print("frame: "..count, 0, 0)

    -- draw the ball
    circfill(
        ball.x,
        ball
    )
end