打砖块：弹球不落地就有戏

fx-breakout

local Breakout = {}
local KEY = { R = 7 }

function Breakout.Step(ball, dt)
    ball.x = ball.x + ball.vx * dt
    ball.y = ball.y + ball.vy * dt
    -- 三面墙反弹
    if ball.x < KEY.R then ball.x = KEY.R; ball.vx = math.abs(ball.vx) end
    if ball.x > SL:GetValue("width") - KEY.R then
        ball.x = SL:GetValue("width") - KEY.R
        ball.vx = -math.abs(ball.vx)
    end
    if ball.y < KEY.R then ball.y = KEY.R; ball.vy = math.abs(ball.vy) end
    -- 托板: 接触点搓出横向分量
    if ball.vy > 0 and SL:GetValue("ballOnPad", ball) then
        ball.vy = -math.abs(ball.vy)
        local off = ball.x - SL:GetValue("padX")
        ball.vx = ball.vx + off * 3
        -- 限速保向: 球速恒定是手感生命线
        local sp = math.sqrt(ball.vx * ball.vx + ball.vy * ball.vy)
        local target = SL:GetValue("ballSpeed")
        ball.vx = ball.vx / sp * target
        ball.vy = ball.vy / sp * target
        SL:PlaySfx("pad_hit")
    end
    -- 砖块碰撞: 分轴判定反弹方向
    local brick = SL:GetValue("hitBrick", ball)
    if brick then
        if SL:GetValue("hitAxis") == "x" then
            ball.vx = -ball.vx
        else
            ball.vy = -ball.vy
        end
        SL:BreakBrick(brick)
    end
    -- 落底: 重置
    if ball.y > SL:GetValue("height") + 16 then
        SL:SendEvent("ball_lost")
    end
end

return Breakout