斗转星移：刀到脸上人换了位

fx-swap

local Swap = {}
local KEY = { DIST = 100, DASH_SPD = 300 }
local busy = false

local function PosOf(vid)
    return SL:GetValue("actorX", vid), SL:GetValue("actorY", vid)
end

local function FaceTo(vid, tx, ty)
    local x, y = PosOf(vid)
    -- 幂尔框架按坐标差换算朝向
    SL:SetActorDir(vid, SL:CalcDir(tx - x, ty - y))
end

function Swap.Try(self_, target)
    if busy then return false end
    local sx, sy = PosOf(self_)
    local tx, ty = PosOf(target)
    local dx, dy = tx - sx, ty - sy
    if dx * dx + dy * dy > KEY.DIST * KEY.DIST then
        return false      -- 不在窗口距离内，换不得
    end
    busy = true
    -- 双方同时淡出
    SL:SetActorAlpha(self_, 60)
    SL:SetActorAlpha(target, 60)
    -- 一帧内对调坐标
    SL:SetActorPos(self_, tx, ty)
    SL:SetActorPos(target, sx, sy)
    SL:ShowSystemTips("斗转星移!")
    -- 0.4 秒后恢复透明度并各自转向
    SL:ScheduleOnce(function()
        SL:SetActorAlpha(self_, 255)
        SL:SetActorAlpha(target, 255)
        local nx, ny = PosOf(target)
        FaceTo(target, sx, sy)     -- 狼怪转身找人
        FaceTo(self_, nx, ny)
        busy = false
    end, 0.4)
    return true
end

-- 狼怪冲锋过头的表现：保持原方向再滑行一小段
function Swap.OnMonsterDash(target)
    SL:SetActorVelocity(target, -KEY.DASH_SPD, 0)
    SL:ScheduleOnce(function()
        SL:SetActorVelocity(target, 0, 0)
    end, 0.3)
end

return Swap