Love2D，LUA Tween 重置

Question

我的补间有问题。按住该按钮时，我正在使用 tween.lua 向左或向右移动我的角色。释放时，播放器返回中间。当角色向左或向右移动时，补间非常有效，但是由于某种原因，当它必须回到中间时，角色只是在那里扭曲而不是补间。我怀疑基础 X 覆盖了它，或者我没有在正确的时刻重置。 这是我的代码：

--Local variables
local lg = love.graphics
local lk = love.keyboard

function player:load(arg) --Player load function. Called when loaded.

    self.img = lg.newImage(currentPimg)
    playerWidth = player.img:getWidth() --Gets player image width and sets as a variable
    self.mid = width/2 - playerWidth/2
    self.left = 100 - playerWidth/2
    self.right = width - 100 - playerWidth/2

    self.x = player.mid
    self.y = height-150
    self.speed = 0.04

    GoMid = tween.new(player.speed , player, {x=player.mid}, 'linear')
    GoLeft = tween.new(player.speed , player, {x=player.left}, 'linear')
    GoRight = tween.new(player.speed , player, {x=player.right}, 'linear')
end

function player:update(dt) --Player update function. Called each frame, passes DT (delta time)

playerWidth = player.img:getWidth() --Gets player image width and sets as a variable

if LeftStarted and not isLeft then
    GoLeft:reset()
    LeftStarted = false
end
if RightStarted and not isRight then
    GoRight:reset()
    RightStarted = false
end
if MidStarted and not isMid then
    GoMid:reset()
    MidStarted = false
end


if isMid then --If is true then do action
    GoMid:update(dt)
    MidStarted = true
end
if isRight then --If is true then do action
    GoRight:update(dt)
    RightStarted = true
end
if isLeft then --If is true then do action
    GoLeft:update(dt)
    LeftStarted = true
end

if lk.isDown("left", "a") and not isRight then --this check needs to be done since the code is executed the first time. If I do not check weird stuff happens
    isLeft = true 
    isRight, isMid = false
elseif lk.isDown("right", "d") then --checks if the button is down and returns true if it is
    isRight = true
    isLeft, isMid = false
else -- if nothing is down resets player to mid and all variables to false
    isLeft, isRight = false
    isMid = true
end
end

function player:draw(dt) --Draw function. Called each frame, passes DT (delta time)

lg.draw(player.img, player.x, player.y) --Draws player image at X and Y
end

Answer 1

代码的工作版本

所以，在把代码弄乱了很多之后，我可以向你展示以下内容：

player = { } --Required table thing

--Local variables
local lg = love.graphics
local lk = love.keyboard

function player:load(arg) --Player load function. Called when loaded.

        self.img = lg.newImage(currentPimg)
        playerWidth = player.img:getWidth() --Gets player image width and sets as a variable
        self.mid = width/2 - playerWidth/2
        self.left = 100 - playerWidth/2
        self.right = width - 100 - playerWidth/2

        self.x = player.mid
        self.y = height-150
        self.speed = 0.5

        GoMid = tween.new(player.speed , player, {x=player.mid}, 'linear')
        GoLeft = tween.new(player.speed , player, {x=player.left}, 'linear')
        GoRight = tween.new(player.speed , player, {x=player.right}, 'linear')
end

function player:update(dt) --Player update function. Called each frame, passes DT (delta time)

    playerWidth = player.img:getWidth() --Gets player image width and sets as a variable

    if LeftStarted and not isLeft then
    GoMid = tween.new(player.speed , player, {x=player.mid}, 'linear')
    LeftNeedsReset = true
        LeftStarted = false
    end
    if RightStarted and not isRight then
    GoMid = tween.new(player.speed , player, {x=player.mid}, 'linear')
    RightNeedsReset = true
        RightStarted = false
    end

    if isMid then --If is true then do action
        GoMid:update(dt)
    end
    if isRight then --If is true then do action
    if RightNeedsReset then
      GoRight:reset()
      RightNeedsReset = false
    end
        GoRight:update(dt)
        RightStarted = true
    end
    if isLeft then --If is true then do action
    if LeftNeedsReset then
      GoLeft:reset()
      LeftNeedsReset = false
    end
        GoLeft:update(dt)
        LeftStarted = true
    end

    if lk.isDown("left", "a") and not isRight then --this check needs to be done since the code is executed the first time. If I do not check weird stuff happens
        isLeft = true
        isRight, isMid = false, false
    elseif lk.isDown("right", "d") then --checks if the button is down and returns true if it is
        isRight = true
        isLeft, isMid = false, false
    else -- if nothing is down resets player to mid and all variables to false
        isLeft, isRight = false, false
        isMid = true
    end
end

function player:draw(dt) --Draw function. Called each frame, passes DT (delta time)

    lg.draw(player.img, player.x, player.y) --Draws player image at X and Y
end

这种实现我认为你想要的（玩家平稳地回到中心），但我仍然认为这不是一个好的解决方案。
我所做的是，每当玩家需要开始向中心移动时，我都会使用适当的起点进行新的动作，并且我会延迟方向动作的重置，直到有必要为止，因为它会使玩家跳回起点。

观察

我在使用您的代码时注意到了一些事情。

第一个是您尝试为多个变量赋值。据我所知，它在 Lua 中不起作用。为此，您必须这样写：
isLeft, isRight = false, false
而不是这个：
isLeft, isRight = false

我在调试时花了一段时间才注意到的一件事是，您编写的方向的重置部分与更新部分的顺序不同。除非你有充分的理由这样做，否则我不会认为这是一个好习惯。

建议

在我看来，这个库并不适合这项任务（虽然我不是很了解，但这是我在调试代码时第一次使用它）。这可以通过语言和框架本身的内置功能轻松完成。你可以有一个变量来跟踪当前位置，然后不断地朝着按下按钮的方向改变它直到一个限制，然后当所有的键都被释放时将它拖回中心。

这段代码我没有测试过，只是瞎写，但可能看起来是这样的：

if love.keyboard.isDown("left") then
  if currentPosition > middlePosition - movementLimit then
    currentPosition = currentPosition - 20 * dt
  end
elseif love.keyboard.isDown("right") then
  if currentPosition < middlePosition + movementLimit then
    currentPosition = currentPosition + 20 * dt
  end
else
  if currentPosition < middlePosition then
    currentPosition = currentPosition + 20 * dt
  elseif currentPosition > middlePosition then
    currentPosition = currentPosition - 20 * dt
  end
end

---

ps.：我不介意的另一件事是，如果您可以将源代码中 cmets 的措辞保持在良好品味的范围内。 [khm..debugging.lua : line 7.khm..]

希望您的项目取得成功！祝你好运！