Make the AnimationNode handle its own state

lib/animation_node.lua

@@ -1,3 +1,5 @@
+local easing = require "lib.utils.easing"
+
 --- @alias voidCallback fun(): nil
 --- @alias animationRunner fun(node: AnimationNode)
 
@@ -28,6 +30,9 @@
 --- @field children AnimationNode[]
 --- @field finish voidCallback
 --- @field onEnd voidCallback?
+--- @field duration number продолжительность в миллисекундах
+--- @field easing ease функция смягчения
+--- @field t number прогресс анимации
 local animation = {}
 animation.__index = animation
 
@@ -50,7 +55,21 @@ function animation:chain(children)
     return self
 end
 
---- @param data {[1]: animationRunner?, onEnd?: voidCallback, children?: AnimationNode[]}
+--- Возвращает текущий прогресс анимации с учетом смягчения
+function animation:getValue()
+    return self.easing(self.t)
+end
+
+function animation:update(dt)
+    if self.t < 1 then
+        self.t = self.t + dt * 1000 / self.duration -- в знаменателе продолжительность анимации в секундах
+    else
+        self.t = 1
+        self:finish()
+    end
+end
+
+--- @param data {[1]: animationRunner?, onEnd?: voidCallback, duration: number?, easing: ease?, children?: AnimationNode[]}
 --- @return AnimationNode
 local function new(data)
     local t = setmetatable({}, animation)
@@ -61,6 +80,9 @@ local function new(data)
     t.count = 1 -- своя анимация
     t.children = {}
     t:chain(data.children or {})
+    t.duration = data.duration or 1000
+    t.easing = data.easing or easing.linear
+    t.t = 0
     t.finish = function()
         t:bubbleUp()
         for _, anim in ipairs(t.children) do