feat(timer): add variable interpolation support via tween.lua

CREDITS.md

@@ -17,3 +17,5 @@
 - [Tsort](https://github.com/bungle/lua-resty-tsort), under BSD-2 Clause
 
 - [Simple Tiled Implementation](https://github.com/karai17/Simple-Tiled-Implementation), under MIT Licence
+
+- [tween.lua](https://github.com/kikito/tween.lua), under MIT Licence

gamecore/modules/timers/init.lua

@@ -25,6 +25,7 @@ local cwd = (...):gsub('%.init$', '') .. "."
 
 local TimersManager = Object:extend()
 local Timer = require(cwd .. "libs.timer")
+local Tween = require(cwd .. "libs.tween")
 
 
 function TimersManager:new(subject)
@@ -33,6 +34,7 @@ function TimersManager:new(subject)
 
   self.timers   = {}
   self.switches = {}
+  self.tweens   = {}
 end
 
 -- UPDATE
@@ -46,7 +48,7 @@ function TimersManager:update(dt)
   end
 
   self:updateSwitches(dt)
-
+  self:updateTweens(dt)
 end
 
 -- TIMER FUNCTIONS
@@ -95,4 +97,35 @@ function TimersManager:updateSwitches(dt)
   end
 end
 
+-- TWEENING FUNCTIONS
+-- Handle tween support via tween.lua
+
+function TimersManager:newTween(start, duration, target, easing)
+  local newTween = {}
+  -- we add the data into a tween wrapper
+  newTween.tween = Tween.new(duration, self.subject, target, easing)
+  newTween.start = self.time + start -- /!\ START IS RELATIVE TO CURRENT TIME
+  newTween.clear = newTween.start + duration
+
+  table.insert(self.tweens, newTween)
+end
+
+function TimersManager:updateTweens(dt)
+  for i, tweenWrapper in ipairs(self.tweens) do
+    if (self.time > tweenWrapper.start) then
+      tweenWrapper.tween:update(dt)
+    end
+  end
+
+  self:clearEndedTweens()
+end
+
+function TimersManager:clearEndedTweens()
+  for i, tweenWrapper in ipairs(self.tweens) do
+    if (self.time > tweenWrapper.clear) then
+      table.remove(self.tweens, i)
+    end
+  end
+end
+
 return TimersManager

gamecore/modules/timers/libs/tween.lua

@@ -0,0 +1,367 @@
+local tween = {
+  _VERSION     = 'tween 2.1.1',
+  _DESCRIPTION = 'tweening for lua',
+  _URL         = 'https://github.com/kikito/tween.lua',
+  _LICENSE     = [[
+    MIT LICENSE
+
+    Copyright (c) 2014 Enrique García Cota, Yuichi Tateno, Emmanuel Oga
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the
+    "Software"), to deal in the Software without restriction, including
+    without limitation the rights to use, copy, modify, merge, publish,
+    distribute, sublicense, and/or sell copies of the Software, and to
+    permit persons to whom the Software is furnished to do so, subject to
+    the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+  ]]
+}
+
+-- easing
+
+-- Adapted from https://github.com/EmmanuelOga/easing. See LICENSE.txt for credits.
+-- For all easing functions:
+-- t = time == how much time has to pass for the tweening to complete
+-- b = begin == starting property value
+-- c = change == ending - beginning
+-- d = duration == running time. How much time has passed *right now*
+
+local pow, sin, cos, pi, sqrt, abs, asin = math.pow, math.sin, math.cos, math.pi, math.sqrt, math.abs, math.asin
+
+-- linear
+local function linear(t, b, c, d) return c * t / d + b end
+
+-- quad
+local function inQuad(t, b, c, d) return c * pow(t / d, 2) + b end
+local function outQuad(t, b, c, d)
+  t = t / d
+  return -c * t * (t - 2) + b
+end
+local function inOutQuad(t, b, c, d)
+  t = t / d * 2
+  if t < 1 then return c / 2 * pow(t, 2) + b end
+  return -c / 2 * ((t - 1) * (t - 3) - 1) + b
+end
+local function outInQuad(t, b, c, d)
+  if t < d / 2 then return outQuad(t * 2, b, c / 2, d) end
+  return inQuad((t * 2) - d, b + c / 2, c / 2, d)
+end
+
+-- cubic
+local function inCubic (t, b, c, d) return c * pow(t / d, 3) + b end
+local function outCubic(t, b, c, d) return c * (pow(t / d - 1, 3) + 1) + b end
+local function inOutCubic(t, b, c, d)
+  t = t / d * 2
+  if t < 1 then return c / 2 * t * t * t + b end
+  t = t - 2
+  return c / 2 * (t * t * t + 2) + b
+end
+local function outInCubic(t, b, c, d)
+  if t < d / 2 then return outCubic(t * 2, b, c / 2, d) end
+  return inCubic((t * 2) - d, b + c / 2, c / 2, d)
+end
+
+-- quart
+local function inQuart(t, b, c, d) return c * pow(t / d, 4) + b end
+local function outQuart(t, b, c, d) return -c * (pow(t / d - 1, 4) - 1) + b end
+local function inOutQuart(t, b, c, d)
+  t = t / d * 2
+  if t < 1 then return c / 2 * pow(t, 4) + b end
+  return -c / 2 * (pow(t - 2, 4) - 2) + b
+end
+local function outInQuart(t, b, c, d)
+  if t < d / 2 then return outQuart(t * 2, b, c / 2, d) end
+  return inQuart((t * 2) - d, b + c / 2, c / 2, d)
+end
+
+-- quint
+local function inQuint(t, b, c, d) return c * pow(t / d, 5) + b end
+local function outQuint(t, b, c, d) return c * (pow(t / d - 1, 5) + 1) + b end
+local function inOutQuint(t, b, c, d)
+  t = t / d * 2
+  if t < 1 then return c / 2 * pow(t, 5) + b end
+  return c / 2 * (pow(t - 2, 5) + 2) + b
+end
+local function outInQuint(t, b, c, d)
+  if t < d / 2 then return outQuint(t * 2, b, c / 2, d) end
+  return inQuint((t * 2) - d, b + c / 2, c / 2, d)
+end
+
+-- sine
+local function inSine(t, b, c, d) return -c * cos(t / d * (pi / 2)) + c + b end
+local function outSine(t, b, c, d) return c * sin(t / d * (pi / 2)) + b end
+local function inOutSine(t, b, c, d) return -c / 2 * (cos(pi * t / d) - 1) + b end
+local function outInSine(t, b, c, d)
+  if t < d / 2 then return outSine(t * 2, b, c / 2, d) end
+  return inSine((t * 2) -d, b + c / 2, c / 2, d)
+end
+
+-- expo
+local function inExpo(t, b, c, d)
+  if t == 0 then return b end
+  return c * pow(2, 10 * (t / d - 1)) + b - c * 0.001
+end
+local function outExpo(t, b, c, d)
+  if t == d then return b + c end
+  return c * 1.001 * (-pow(2, -10 * t / d) + 1) + b
+end
+local function inOutExpo(t, b, c, d)
+  if t == 0 then return b end
+  if t == d then return b + c end
+  t = t / d * 2
+  if t < 1 then return c / 2 * pow(2, 10 * (t - 1)) + b - c * 0.0005 end
+  return c / 2 * 1.0005 * (-pow(2, -10 * (t - 1)) + 2) + b
+end
+local function outInExpo(t, b, c, d)
+  if t < d / 2 then return outExpo(t * 2, b, c / 2, d) end
+  return inExpo((t * 2) - d, b + c / 2, c / 2, d)
+end
+
+-- circ
+local function inCirc(t, b, c, d) return(-c * (sqrt(1 - pow(t / d, 2)) - 1) + b) end
+local function outCirc(t, b, c, d)  return(c * sqrt(1 - pow(t / d - 1, 2)) + b) end
+local function inOutCirc(t, b, c, d)
+  t = t / d * 2
+  if t < 1 then return -c / 2 * (sqrt(1 - t * t) - 1) + b end
+  t = t - 2
+  return c / 2 * (sqrt(1 - t * t) + 1) + b
+end
+local function outInCirc(t, b, c, d)
+  if t < d / 2 then return outCirc(t * 2, b, c / 2, d) end
+  return inCirc((t * 2) - d, b + c / 2, c / 2, d)
+end
+
+-- elastic
+local function calculatePAS(p,a,c,d)
+  p, a = p or d * 0.3, a or 0
+  if a < abs(c) then return p, c, p / 4 end -- p, a, s
+  return p, a, p / (2 * pi) * asin(c/a) -- p,a,s
+end
+local function inElastic(t, b, c, d, a, p)
+  local s
+  if t == 0 then return b end
+  t = t / d
+  if t == 1  then return b + c end
+  p,a,s = calculatePAS(p,a,c,d)
+  t = t - 1
+  return -(a * pow(2, 10 * t) * sin((t * d - s) * (2 * pi) / p)) + b
+end
+local function outElastic(t, b, c, d, a, p)
+  local s
+  if t == 0 then return b end
+  t = t / d
+  if t == 1 then return b + c end
+  p,a,s = calculatePAS(p,a,c,d)
+  return a * pow(2, -10 * t) * sin((t * d - s) * (2 * pi) / p) + c + b
+end
+local function inOutElastic(t, b, c, d, a, p)
+  local s
+  if t == 0 then return b end
+  t = t / d * 2
+  if t == 2 then return b + c end
+  p,a,s = calculatePAS(p,a,c,d)
+  t = t - 1
+  if t < 0 then return -0.5 * (a * pow(2, 10 * t) * sin((t * d - s) * (2 * pi) / p)) + b end
+  return a * pow(2, -10 * t) * sin((t * d - s) * (2 * pi) / p ) * 0.5 + c + b
+end
+local function outInElastic(t, b, c, d, a, p)
+  if t < d / 2 then return outElastic(t * 2, b, c / 2, d, a, p) end
+  return inElastic((t * 2) - d, b + c / 2, c / 2, d, a, p)
+end
+
+-- back
+local function inBack(t, b, c, d, s)
+  s = s or 1.70158
+  t = t / d
+  return c * t * t * ((s + 1) * t - s) + b
+end
+local function outBack(t, b, c, d, s)
+  s = s or 1.70158
+  t = t / d - 1
+  return c * (t * t * ((s + 1) * t + s) + 1) + b
+end
+local function inOutBack(t, b, c, d, s)
+  s = (s or 1.70158) * 1.525
+  t = t / d * 2
+  if t < 1 then return c / 2 * (t * t * ((s + 1) * t - s)) + b end
+  t = t - 2
+  return c / 2 * (t * t * ((s + 1) * t + s) + 2) + b
+end
+local function outInBack(t, b, c, d, s)
+  if t < d / 2 then return outBack(t * 2, b, c / 2, d, s) end
+  return inBack((t * 2) - d, b + c / 2, c / 2, d, s)
+end
+
+-- bounce
+local function outBounce(t, b, c, d)
+  t = t / d
+  if t < 1 / 2.75 then return c * (7.5625 * t * t) + b end
+  if t < 2 / 2.75 then
+    t = t - (1.5 / 2.75)
+    return c * (7.5625 * t * t + 0.75) + b
+  elseif t < 2.5 / 2.75 then
+    t = t - (2.25 / 2.75)
+    return c * (7.5625 * t * t + 0.9375) + b
+  end
+  t = t - (2.625 / 2.75)
+  return c * (7.5625 * t * t + 0.984375) + b
+end
+local function inBounce(t, b, c, d) return c - outBounce(d - t, 0, c, d) + b end
+local function inOutBounce(t, b, c, d)
+  if t < d / 2 then return inBounce(t * 2, 0, c, d) * 0.5 + b end
+  return outBounce(t * 2 - d, 0, c, d) * 0.5 + c * .5 + b
+end
+local function outInBounce(t, b, c, d)
+  if t < d / 2 then return outBounce(t * 2, b, c / 2, d) end
+  return inBounce((t * 2) - d, b + c / 2, c / 2, d)
+end
+
+tween.easing = {
+  linear    = linear,
+  inQuad    = inQuad,    outQuad    = outQuad,    inOutQuad    = inOutQuad,    outInQuad    = outInQuad,
+  inCubic   = inCubic,   outCubic   = outCubic,   inOutCubic   = inOutCubic,   outInCubic   = outInCubic,
+  inQuart   = inQuart,   outQuart   = outQuart,   inOutQuart   = inOutQuart,   outInQuart   = outInQuart,
+  inQuint   = inQuint,   outQuint   = outQuint,   inOutQuint   = inOutQuint,   outInQuint   = outInQuint,
+  inSine    = inSine,    outSine    = outSine,    inOutSine    = inOutSine,    outInSine    = outInSine,
+  inExpo    = inExpo,    outExpo    = outExpo,    inOutExpo    = inOutExpo,    outInExpo    = outInExpo,
+  inCirc    = inCirc,    outCirc    = outCirc,    inOutCirc    = inOutCirc,    outInCirc    = outInCirc,
+  inElastic = inElastic, outElastic = outElastic, inOutElastic = inOutElastic, outInElastic = outInElastic,
+  inBack    = inBack,    outBack    = outBack,    inOutBack    = inOutBack,    outInBack    = outInBack,
+  inBounce  = inBounce,  outBounce  = outBounce,  inOutBounce  = inOutBounce,  outInBounce  = outInBounce
+}
+
+
+
+-- private stuff
+
+local function copyTables(destination, keysTable, valuesTable)
+  valuesTable = valuesTable or keysTable
+  local mt = getmetatable(keysTable)
+  if mt and getmetatable(destination) == nil then
+    setmetatable(destination, mt)
+  end
+  for k,v in pairs(keysTable) do
+    if type(v) == 'table' then
+      destination[k] = copyTables({}, v, valuesTable[k])
+    else
+      destination[k] = valuesTable[k]
+    end
+  end
+  return destination
+end
+
+local function checkSubjectAndTargetRecursively(subject, target, path)
+  path = path or {}
+  local targetType, newPath
+  for k,targetValue in pairs(target) do
+    targetType, newPath = type(targetValue), copyTables({}, path)
+    table.insert(newPath, tostring(k))
+    if targetType == 'number' then
+      assert(type(subject[k]) == 'number', "Parameter '" .. table.concat(newPath,'/') .. "' is missing from subject or isn't a number")
+    elseif targetType == 'table' then
+      checkSubjectAndTargetRecursively(subject[k], targetValue, newPath)
+    else
+      assert(targetType == 'number', "Parameter '" .. table.concat(newPath,'/') .. "' must be a number or table of numbers")
+    end
+  end
+end
+
+local function checkNewParams(duration, subject, target, easing)
+  assert(type(duration) == 'number' and duration > 0, "duration must be a positive number. Was " .. tostring(duration))
+  local tsubject = type(subject)
+  assert(tsubject == 'table' or tsubject == 'userdata', "subject must be a table or userdata. Was " .. tostring(subject))
+  assert(type(target)== 'table', "target must be a table. Was " .. tostring(target))
+  assert(type(easing)=='function', "easing must be a function. Was " .. tostring(easing))
+  checkSubjectAndTargetRecursively(subject, target)
+end
+
+local function getEasingFunction(easing)
+  easing = easing or "linear"
+  if type(easing) == 'string' then
+    local name = easing
+    easing = tween.easing[name]
+    if type(easing) ~= 'function' then
+      error("The easing function name '" .. name .. "' is invalid")
+    end
+  end
+  return easing
+end
+
+local function performEasingOnSubject(subject, target, initial, clock, duration, easing)
+  local t,b,c,d
+  for k,v in pairs(target) do
+    if type(v) == 'table' then
+      performEasingOnSubject(subject[k], v, initial[k], clock, duration, easing)
+    else
+      t,b,c,d = clock, initial[k], v - initial[k], duration
+      subject[k] = easing(t,b,c,d)
+    end
+  end
+end
+
+-- Tween methods
+
+local Tween = {}
+local Tween_mt = {__index = Tween}
+
+function Tween:set(clock)
+  assert(type(clock) == 'number', "clock must be a positive number or 0")
+
+  self.initial = self.initial or copyTables({}, self.target, self.subject)
+  self.clock = clock
+
+  if self.clock <= 0 then
+
+    self.clock = 0
+    copyTables(self.subject, self.initial)
+
+  elseif self.clock >= self.duration then -- the tween has expired
+
+    self.clock = self.duration
+    copyTables(self.subject, self.target)
+
+  else
+
+    performEasingOnSubject(self.subject, self.target, self.initial, self.clock, self.duration, self.easing)
+
+  end
+
+  return self.clock >= self.duration
+end
+
+function Tween:reset()
+  return self:set(0)
+end
+
+function Tween:update(dt)
+  assert(type(dt) == 'number', "dt must be a number")
+  return self:set(self.clock + dt)
+end
+
+
+-- Public interface
+
+function tween.new(duration, subject, target, easing)
+  easing = getEasingFunction(easing)
+  checkNewParams(duration, subject, target, easing)
+  return setmetatable({
+    duration  = duration,
+    subject   = subject,
+    target    = target,
+    easing    = easing,
+    clock     = 0
+  }, Tween_mt)
+end
+
+return tween