Animator example

--# Animator
-- Animation class
--
-- Create with Animator(start, stop, time, easing, callback)
-- "start" is the start value
-- "end" is the end value
-- "time" is the time taken, in seconds, to complete the animation
-- "easing" is the easing of the animation (how it slows down/speeds up)
-- use EASENONE, EASEIN, EASEOUT, or EASEBOTH
-- "callback" is the function that is called once the animation is 
-- complete
--
-- Get the current value of the animation with
-- Animator:value()
-- This will call the callback function if the function is complete
-- (it only calls it once)
-- 
-- You can also get the value at any time t between 0 and 1 using
-- Animator:valueAt(t, [easing])

EASENONE = 1
EASEIN = 2
EASEOUT = 3
EASEBOTH = 4

Animator = class()

function Animator:init(start, stop, time, easing, callback)
    self.start = start
    self.stop = stop
    self.stopTime = time
    self.startTime = ElapsedTime
    self.easing = easing or EASENONE
    self.complete = false
    self.callback = callback or function() end
end

function Animator:valueAt(t, easing)
    easing = easing or self.easing
    if self.easing == EASENONE then
        value = t * (self.stop - self.start) + self.start
    elseif self.easing == EASEOUT then
        value = math.sin(math.pi/2 * t)*
                (self.stop-self.start)+self.start
    elseif self.easing == EASEIN then
        value = (-math.cos(math.pi/2 * t)+1)*
                (self.stop-self.start)+self.start
    elseif self.easing == EASEBOTH then
        value = (-math.cos(math.pi * t)+1)/2*
                (self.stop-self.start)+self.start
    end
    return value
end

function Animator:value()
    time = (ElapsedTime - self.startTime)/self.stopTime
    time = math.min(time, 1)
    if time == 1 then
        if not self.complete then
            self.complete = true
            self.callback()
        end
        return self.stop
    else
        return self:valueAt(time)
    end
end
--# Main
-- Animation

-- Use this function to perform your initial setup
function setup()
    tests = {Test1(), Test2()}
    iparameter("testNumber", 1, #tests)
    currentTest = tests[1]
    currentTestNum = 1
end

-- This function gets called once every frame
function draw()
    if currentTestNum ~= testNumber then
        currentTestNum = testNumber
        currentTest = tests[currentTestNum]
        currentTest:reset()
    end
    currentTest:draw()
end
--# Test1
Test1 = class()

function Test1:init()
    -- you can accept and set parameters here
    self:reset()
end

function Test1:reset()
    self.firstflipdone = function()
        self.anim2 = Animator(-90, 0, 0.5, EASEOUT, self.secondflipdone)
        self.flipstate = 1
    end
    
    self.secondflipdone = function()
        self.flipstate = 2
    end
    
    self.anim1 = Animator(0, 90, 0.5, EASEIN, self.firstflipdone)
    self.flipstate = 0
end

function Test1:draw()
    -- Codea does not automatically call this method
    -- This sets a dark background color
    background(0, 0, 0, 255)

    -- This sets the line thickness
    strokeWidth(5)
    
    -- Do your drawing here
    
    pushMatrix()
    pushStyle()
    rectMode(CENTER)
    if self.flipstate == 0 then
        perspective()
        translate(0, 0, -930)
        
        fill(255, 0, 0, 255)
        rotate(self.anim1:value(), 1, 0, 0)
        rect(0, 0, 200, 200)
        fill(0, 0, 0, 255)
        translate(0, 0, 1)
        text("Red!", 0,0)
    elseif self.flipstate == 1 then
        perspective()
        translate(0, 0, -930)
        
        fill(0, 131, 255, 255)
        rotate(self.anim2:value(), 1, 0, 0)
        rect(0, 0, 200, 200)
        fill(0, 0, 0, 255)
        translate(0, 0, 1)
        text("Blue!", 0,0)
    else
        ortho()
        translate(WIDTH/2, HEIGHT/2)
        
        fill(0, 131, 255, 255)
        rect(0, 0, 200, 200)
        fill(0, 0, 0, 255)
        text("Blue!", 0,0)
    end
    popStyle()
    popMatrix()
end
--# Test2
Test2 = class()

function Test2:init()
    -- you can accept and set parameters here
    self:reset()
end

function Test2:reset()
    self.dokey1 = function() self:key1() end
    self.dokey2 = function() self:key2() end
    self.dokey3 = function() self:key3() end
    
    self.dokey1()
end
function Test2:draw()
    -- Codea does not automatically call this method
    background(0, 0, 0, 255)
    ortho()
    pushMatrix()
    translate(200+self.translateAnim:value(), 200)
    scale(self.scaleAnim:value(), self.scaleAnim:value())
    fill(255, 255, 255, 255)
    rectMode(CENTER)
    rect(0, 0, 100, 100)
    popMatrix()
end

function Test2:key1()
    self.translateAnim = Animator(50, 100, 0.5, EASEIN, self.dokey2)
    self.scaleAnim = Animator(1, 0.7, 0.5, EASEIN)
end
function Test2:key2()
    self.translateAnim = Animator(100, 300, 1, EASENONE, self.dokey3)
    self.scaleAnim = Animator(0.7, 2, 0.5, EASEOUT)
end
function Test2:key3()
    self.translateAnim = Animator(300, 50, 1.5, EASEBOTH, self.dokey1)
    self.scaleAnim = Animator(2, 1, 0.5, EASEIN)
end