scenemanager.lua

--[[
SceneManager v1.0.4

changelog:
----------

v1.0.4 - 08.04.2012
Added option to filter a list of events during transitions
Moved increment of time to end of onEnterFrame so that time goes from 0 to 1
Added additional "real time" argument to dispatched transitions
Added option to pass user data to a scene when it gets created

v1.0.3 - 19.11.2011
Fixed incorrect calculation of width/height in landscape modes

v1.0.2 - 17.11.2011
Change event names

v1.0.1 - 06.11.2011
Add collectgarbage() to the end of transition

v1.0 - 06.11.2011
Initial release


This code is MIT licensed, see http://www.opensource.org/licenses/mit-license.php
(C) 2010 - 2011 Gideros Mobile
]]


SceneManager = Core.class(Sprite)

--[[
The following two deltas will correct the screen offsets for different screen sizes and
resolutions depending on a projects scale mode setting. Without them transitions between
scenes would take the wrong dimensions and end with ugly flickering or sudden disappearance
of objects.
]]
local dx = 2 * math.ceil(application:getLogicalTranslateX() / application:getLogicalScaleX())
local dy = 2 * math.ceil(application:getLogicalTranslateY() / application:getLogicalScaleY())


function SceneManager.moveFromRight(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	scene1:setX(-t * width)
	scene2:setX((1 - t) * width)
end

function SceneManager.moveFromLeft(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	scene1:setX(t * width)
	scene2:setX((t - 1) * width)
end

function SceneManager.overFromRight(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	scene2:setX((1 - t) * width)
end

function SceneManager.overFromLeft(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	scene2:setX((t - 1) * width)
end

function SceneManager.moveFromRightWithFade(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	scene1:setAlpha(1 - t)
	scene1:setX(-t * width)
	scene2:setX((1 - t) * width)
end

function SceneManager.moveFromLeftWithFade(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	scene1:setAlpha(1 - t)
	scene1:setX(t * width)
	scene2:setX((t - 1) * width)
end

function SceneManager.overFromRightWithFade(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	scene1:setAlpha(1 - t)
	scene2:setX((1 - t) * width)
end

function SceneManager.overFromLeftWithFade(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	scene1:setAlpha(1 - t)
	scene2:setX((t - 1) * width)
end

function SceneManager.moveFromBottom(scene1, scene2, t)
	local height = application:getContentHeight() + dy

	scene1:setY(-t * height)
	scene2:setY((1 - t) * height)
end

function SceneManager.moveFromTop(scene1, scene2, t)
	local height = application:getContentHeight() + dy

	scene1:setY(t * height)
	scene2:setY((t - 1) * height)
end

function SceneManager.overFromBottom(scene1, scene2, t)
	local height = application:getContentHeight() + dy

	scene2:setY((1 - t) * height)
end

function SceneManager.overFromTop(scene1, scene2, t)
	local height = application:getContentHeight() + dy

	scene2:setY((t - 1) * height)
end

function SceneManager.moveFromBottomWithFade(scene1, scene2, t)
	local height = application:getContentHeight() + dy

	scene1:setAlpha(1 - t)
	scene1:setY(-t * height)
	scene2:setY((1 - t) * height)
end

function SceneManager.moveFromTopWithFade(scene1, scene2, t)
	local height = application:getContentHeight() + dy

	scene1:setAlpha(1 - t)
	scene1:setY(t * height)
	scene2:setY((t - 1) * height)
end


function SceneManager.overFromBottomWithFade(scene1, scene2, t)
	local height = application:getContentHeight() + dy

	scene1:setAlpha(1 - t)
	scene2:setY((1 - t) * height)
end

function SceneManager.overFromTopWithFade(scene1, scene2, t)
	local height = application:getContentHeight() + dy

	scene1:setAlpha(1 - t)
	scene2:setY((t - 1) * height)
end

function SceneManager.fade(scene1, scene2, t)
	if t < 0.5 then
		scene1:setAlpha((0.5 - t) * 2)
	else
		scene1:setAlpha(0)
	end

	if t < 0.5 then
		scene2:setAlpha(0)
	else
		scene2:setAlpha((t - 0.5) * 2)
	end
end

function SceneManager.crossfade(scene1, scene2, t)
	scene1:setAlpha(1 - t)
	scene2:setAlpha(t)
end

function SceneManager.flip(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	if t < 0.5 then
		local s = (0.5 - t) * 2
		scene1:setScaleX(s)
		scene1:setX((1 - s) * width * 0.5)
	else
		scene1:setScaleX(0)
		scene1:setX(width * 0.5)
	end

	if t < 0.5 then
		scene2:setScaleX(0)
		scene2:setX(width * 0.5)
	else
		local s = (t - 0.5) * 2
		scene2:setScaleX(s)
		scene2:setX((1 - s) * width * 0.5)
	end
end

function SceneManager.flipWithFade(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	if t < 0.5 then
		local s = (0.5 - t) * 2
		scene1:setScaleX(s)
		scene1:setX((1 - s) * width * 0.5)
		scene1:setAlpha(s)
	else
		scene1:setScaleX(0)
		scene1:setX(width * 0.5)
		scene1:setAlpha(0)
	end

	if t < 0.5 then
		scene2:setScaleX(0)
		scene2:setX(width * 0.5)
		scene2:setAlpha(0)
	else
		local s = (t - 0.5) * 2
		scene2:setScaleX(s)
		scene2:setX((1 - s) * width * 0.5)
		scene2:setAlpha(s)
	end
end

function SceneManager.flipWithShade(scene1, scene2, t)
	local width = application:getContentWidth() + dx

	if t < 0.5 then
		local s = (0.5 - t) * 2
		scene1:setScaleX(s)
		scene1:setX((1 - s) * width * 0.5)
		scene1:setColorTransform(1 - t, 1 - t, 1 - t, 1)
	else
		scene1:setScaleX(0)
		scene1:setX(width * 0.5)
		scene1:setColorTransform(0.5, 0.5, 0.5, 1)
	end

	if t < 0.5 then
		scene2:setScaleX(0)
		scene2:setX(width * 0.5)
		scene2:setColorTransform(0.5, 0.5, 0.5, 1)
	else
		local s = (t - 0.5) * 2
		scene2:setScaleX(s)
		scene2:setX((1 - s) * width * 0.5)
		scene2:setColorTransform(t, t, t, 1)
	end
end

local function dispatchEvent(dispatcher, name)
	if dispatcher:hasEventListener(name) then
		dispatcher:dispatchEvent(Event.new(name))
	end
end

local function defaultEase(ratio)
	return ratio
end

function SceneManager:init(scenes)
	self.scenes = scenes
	self.tweening = false
	self.transitionEventCatcher = Sprite.new()
	self:addEventListener(Event.ENTER_FRAME, self.onEnterFrame, self)
end

function SceneManager:changeScene(scene, duration, transition, ease, options)
	self.eventFilter = options and options.eventFilter

	if self.tweening then
		return
	end

	if self.scene1 == nil then
		self.scene1 = self.scenes[scene].new(options and options.userData)
		self:addChild(self.scene1)
		dispatchEvent(self, "transitionBegin")
		dispatchEvent(self.scene1, "enterBegin")
		dispatchEvent(self, "transitionEnd")
		dispatchEvent(self.scene1, "enterEnd")
		return
	end

	self.duration = duration
	self.transition = transition
	self.ease = ease or defaultEase

	self.scene2 = self.scenes[scene].new(options and options.userData)
	self.scene2:setVisible(false)
	self:addChild(self.scene2)

	self.time = 0
	self.currentTimer = os.timer()
	self.tweening = true
end

function SceneManager:filterTransitionEvents(event)
	event:stopPropagation()
end

function SceneManager:onTransitionBegin()
	if self.eventFilter then
		stage:addChild(self.transitionEventCatcher)
		for i,event in ipairs(self.eventFilter) do
			self.transitionEventCatcher:addEventListener(event, self.filterTransitionEvents, self)
		end
	end
end

function SceneManager:onTransitionEnd()
	if self.eventFilter then
        	for i,event in ipairs(self.eventFilter) do
			self.transitionEventCatcher:removeEventListener(event, self.filterTransitionEvents, self)
		end
		self.transitionEventCatcher:removeFromParent()
	end
end

function SceneManager:onEnterFrame(event)
	if not self.tweening then
		return
	end

	if self.time == 0 then
		self:onTransitionBegin()
		self.scene2:setVisible(true)
		dispatchEvent(self, "transitionBegin")
		dispatchEvent(self.scene1, "exitBegin")
		dispatchEvent(self.scene2, "enterBegin")
	end

	local timer = os.timer()
	local deltaTime = timer - self.currentTimer
	self.currentTimer = timer

	local t = (self.duration == 0) and 1 or (self.time / self.duration)

	self.transition(self.scene1, self.scene2, self.ease(t), t)

	if self.time == self.duration then
		dispatchEvent(self, "transitionEnd")
		dispatchEvent(self.scene1, "exitEnd")
		dispatchEvent(self.scene2, "enterEnd")
		self:onTransitionEnd()

		self:removeChild(self.scene1)
		self.scene1 = self.scene2
		self.scene2 = nil
		self.tweening = false

		collectgarbage()
	end

	self.time = self.time + deltaTime

	if self.time > self.duration then
		self.time = self.duration
	end

end