main.lua

-- 
-- Pick Your Poison.
-- Tutorial: Coding a game with the Ansca Corona SDK
-- 
-- Version: 1.0
-- 
-- Website: http://programmerdave.tumblr.com
-- Code is FreeBSD Licensed. 
-- Copyright 2011, David E. Rodriguez. All rights reserved.

---------- IMPORT MODULES ---------------
local physics = require("physics")
local audio = require("audio")

---------- MISCELLANEOUS  ---------------
math.randomseed( os.time(os.date("*t")) ) -- seed random number generator with the OS clock
display.setStatusBar( display.HiddenStatusBar ) -- Hide the status bar

---------- INITIALIZE VARIABLES  ---------------
local menu_img = nil -- On Screen Image Object
local background_img = nil -- On Screen Image Object
local player_img = nil -- On Screen Image Object

local scoreText = nil -- On Screen Text Object
local timeText = nil  -- On Screen Text Object 
local timeLeft = 0
local gameScore = 0
local gameOver = false 

local floor = nil -- An invisible rectangle that defines our floor
local player = "" -- This string is either "gates" or "jobs" depending on the character chosen

local gamePieceGroup = nil -- This DisplayGroup will keep all our game pieces in one place
local finalScoreText = nil -- On Screen Text Object

---------- LOAD SOUNDS  ---------------
local winSound = audio.loadSound("assets/win_sound.wav")
local loseSound = audio.loadSound("assets/lose_sound.wav")

---------- LOAD PHYSICS MODELS  ---------------
local physicsModels = (require "physicsModels").physicsData(1)

---------- CORONA REMOTE ----------------------
local remote = require("remote") -- Load The Remote
remote.startServer( "8080" ) -- Start The Remote On Port 8080

---------- FUNCTIONS  ---------------

-- Create the score and remaining time display objects
function createText() 

	scoreText = display.newText("Score: ", 10, 0, native.systemFont, 48)
	scoreText:setTextColor(255, 255, 255, 200)
	
	timeText = display.newText("Time Left: ", 10, 50, native.systemFont, 48)
	timeText:setTextColor(255, 255, 255, 200)
end

-- Create the player image and setup it's physics properties
function createPlayer( )
	
	-- load the player image
	if( player == "gates" ) then
	
		player_img = display.newImage( "assets/gates_player.png", true)
	
	else
	
		player_img = display.newImage( "assets/jobs_player.png", true)
		
	end
	
	-- Position the player
	player_img:setReferencePoint( display.BottomCenterReferencePoint )
	player_img.x, player_img.y = 320, 960
	
	player_img.collisionName = "player" -- Name to use when detecting collisions

	-- Add the physics model and make it kinematic so that we can control it
	if( player == "gates" ) then
		physics.addBody( player_img, "kinematic", physicsModels:get("gates_player"))
	else
		physics.addBody( player_img, "kinematic", physicsModels:get("jobs_player"))
	end
	
end

-- Creates an invisible rectangle for the floor
-- When an icon collides with this floor, it will be removed from the game
function createFloor () 
	
	floor = display.newRect( 0, 960, 640, 20 )
	floor:setFillColor(  255, 255, 255, 0)		-- make invisible by setting alpha to 0
	
	floor.collisionName = "floor" -- Name to use when detecting collisions

	-- add the physics model to the floor. 
	-- This is a sensor that only detects collisions and doesn't simulate any physics
	physics.addBody( floor, "static", { isSensor = true } ) 
end

-- Spawns a Game Piece from thin air.
-- Randomly generated and positioned.
-- Called every second until the game is over.
function spawnGamePiece()

	if( gameOver == true) then
		return
	end
		

	local pick_icon = math.random()
	local icon_img = nil
	
	-- Choose either the windows icon or the apple icon
	if( pick_icon > 0.5 ) then -- Choose the windows icon
	
		icon_img = display.newImage( "assets/windows_icon.png", true) -- Load the image

		icon_img.collisionName = "windows" -- Name to use when detecting collisions
	
	else -- Choose the apple icon
	
		icon_img = display.newImage( "assets/apple_icon.png", true) -- Load the image
		
		icon_img.collisionName = "apple" -- Name to use when detecting collisions
		
	end
	
	-- Add the gamePiece to the gamePiece Display Group
	gamePieceGroup:insert(icon_img)

	-- Position icon into place randomly
	local x, y = math.random(120, 640 - 120), -60
	icon_img.x, icon_img.y = x, y
		
	-- Add Physics Model to the Icon
	if( pick_icon > 0.5 ) then -- Choose the windows icon
	
		physics.addBody( icon_img, physicsModels:get("windows_icon") ) -- add the physics model
		
	else -- Choose the apple icon
	
		physics.addBody( icon_img, physicsModels:get("apple_icon") ) -- add the physics model
		
	end

	timer.performWithDelay( 1000, spawnGamePiece ) -- Call this method again in a second
end

-- Changes the text on screen with the current score and time remaining
function updateScoreAndTimeText()
	scoreText.text = "Score: " .. gameScore
	scoreText:setReferencePoint(display.CenterLeftReferencePoint)
	scoreText.x = 10
	
	timeText.text = "Time Left: " .. timeLeft
	timeText:setReferencePoint(display.CenterLeftReferencePoint)
	timeText.x, timeText.y = 10, 100
end

-- This timer is called every second to keep track of the remaining time in the game
function updateGameTimer( event )
	
	timeLeft = timeLeft - 1 -- subtract a second from the remaining time
		
	if( timeLeft <= 0 ) then
		gameOver = true -- Done with game
	else
		updateScoreAndTimeText()

 		timer.performWithDelay( 1000, updateGameTimer ) -- Call this method again in a second
	end
end

-- This method is called when a collision occurs between any two objects
function onCollision( event )
	-- The collision just began
	if ( event.phase == "began" ) then
		
		-- Check if there was a collision between the floor and an icon
		if( event.object1.collisionName == "floor" or event.object2.collisionName == "floor" ) then
		
			-- If the icon collided with the floor, remove it from the display
			-- This will also remove it from the physics simulation
			if( event.object1.collisionName == "apple" or event.object1.collisionName == "windows" ) then
			
				print("Icon Disappeared")
				event.object1:removeSelf()
				
			elseif( event.object2.collisionName == "apple" or event.object2.collisionName == "windows" ) then
			
				print("Icon Disappeared")
				event.object2:removeSelf()
				
			end
			
		-- Check if there was a collision between the player and an icon
		elseif( event.object1.collisionName == "player" or event.object2.collisionName == "player" ) then
		
			-- If the icon collided with the player, udpate the score, then remove it from display
			-- Also plays a sound and either increases or decreases the score based on the player type
			if( event.object1.collisionName == "apple" or event.object2.collisionName == "apple" ) then
			
				print("Player Captured Apple")
				
				-- Update Score
				if( player == "gates" ) then -- apples are bad for Bill Gates
					gameScore = gameScore - 1
					audio.play(loseSound)
				else
					gameScore = gameScore + 1
					audio.play(winSound)
				end
				
				-- Remove the icon from display
				if( event.object1.collisionName == "apple" ) then
					event.object1:removeSelf()
				else
					event.object2:removeSelf()
				end
				
			elseif( event.object1.collisionName == "windows" or event.object2.collisionName == "windows" ) then
			
				print("Player captured Windows")
				
				-- Update Score
				if( player == "jobs" ) then -- windows are bad for Steve Jobs
					gameScore = gameScore - 1
					audio.play(loseSound)
				else
					gameScore = gameScore + 1
					audio.play(winSound)
				end
				
				-- Remove the icon from display
				if( event.object1.collisionName == "windows" ) then
					event.object1:removeSelf()
				else
					event.object2:removeSelf()
				end
				
			end
		end
		
	end
end

-- This method is called to handle a touch event.
-- In the main menu, if you touch the left side of the screen, you'll pick Bill Gates
-- In the main menu, if you touch the right side of the screen, you'll pick Steve Jobs
function buttonHandler( event )
	
	-- If we touched the screen then released. Ended the Touch.
	if( event.phase == "ended" ) then
	
		if( event.y > 250 ) then -- Make sure we touched below the game title
			
			if( event.x <= 320 ) then	-- Left half of the screen picks Bill Gates
			
				player = "gates"
				startGame() -- Begin the game
				
			else						-- Right half of the screen picks Steve Jobs
				
				player = "jobs"
				startGame() -- Begin the game
				
			end
			
		end
	
	end
end

-- Show the main menu
function showMenu()
	
	menu_img = display.newImage( "assets/menu.png" , true) -- display the menu background image
	Runtime:addEventListener( "touch", buttonHandler ) -- register to receive touch events
	
end

-- This method is called to finish cleaning up the game and go back to the main menu.
function endGame( )
	
	-- Finish cleaning up game
	background_img:removeSelf()
	background_img = nil
	
	player_img:removeSelf()
	player_img = nil
	
	finalScoreText:removeSelf()
	finalScoreText = nil
	
	gamePieceGroup:removeSelf()
	gamePieceGroup = nil
	
	timeLeft = 0
	gameScore = 0
	gameOver = false
	
	floor:removeSelf()
	floor = nil
	
	showMenu()
end

-- This method is called when the timer runs out to show the final score
function showFinalScore() 

	-- Clean up some parts of the current game
	
	Runtime:removeEventListener( "collision", onCollision ) -- Stop listening to collision events
	Runtime:removeEventListener( "enterFrame" , updateGame ) -- Stop updating the game every frame
	
	-- Remove the onscreen text objects
	scoreText:removeSelf()
	scoreText = nil
	
	timeText:removeSelf()
	timeText = nil
	
	-- Initialize and show the final score in the middle of the screen
	finalScoreText = display.newText("Score: " .. gameScore, 0, 0, native.systemFont, 100)
	finalScoreText:setTextColor(255, 255, 255, 200)
	
	finalScoreText:setReferencePoint(display.CenterReferencePoint)
	finalScoreText.x, finalScoreText.y = 320, 480
end

-- Updates the game status and moves the player on every frame
function updateGame( event )

	if( gameOver == true ) then
		-- Show the score and wait 5 seconds before returning to the menu
		showFinalScore()
		
		-- Register to call gameTime's timer method every second
 		timer.performWithDelay( 5000, endGame )
		return
	end
	
	-- Update the text on the screen
	updateScoreAndTimeText()
	
	-- Move character based on gravity
	player_img:translate( remote.xGravity*90, 0 )
	
	-- Keep the player inside the screen bounds
	if( player_img.x < -100 ) then
		player_img.x = -100
	end
	
	if( player_img.x > 640 + 100 ) then
		player_img.x = 640 + 100
	end
	
end

-- Starts the Physics Engine and Sets the Gravity for the Game
function startPhysics() 
	-- Start the physics simulation
	physics.start()
	
	physics.setScale( 60 ) -- resolution of physics simulation
	physics.setGravity( 0, 9.8 ) -- set gravity to point down
end

-- This method will start a new game.
function startGame( )
	
	-- Clean up menu
	Runtime:removeEventListener( "touch", buttonHandler )
	menu_img:removeSelf()
	menu_img = nil
	
	-- Load the game background
	background_img = display.newImage( "assets/background.png", true)
	
	-- Initialize the Display Group to keep our icons in one place
	gamePieceGroup = display.newGroup()
	
	-- Start the physics engine
	startPhysics()
	
	-- Create the player object
	createPlayer()
	
	-- Create the on screen text objects
	createText()
	
	-- Create the game floor
	createFloor()
	
	-- Initialize Game Status
	gameOver = false
	timeLeft = 30
	gameScore = 0
	
	-- Register to detect collisions
	Runtime:addEventListener( "collision", onCollision )
	
	-- Register to update the game on every frame
	Runtime:addEventListener( "enterFrame" , updateGame )
	
	-- Start updating the game timer every second
	updateGameTimer()
	
	-- Start spawning game pieces every second
	spawnGamePiece()
end
	

---------- LAUNCH THE MAIN MENU --------------

showMenu()