laser-cannon.lua

-- The laser cannon can move in the X direction with a fixed Y position.
-- Handle health / movement / laser firing.
local Laser = require('laser')
local glo = require('globals')
local screen = glo.screen
local PADDING = 0
local TEXT_PADDING = 20
-- constants
local SPEED = 7
local dir = ""

-- define body rectangle
local hitsTaken = 0
local maxHealth = 3
local body = display.newRect(screen.xCenter, display.contentHeight + 20, 40, 20)
body.isCannon = true
physics.addBody(body,"kinematic")

function body.onCollision(event)
	
	hitsTaken = hitsTaken + 1
	print(hitsTaken)
	if hitsTaken > maxHealth then
		print("Dead")
	end
	
	if hitsTaken > maxHealth then
		lifeCounter.text = "GAME OVER!"
	else
		lifeCounter.text = "Lives:  "..maxHealth - hitsTaken
	end

end

lifeCounter = display.newText{
	text = "Lives:  "..maxHealth - hitsTaken,
	x = glo.screen.xMax - glo.screen.xCenter/3 - TEXT_PADDING,
	y = glo.screen.yMin + TEXT_PADDING,
	font = native.systemFont,
	fontSize = 20,
}

local function move(direction)
	dir = direction
end

local function updateMovement()
	if dir == "left" and body.x > body.width / 2 then
		body.x=body.x-SPEED
	elseif dir == "right" and body.x < screen.width - body.width / 2 then
		body.x=body.x+SPEED
	end
end

local function moveLeft(event)
	if event.phase == "began" then	
		move("left") 
	elseif event.phase == "ended" then
		move("")
	end
end

local function moveRight(event)
	if event.phase =="began" then
		move("right")
	elseif event.phase == "ended" then
		move("")
	end
end

 function shootUp(event)
 	if event.phase == 'began' then
		local l = Laser:new(body.x, body.y - body.height - PADDING, "up")
		l:fire()
	end
end
--shootUp()
function keyPress(event)
	if event.phase == "down" then
		if event.keyName == "up" or event.keyName == "space" then
			local l = Laser:new(body.x, body.y - body.height - PADDING, "up")
			l:fire()
		else
			move(event.keyName)
		end
	elseif event.phase == "up" then
		move("")
	end
end

-- attach the movement function to it's corresponding button in the 'buttons' api.
local buttons = require("buttons")
buttons.left_arrow:addEventListener("touch", moveLeft)
buttons.right_arrow:addEventListener("touch", moveRight)
Runtime:addEventListener("key", keyPress)
Runtime:addEventListener("enterFrame", updateMovement)

-- TODO:
	
	-- Add keyboard functionality to make testing/playing on a computer easier.