The reference of name x is looked up. The value at that reference is retrieved. The 3+1 calculation occurs, producing a new data element 4 which is assigned to a fresh memory location with a new reference. The name x is changed to point to this new reference. The old data 3 is garbage collected if no name still refers to it. If you use Microsoft Word (2007, 2011, 2013) build in reference (citation) manager you may encounter that not all modern reference styles are present. For example a common reference style “The Harvard referencing style” is not included by default in Word. BibMe.ORG bibliography Generator – APA 6th, MLA 8th, Chicago 17th/Turabian, Sage Harvard. TrafficLight is taking the security-while-browsing concept where it belongs: in the browser. This extension will add a strong layer of security over your browsing experience without inducing speed penalties or system resource consumption.

Today’s Topics

Lua
- This is the programming language that we’ll be using predominantly throughout the course. Lua is a dynamic scripting language similar to Python and JavaScript.
LÖVE2D
- The primary game framework we’ll be using throughout the course. It works hand in hand with Lua, and you can find documentation for it at love2d.org/wiki/Main_Page.
Drawing Shapes and Text
- Two of the most basic principles of game development, being able to draw shapes and text is what will allow us to render our game on a screen.
DeltaTime and Velocity
- DeltaTime, arguably one of the most important variables that we keep track of in any game framework, is the time elapsed since the last frame of execution in our game. LÖVE2D measures DeltaTime in terms of seconds, so we’ll see how this concept relates to velocity.
Game State
- Every game is composed of a series of states (e.g., the title screen state, gameplay state, menu state, etc.), so it will be important to understand this concept since we’ll want different rendering logic and update logic for each state.
Basic OOP (Object-Oriented Programming)
- The use of Object-Oriented Programming will allow us to encapsulate our data and game objects such that each object in our game will be able to keep track of all the information that is relevant to it, as well as have access to specific functions that are unique to it.
Box Collision (Hitboxes)
- Understanding the concept of box collision will be necessary in order to bring Pong to life, since we’ll need to be able to “bounce” a ball back and forth between two paddles. The ball and paddles will be rectangular, so we’ll focus on “Axis-Aligned Bounding Boxes,” which will allow us to calculate collisions more simply.
Sound Effects (with bfxr)
- Lastly, we’ll learn how to polish up our game with sound effects in order to make it more enticing and immersive.

Installing LÖVE2D

Before you start following along with the rest of the lecture, be sure to have LÖVE2D installed on your machine, which you can do through the following link:
- love2d.org/#download.
It’s available for all major operating systems (Windows, Mac, Linux). If you’re in need of some tips for how to get it started running on your machine, check out this link:
- love2d.org/wiki/Getting_Started.

Downloading Demo Code

Next, be sure to download the code for today’s lecture, which you can find at:
- github.com/games50/pong.
This should make it easier to follow along without having to focus on matching every keystroke in real time.

What is Lua?

“Lua” is Portuguese for “moon.” It was invented in 1993 in Brazil, and is intended for embedded use in larger applications. Since its invention, it has become very popular in the video game industry.
It is a flexible, lightweight scripting language focused around “tables,” which are similar to dictionaries in Python and objects in JavaScript.
Lua is excellent for storing data as well as code (it benefits from a>LÖVE2D is a fast 2D game development framework written in C++ that uses Lua as its scripting language.
It contains modules for graphics, keyboard input, math, audio, windowing, physics, and much more.
Fortunately, it is completely free and portable to all major desktops and Android/iOS.
It’s also great for prototyping if you don’t plan on using LÖVE2D in the final version of your game!

What is a game loop?

A game, fundamentally, is an infinite loop, like a while(true) or a while(1). During every iteration of that loop, we’re repeatedly performing the following set of steps:
- First, we’re processing input. That is to say, we’re constantly checking: has the user pressed a key on the keyboard, moved the joystick, moved/clicked the mouse, etc.?
- Second, we need to respond to that input from the previous step by updating anything in the game that depends on that input (i.e., tracking movement, detecting collisions, etc.).
- Third, we need to re-render anything that was updated in the previous step, so that the user can see visually on the screen that the game has changed and feel a sense of interactivity.
Photo taken from gameprogrammingpatterns.com/game-loop.html, where you can read more about game loops.

2D Coordinate System

In the context of 2D games, the most fundamental way of looking at the world is by using the 2D coordinate system.
Slightly different from the traditional coordinate system you might’ve used in math class, the 2D coordinate system we’re referring to here is a system in which objects have an X and Y coordinate (X, Y) and are drawn accordingly, with (0,0) being the top-left of the system. This means positive directions moving down and to the right, while negative directions move up and to the left.
Photo taken from rbwhitaker.wdfiles.com/local--files/monogame-introduction-to-2d-graphics/2DCoordinateSystem.png.

Today’s Goal

We are aiming to recreate “Pong,” a simple 2 player game in which one player has a paddle on the left side of the screen, the other player has a paddle on the right side of the screen, and the first player to score 10 times on their opponent wins. A player scores by getting the ball past the opponent’s paddle and into their “goal” (i.e., the edge of the screen).

Lecture’s Scope

First off, we’ll want to draw shapes to the screen (e.g., paddles and ball) so that the user can see the game.
Next, we’ll want to control the 2D position of the paddles based on input, and implement collision detection between the paddles and ball so that each player can deflect the ball back toward their opponent.
We’ll also need to implement collision detection between the ball and screen boundaries to keep the ball within the vertical bounds of the screen and to detect scoring events (outside horizontal bounds)
At that point, we’ll want to add sound effects for when the ball hits paddles and walls, and for when a point is scored.
Lastly, we’ll display the score on the screen so that the players don’t have to remember it during the game.

pong-0 (“The Day-0 Update”)

At this point, you will want to have downloaded the demo code in order to follow along. Be sure to pay attention to the comments in the code!
pong-0 simply prints “Hello Pong!” exactly in the center of the screen. This is not incredibly exciting, but it does showcase how to use LÖVE2D’s most important functions moving forward.

Important Functions

love.load()
- This function is used for initializing our game state at the very beginning of program execution. Whatever code we put here will be executed once at the very beginning of the program.
love.update(dt)
- This function is called by LÖVE at each frame of program execution; dt (i.e., DeltaTime) will be the elapsed time in seconds since the last frame, and we can use this to scale any changes in our game for even behavior across frame rates.
love.draw()
- This function is also called at each frame by LÖVE. It is called after the update step completes so that we can draw things to the screen once they’ve changed.
LÖVE2D expects these functions to be implemented in main.lua and calls them i

Easy Harvard Referencing For Os X