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#### Overview of this book

SDL 2.0 is the latest release of the popular Simple DirectMedia Layer API, which is designed to make life easier for C++ developers, allowing you simple low-level access to various multiplatform audio, graphics, and input devices.SDL Game Development guides you through creating your first 2D game using SDL and C++. It takes a clear and practical approach to SDL game development, ensuring that the focus remains on creating awesome games.Starting with the installation and setup of SDL, you will quickly become familiar with useful SDL features, covering sprites, state management, and OOP, leading to a reusable framework that is extendable for your own games. SDL Game Development culminates in the development of two exciting action games that utilize the created framework along with tips to improve the framework.
SDL Game Development
Credits
www.PacktPub.com
Preface
Free Chapter
Getting Started with SDL
Drawing in SDL
Working with Game Objects
Exploring Movement and Input Handling
Handling Game States
Data-driven Design
Creating and Displaying Tile Maps
Creating Alien Attack
Creating Conan the Caveman
Index

## Setting up game objects for movement

In the previous chapter, we gave our objects x and y values which we could then use to pass into our drawing code. The x and y values we used can be represented using a Cartesian coordinate system.

The above figure shows a Cartesian coordinate system (flipped on the Y axis) with two coordinates. Representing them as (x,y) gives us position 1 as (3,3) and position 2 as (7,4). These values can be used to represent a position in 2D space. Imagine this figure as a zoomed in image of the top-left corner of our game window, with each of the grid squares representing one pixel of our game window. With this in mind, we can see how to use these values to draw things to the screen in the correct position. We now need a way to update these position values so that we can move our objects around. For this we will look at 2D vectors.

### What is a vector?

A vector can be described as an entity with a direction and a magnitude. We can use them to represent aspects of our game...