What is SFML?

Before we start throwing terms and code your way, it's only fair we talk a little bit about the choice library for this book. As its title clearly states, SFML is a library, which speeds up and eases the process of developing applications that rely on extensive use of media content, such as video, text, still images, audio, and animation for interactivity, and we will be focusing on a specific category of those applications, that is, video games. It provides an easy to use application programming interface (API), compiles and runs out of the box on Windows, Linux, and Mac OS X, and is supported by multiple languages, such as C, .NET, C++, Java, Ruby, Python, and Go, just to name a few. Unofficial ports for certain mobile devices do exist out there, however official releases for mobile platforms are still in the works. It's also open source, so one can always go and look at the source code if one is so inclined. In this book, we will be focusing solely on development for the Windows platform using C++11.

For convenience, SFML is split into five modules, which are independent of one another and can be included on a need-to-use basis:

• System: A core module, which defines most basic data structures, provides access to threads, clocks, user data streams, and other essentials.
• Window: This module provides a means of creating and managing a window, gathering user input and events, as well as using SFML alongside OpenGL.
• Graphics: Everything left to be desired graphically after fully utilizing the window module falls back on the graphics module. It deals with everything concerning two-dimensional rendering.
• Audio: Anything to do with playing music, sounds, audio streams, or recording audio is handled by this module.
• Network: The last but definitely not the least interesting module that covers sending data to other computers as well as working with a few networking protocols.

Each one of these modules is compiled in a separate library (.lib) with specific postfixes that signify whether the library is being linked statically or dynamically, as well as if it's being built in debug or release mode. Linking a library statically simply means that it gets included in the executable, as opposed to dynamic linking, where .dll files are required to be present in order for the application to run. The latter situation reduces the overall size of the application by relying on the library being present on the machine that runs it. It also means that the library can be upgraded without the need to alter the application, which can be useful when fixing bugs. Static linking, on the other hand, allows your code to be executed in environments that are more limited.

It's also important to make sure that your application is being built in a mode that's suitable for the situation. Debug mode applications are bloated with additional information that is useful when you're hunting down flaws in your programs. This makes the application run considerably slower and shouldn't be used for any other purposes than testing. When building your project in release mode, tons of different optimizations are also turned on, which not only provides a smaller executable footprint, but also a much faster running speed. This should be the mode an application is compiled in, if it is to be released for any kind of use other than debugging.

Each module is named according to the format sfml-module[-s][-d].lib. For example, the file name of a graphics library that is being linked statically and compiled in debug mode would look like this: sfml-graphics-s-d.lib. When linking dynamically or compiling in release mode, the postfixes need to be omitted. SFML also requires the SFML_STATIC macro to be defined when linking statically, which we will cover shortly when setting up our first project.

An important thing to keep in mind about the separate libraries is that they still have dependencies. Window, graphics, audio, and network libraries are dependent on the system library, which has to be linked to for any SFML application to compile and run. The graphics library is also dependent on the window library, so all three have to be linked to if an application does any drawing. The audio and networking libraries only depend on the system library.

Note

Since version 2.2, when linking SFML statically, its dependencies must also be linked to the project. These dependencies vary between major versions 2.2 and 2.3, so we're going to stick with the newest version, that is, 2.3. The graphics library requires opengl32.lib, freetype.lib, and jpeg.lib libraries. The window library depends on opengl32.lib, winmm.lib, and gdi32.lib. Linking to the system library only requires the winmm.lib library, while sfml-network-s.lib relies on ws2_32.lib in order to work. Lastly, the sound library depends on openal32.lib, flac.lib, vorbisenc.lib, vorbisfile.lib, vorbis.lib, and ogg.lib.

Each one of these five modules has a corresponding header that must be included to utilize its functionality. For example, including the graphics header would look like this:

#include <SFML/Graphics.hpp>

It is also possible to avoid including the entire module header by specifying the actual header that is desired within a module:

#include <SFML/Graphics/Color.hpp>

This gives you a chance to include only the parts that are absolutely necessary.

Note

It's best practice to use forward slashes when including libraries. Different operating systems do not recognize paths that have a backslash in them.