Game programmers using OpenGL have often been forced to make a choice between using a library that is platform independent but doesn't use all the available resources, or powerful but platform dependent. Simple Directmedia Layer (SML) offers a third way. This article will give you a taste of its capabilities.
The implementation works in such a way that it never gets in the way of a programmer's code, as is evident from the services provided by SDL. In a nutshell one can say that it follows the philosophy of SMILE (Simple Makes It a Lot Easier) which is evident from the following services provided by it:
Initialization and Shutdown
Of these services, the first five are the basis of any game. SDL makes dealing with each of them easier. Let's see how.
Initialization and Shutdown:
Whenever a game starts, it must perform initialization routines including memory allocation, resource acquisition, loading any required data from the disk, and so forth. To perform these routines, the programmer has to query the underlying OS to know the boundaries set by it. To achieve this end some code must be written, and code must be written again to use the result of the query. SDL abstracts this with a single function: SDL_Init().
In a gaming environment the input can come from the keyboard, joystick, mouse and so on. The processing model provided by SDL is event based. Anyone who has worked in VB, Delphi or Xlib (or any of its variants) will feel at home with SDL's event model. The base of this model is the SDL_WaitEvent() method that takes SDL_Event as a reference.
Without timers it is nearly impossible to imagine any challenging game. If one goes by standard methods, one would have to rely on the timers provided by the platform. But with SDL, this is a thing of past. The Time and Timer APIs provided by it are lean, mean and clean in a platform and OS independent way. SDL_getTicks() is the core of the SDL Timer API.
As with other functionalities provided by SDL, the functionalities related to sound are provided with minimum hassles. The sound support as a core sub-system is minimal in nature, adhering to the keep-it-lean philosophy of SDL. But there are other libraries that provide extended capabilities around SDL's APIs.
With SDL one has the option of working at the raw pixel level or at a higher level using OpenGL. Since OpenGL is available for every platform and it can render both 2D and 3D graphics in hardware accelerated mode, it is better to use OpenGL in conjunction with SDL.
Like other functionalities, networking is also important in the current genre of games. Understanding this importance, the developers of SDL provided an APIs that does the ground-level work to set up the network connections and manage them, thus making networked multiplayer games less of an enigma.
The pthreads library provided by POSIX is a platform independent way of working with threads. But the API works at a low level, which can be confusing. To make threading simpler, SDL provides all the required functionalities in a high-level manner.
In essence, SDL provides for all gaming requirements in a simple and portable way. Now that the introduction to the functionalities is out of our way, we can actually see how the theory works by looking at how handling the video subsystem works.