SDL Extension Library

NEWS:

01-27-2002    Version 0.1.6 Released.      [What's new]

01-25-2002    Version 0.1.5 Released.      [What's new]

10-27-2001    Version 0.1.4 Released.      [What's new]

09-16-2001    Version 0.1.3 Released.      [What's new]

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What is SEL?

SEL is a C++ library that extends and wraps the SDL library. The SDL library is a generic low level multiplatform api for accessing audio, keyboard, mouse, joystick, threads, 3d hardware via OpenGL, and 2d framebuffer.

SEL stands for Simple DirectMedia Layer Extension Library. The purpose of SEL is to provide a C++ interface for the SDL library and to extend it's functionality.

SEL tries to be as much backwards compatible with SDL as possible, while introducing native C++ features as namespaces, classes, and exceptions. SEL should also run on as many platforms as SDL does.

Key features

SDL wrapper
Basic graphic primitives drawing (SEL::Painter)
- lines, rectangles, ...
- opaque or alpha blended
Bitmap font manipulation class (SEL::Font)
- simple font creation
Resource management
- load the resources from separate files according to the resource script
- compile the resources in one data file
Animation abstraction (SEL::Animation)
Miscelanous functionality
- SEL::Uta class for microtile arrays manipulation
- ...

SEL consists of four separate (but not independent) libraries. These are:

libSEL_base - basic functionality, SDL wrapper
libSEL_painter - SEL::Painter and SEL::Font classes
libSEL_resource - the resource management system
libSEL_resources - the default resource types

The compiler and linker flags can be retrieved using the sel-config script.

SEL consists of three (logical) parts (or layers).

Translation of the SDL identifiers
The actual SEL wrappers
Additional classes

1. Translation of the SDL identifiers

In SEL each SDL identifier that begins with SDL_ belongs to the SDL namespace. (i.e. SDL_Surface is SDL::Surface, SDL_SetVideoMode is SDL::SetVideoMode, but SDL_ALPHA_OPAQUE is SDL::ALPHA_OPAQUE and not SDL::ALPHA::OPAQUE.)

The namespace SDL also contains "sub" namespaces WM and GL for window manager and open gl related functions.

Note that identifiers SDL::Surface and SDL_Surface are equal. It does not matter whether you use SDL::Surface or SDL_Surface in your code. But I prefer SDL::Surface to SDL_Surface in C++ code, because it makes the code more consistent.

All identifiers from the SDL namespace are just directly translated SDL identifiers and do not provide any enhanced functionality or API changes. The SDL namespace provides no classes, and does not wrap any SDL objects. No function from the SDL namespace throws an exception.

Since all the translation fuctions are inlined, the speed penalty should be minimal. See the file SEL_sdl.h to see how it exactly works.

2. The actual SEL wrappers and extension classes.

As opposite to the identifiers from the SDL namespace, the SEL namespace contains higher level wrappers of the SDL objects.

So the difference between SDL::Surface and SEL::Surface (or just Surface, if you are `using namespace SEL') should be obvious. While the SDL::Surface is just a SDL_Surface structure, the SEL::Surface is a full featured class that takes advantage of the neat C++ features like exceptions, etc.

For more information about particular classes from the SEL namespace consult the SEL refrence documentation.

3. Additional classes.

SEL also contains some classes to simplify common things such as drawing basic graphic primitives or text, managing resources or merging dirty rectangles. Some of these are mentioned here. Consult the SEL refrence documentation for more info.

SEL::Painter - drawing basic graphic primitives

This class implements drawing of lines and rectangles with support of alpha-blending.

SEL::Resource - resource management

See the demo to find out how this works.

SEL::Uta - microtile arrays (region management)

This is one of the most powerfull ways of managing dirty rectangles. It's very fast and produces optimized set of non-overlapping rectangles. However, the area covered by the resulting rectangles is ussualy little bigger than the original area.

Despite it's low version number, the SEL now wraps about 85% of the SDL functionality. SDL audio and overlays are still to be wrapped.

But the goal of SEL is not just to wrap SDL. It's to provide an extension layer, classes that would seamlessly integrate with the current wrappers.

The SEL has not been extensively tested yet so all testers (as well as any other help) are welcome.

I would appreciate help of any kind (comments, bugfixes).

The documentation itself needs also some corrections (a lot of...). If you find some bugs, grammar mistakes or parts of the documentation that are not clean enough, please let me know. (If you found nothing it means that you have not read the documentation :)

The SEL is distributed under the terms of the GNU Library General Public Licence. It means that you can use the SEL library for both free and commercial purposes as long as you link you program with it dynamically. See the COPYING file in the source root directory or the licence here for more information.

The latest version of SEL is 0.1.6. It's a development version, but it should be usable yet. You can download the file here. The tarball contains the library source code and the documentation.

SEL requires the SDL library (version 1.2.0 or higher) and the SDL_Image library.

The SEL has a html reference documentation which can be viewed online here.