SDL Wrappers for Euphoria

1^st version notes

July 1, 2002

Greetings!

This is the first version of my SDL wrappers for the Euphoria programming language. Before we delve into details some definitions are in order. SDL is short for Simple Directmedia Layer, a library for programming games and multimedia applications that includes functions for graphics, sounds, controllers (joystick/mouse/keyboard) and CD audio. The SDL wrapper file makes the SDL library functions accessible form Euphoria. SDL was written by Sam Lantinga and is distributed under the GNU Lesser Public License.

The official SDL website http://www.libsdl.org contains more information both general and specific.

What you need to get started…

The following files are included with this SDL wrapper package:

README.TXT – this file in plain text form

README.HTML – this file in HTML form

SDL.DLL – The actual SDL dynamic link library

SDL_WRAP.EW – The Euphoria wrapper include file

SDLDEX01.EXW – Demo program 1: makes kaleidoscopic pictures

SDLDEX02.EXW – Demo program 2: Galton box simulation

SDLDEX03.EXW – Demo program 3: the swirling arcs

SDLDEX04.EXW – Demo program 4: Change the cursor to a smiley

SDLDEX05.EXW – Demo program 5: Scrolling map demo

SDLDEX06.EXW – Demo program 6: Controller input demo

BITMAPS – a folder containing the images used by the demo programs

The demo programs are quick examples of how to use the SDL library. You can quit any of the Demos by pressing the Escape [Esc] key. You can also press either mouse button to quit in every demo except SDLEX04. In SDLEX04 pressing the mouse buttons will cause the smiley to blink. In SDLEX05 you can use the arrow keys to scroll the map. In SDLEX06 use the arrow keys to move the “Keys” object and the mouse or joystick (if attached) to move the others.

Feel free to use the SDL_WRAP file in your own projects. If you write a game or application program that includes the SDL_WRAP.EW file, make sure to credit me (Mark K. Akita) somewhere in the help, docs or “about” screen.

Writing your own SDL programs in Euphoria…

You’ll need a moderate amount of Euphoria programming knowledge to use the SDL library in your own programs. You can get a copy of the complete SDL documentation from http://sdldoc.csn.ul.ie/pub/ in PDF or HTML form. The SDL docs contain descriptions of all the functions and examples in C. You can also study the SDLDEX01-06 demo programs for specific examples of how to call the various SDL functions from Euphoria. The demos don’t use every available SDL function but should provide a basic framework for creating programs. SDL programs written in Euphoria are for the Win32 OS rather than DOS and should have an EXW extension. All of the SDL functions called through SDL_WRAP use a standard Euphoria function call rather than a C_PROC or C_FUNC call. Euphoria PEEK and POKE functions are used to simulate C structures.

Nearly all of the SDL functions included in the wrapper are working. The notable exceptions are functions that require callbacks. While C handles passing callback addresses effortlessly I was unable to get Euphoria to properly send a callback address. The main functions affected by the callback problem are:

SDL_OpenAudio

SDL_CreateThread

SDL_AddTimer

Maybe some wise Euphoria guru will know how to get around the callback problem and will upload a patch for the wrappers.

What else?

Currently I have 3 other SDL/Euphoria projects in various stages of completion:

The Euphoria wrapper file for the SDL_MIXER library, which adds MIDI/MOD music and multiple channels of audio sample playback to SDL, will be finished soon.

A series of examples showing how to use Open GL with SDL is also in the works. Right now I have a few of the demos converted from C and I’m working on the others.

I’ve also started work on a game program that uses SDL and SDL_MIXER.

That’s All Folks!

Send comments & feedback to mkakita@earthlink.net