Using FMOD, SDL, and tinyPTC in FreeBASIC
This is an excerpt from an article published in QBXL Magazine, with permission by SJ Zero, the author.
FreeBASICs greatest strength is it's ability to seamlessly integrate with a number of standard C libraries while maintaining the ease of use that is QB. Even before FB had a built-in graphics library, intrepid coders were using SDL to get graphics and sound routines working. Before the current version included a SDL_net and Winsock, a number of coders, myself included, fought with the headers to get network support into FreeBASIC. Today, I'm just going to cover how to get started with three advanced libraries: SDL, fmod, and tinyPTC. After understanding the fundamentals, you'll see that using C libraries is simple enough that with few exceptions, C libraries are no more difficult to use in FreeBASIC than QB libraries were to use.
What are these Libraries, Anyway?
These libraries are particularly useful because they tend to provide functions for games.
TinyPTC is primarily a graphics library, the simplest one available. It does little more than give you a pointer to the graphics reigon to draw to.
FMod is a 3d sound and music library. Though its license is strange, it works acceptably for playing sounds, and it nicely encapsulates 3D sound.
Including the Library
The first step in getting any of these libraries to work is including their header files in your project. For SDL, it's simply
For FMOD, it's
and for tinyPTC, you'll want
2. Initilizing the library, loading a file
Obviously, you can't just include the lib and fire away if it's got to do stuff first. To initilize SDL and load a bitmap into memory, you must:
CONST SCR_WIDTH = 640 CONST SCR_HEIGHT = 480 DIM MenuScreen AS SDL_Surface PTR DIM bitmap AS SDL_Surface ptr 'our bitmap DIM video AS SDL_Surface ptr 'our screen surface SDL_Init ( SDL_INIT_VIDEO ) video = SDL_SetVideoMode( SCR_WIDTH, SCR_HEIGHT, 32, 0 ) 'sets the video mode for 640x480x32 MenuScreen = SDL_LoadBMP("bitmap.bmp")
To initilize FMOD and load a sound into memory, you must:
DIM sound AS FSOUND_SAMPLE ptr 'Use the appropriate pointer type, because FB V0.17 and above is sensitive to this! IF FSOUND_GetVersion <= FMOD_VERSION THEN ErrorQuit "FMOD version " + STR$(FMOD_VERSION) + " or greater required" End If If FSOUND_Init(44100, 32, 0) = FALSE Then ErrorQuit "Can't initialize FMOD" End If sound = FSOUND_Sample_Load(FSOUND_FREE,"sound.wav", FSOUND_HW3D, 0, 0)
Finally, there's no data formats to load with tinyPTC because it's so simple, but you initilize it by going:
const SCR_WIDTH = 320 const SCR_HEIGHT = 200 const SCR_SIZE = SCR_WIDTH*SCR_HEIGHT if( ptc_open( "tinyPTC test", SCR_WIDTH, SCR_HEIGHT ) = 0 ) then end -1 end if
Blitting, Playing, or Plotting
The most important step, obviously, is to get whatever you want to do to the screen or speakers. This part is relatively easy, and can be encapsulated further into a wrapper function. For SDL, sending an image to the screen means going:
SUB BlitImage(x as integer,y as integer,image as sdl_surface ptr) DIM Rectangle as SDL_Rect DIM Rectangle2 as SDL_Rect Rectangle.X = 0 Rectangle.Y = 0 rectangle.w = image->w rectangle.h = image->h Rectangle2.x = x Rectangle2.y = y SDL_BlitSurface image, @rectangle, screenSurface, @rectangle2 END SUB
For FMOD, the steps to play a sound aren't that difficult either:
FUNCTION fModPlayWave( samp1 as FSOUND_SAMPLE ptr) AS FSOUND_SAMPLE ptr 'where samp1 is the number returned by FSOUND_SampleLoad DIM position(0 to 2)' as FSound_Vector DIM vel(0 to 2)' FSound_Vector fModPlayWave = FSOUND_PlaySoundEx(FSOUND_FREE, samp1, NULL, TRUE) END FUNCTION
And TinyPTC, which is again, not a high level library like the other two, can plot pixels using the following code:
SUB putd(BYREF buffer(), BYVAL x AS INTEGER, BYVAL y AS INTEGER, BYVAL colr as INTEGER) buffer((y * SCR_WIDTH) + x) = colr ptc_update @buffer(0) 'This is a pageFlip END SUB
So you don't have to manage memory and do all the boring mundane tasks, you must remember to shut down the library before your program exits. Luckily, all three programs allow this with one line. If you can't shut it down, the library no longer cares. It's beautiful.
SDL: SDL_Quit () fmod: FSOUND_Close () tinyPTC: PTC_Close ()
That's all there is to quitting! As you can see, there is nothing inherently more difficult in using libraries in FreeBASIC compared to QuickBASIC. In fact, because coders don't need to jump through hoops to get to memory, it's actually much easier, even with the more modern OS and hardware.