[SDL] Weirdness with SDL_GetVideoInfo and Joystick

[Bob Pendleton]

On Thu, 2004-08-26 at 05:15, Tyler Olsen wrote:
> I've been working with SDL for 2 months and so far everything seems to 
> be working great, but a couple days ago I wrote a function to try 
> printing out information about my system and I got some really 
> unexpected results. Here is the C++ code (this is for Debian Linux):
> 
> 
>    cout << "_____Printing system information_____" << endl;
> 
>    // Initialize SDL and its subsystems and make sure it shutdowns 
> properly on exit
>    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_JOYSTICK) != 0) {
>      cout << "ERROR: Unable to initialize SDL: " << SDL_GetError() << endl;
>      return;
>    }
>    else
>      cout << "SDL Initialized succesfully." << endl;
>    atexit(SDL_Quit);
> 
>    // Video Information
>    cout << " *** VIDEO INFORMATION *** " << endl;
>    char video_driver[20];
>    SDL_VideoDriverName(video_driver, 20);
>    cout << "Video driver name: " << video_driver << "\n" << endl;
> 
>    const SDL_VideoInfo *user_video;
>    user_video = SDL_GetVideoInfo(); // Get information about the user's 
> video system
>    cout << "Best available video mode" << endl;
>    cout << ">Creates hardware surfaces: ";
>    if (user_video->hw_available == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Has window manager available: ";
>    if (user_video->wm_available == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Hardware to hardware blits accelerated: ";
>    if (user_video->blit_hw == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Hardware to hardware colorkey blits accelerated: ";
>    if (user_video->blit_hw_CC == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Hardware to hardware alpha blits accelerated: ";
>    if (user_video->blit_hw_A == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Software to hardware blits acceleerated: ";
>    if (user_video->blit_sw == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Software to hardware colorkey blits accelerated: ";
>    if (user_video->blit_sw_CC == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Software to hardware alpha blits accelerated: ";
>    if (user_video->blit_sw_A == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Color fills accelerated: ";
>    if (user_video->blit_fill == 1) cout << "yes\n";
>    else cout << "no\n";
>    cout << ">Total video memory: " << user_video->video_mem << " 
> kilobytes" << "\n" << endl;
> 
>    // Joystick Information
>    cout << " *** JOYSTICK INFORMATION *** " << endl;
> 
>    int js_num = SDL_NumJoysticks(); // Get the number of joysticks available
>    cout << "SDL has recognized " << js_num << " on this system." << endl;
>    for (int i = 0; i < js_num; i++) { // Print out information about 
> each joystick
>      joy_stick = SDL_JoystickOpen(i);
>      if (joy_stick == NULL)
>        cout << "ERROR: SDL was unable to open joystick #" << i << endl;
>      else {
>        cout << "Joystick #" << i << endl;
>        cout << ">Name: " << SDL_JoystickName(i) << endl;
>        cout << ">Axes: " << SDL_JoystickNumAxes(joy_stick) << endl;
>        cout << ">Buttons: " << SDL_JoystickNumButtons(joy_stick) << endl;
>        cout << ">Trackballs: " << SDL_JoystickNumBalls(joy_stick) << endl;
>        cout << ">Hat Switches: " << SDL_JoystickNumHats(joy_stick) << endl;
>        SDL_JoystickClose(joy_stick);
>      }
>    }
> 
> 
> 
> Here is the output from the program:
> 
> _____Printing system information_____
> SDL Initialized succesfully.
>   *** VIDEO INFORMATION ***
> Video driver name: x11
> 
> Best available video mode
>  >Creates hardware surfaces: no
>  >Has window manager available: yes
>  >Hardware to hardware blits accelerated: no
>  >Hardware to hardware colorkey blits accelerated: no
>  >Hardware to hardware alpha blits accelerated: no
>  >Software to hardware blits acceleerated: no
>  >Software to hardware colorkey blits accelerated: no
>  >Software to hardware alpha blits accelerated: no
>  >Color fills accelerated: no
>  >Total video memory: 0 kilobytes
> 
>   *** JOYSTICK INFORMATION ***
> SDL has recognized 0 on this system.
> 
> 
> 
> I tried calling SDL_SetVideoMode before I call SDL_GetVideoInfo(), but I 
> got the same results for the video information. I have a Radeon 9500PRO 
> video card and I have successfuly installed the ATI drivers so I don't 
> know how I could have 0KB of video memory (-_-'). Does anyone know what 
> the problem is here?

Mostly it is just X11. The info you dumped tells you what the SDL
graphics routines have to work with. If you use OpenGL, then you get to
use all the neat things on your video card. Try running glxinfo to find
out what you really have available. If that doesn't show all you video
card goodies then you don't have your video card properly configured.

		Bob Pendleton

> 
> Also, I have a Logitech Wingman Extreme gamepad currently plugged into a 
> USB port on my PC, so I thought SDL would recognize that but it doesn't. 
> I see it recognized during my kernel boot-up messages, and last time I 
> checked it worked fine when I was running SNES9x. Again I find it 
> strange that nothing was detected.
> 
> Thanks in advance to any insight to this matter.
-- 
+--------------------------------------+
+ Bob Pendleton: writer and programmer +
+ email: Bob at Pendleton.com             +
+ blog:  www.Stonewolf.net             +
+ web:   www.GameProgrammer.com        +
+--------------------------------------+