Although the 3dfxvgl.dll driver file will be in the windows \ system directory
on 9X if a Voodoo 1, 2 or Rush is present and the current drivers have been installed
(using e.g. GLSetup, see the external links section), simply checking for the presence
of the driver dll does not guarantee that 3dfx hardware is there, since it might have been
removed after driver installation.  

Also, if you dynamically load 3dfxvgl.dll using LoadLibrary (or load it implicitly by 
runnning code linked to 3dfxvgl.lib, see the downloads section) and the hardware is 
not present, 3dfxvgl.dll will fault at runtime when DLL_THREAD_PROCESS_ATTACH is
called during the dll load and Glide is initialised but cannot find any 3dfx hardware.

The function below dynamically loads the glide2x dll, imports the grSstQueryBoards function
(which can be called without initialising Glide) and uses it to determine whether any 3dfx cards
are actually present in the machine. The function ought to be futureproof as long as glide2x.dll is contained in future 3dfx 
driver distributions as well as Glide 3 or later version dlls, and should be fairly easy to modify
if glide2x.dll is replaced.

------------------------------------------------------------------------------------------------

// prototypes for dynamic link
#include "glide.h"

BOOL (__stdcall* GLIDEFUN_grSstQueryBoards) (GrHwConfiguration* hwconfig);

bool GlideReports3dfxBoardPresent(void)
{
	char GlideDriver[] = "glide2x.dll";

	// load glide
	HMODULE hmGlide = LoadLibrary(GlideDriver);

	if (hmGlide)
		{
		// get query function
		GLIDEFUN_grSstQueryBoards = (BOOL (__stdcall*)(GrHwConfiguration* hwconfig)) GetProcAddress(hmGlide, "_grSstQueryBoards@4");

		if (GLIDEFUN_grSstQueryBoards)
			{
			GrHwConfiguration GlideHwConfig;

			GLIDEFUN_grSstQueryBoards(&GlideHwConfig);

			if (GlideHwConfig.num_sst > 0)
				{
				FreeLibrary(hmGlide);
				return true;
				}
			else
				{
				FreeLibrary(hmGlide);
				return false;
				}
			}
		else
			{
			FreeLibrary(hmGlide);
			return false;
			}
		}
	else
		{
		return false;
		}
}

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Checking for the presence of 3dfx hardware, however, is not enough to guarantee that 
3dfxvgl.dll (if present) will work properly.  Consider the case of a machine which 
begins life with a Voodoo 1 and some generic 2d card onboard, and a copy of the 
3dfxvgl.dll standalone driver (correctly) installed by GLSetup, but for which the 
Voodoo 1 and 2d card are then removed and replaced with a 3dfx Banshee and GLSetup 
run again.

In this case 3dfxvgl.dll will be present in the windows \ system directory, and 3dfx hardware
is installed, but 3dfxvgl.dll is not an appropriate choice for runtime rendering (it should not 
fault on startup, but will not render correctly; the Banshee ICD driver should be loaded through
the Microsoft opengl32.dll instead).

The function below attempts to identify the precise type of any 3dfx cards present and 
determine whether any of them are "standalone" (Voodoo 1, 2 or Rush) types, using Glide2x.
Like the "GlideReports3dfxBoardPresent" function above, it works by dynamically loading Glide,
and should be safe to run even if glide is not installed, or no 3dfx hardware is present.

I would be grateful for comments as to whether this function actually works and correctly 
identifies different varieties of 3dfx board as "standalone" (Voodoo 1, 2 or Rush) or
"ICD" (Banshee, Voodoo 3, or later), sent to the mailing address on the front page of the site.
I have done some testing, but obviously not on every possible type of OEM manufactured 3dfx
card.  If it fails, it would be interesting to know the exact type of 3dfx card involved
(including OEM manufacturer), the type reported in the GrHwConfiguration structure, and 
the numerical value of the fbiRev value (if any).

------------------------------------------------------------------------------------------------

// Glide stuff
// prototype for dynamic link
#include "glide.h"

BOOL (__stdcall* GLIDEFUN_grSstQueryBoards) (GrHwConfiguration* hwconfig);
void (__stdcall* GLIDEFUN_grGlideInit) (void);
void (__stdcall* GLIDEFUN_grGlideShutdown) (void);
BOOL (__stdcall* GLIDEFUN_grSstQueryHardware) (GrHwConfiguration* hwconfig);

static bool GlideReports3dfxStandaloneBoardPresent(void)
{
	char GlideDriver[] = "glide2x.dll";

	// load glide
	HMODULE hmGlide = LoadLibrary(GlideDriver);

	if (hmGlide)
		{
		// Glide2x driver dll found

		// get functions
		GLIDEFUN_grSstQueryBoards = (BOOL (__stdcall*)(GrHwConfiguration* hwconfig)) GetProcAddress(hmGlide, "_grSstQueryBoards@4");
		GLIDEFUN_grGlideInit = (void (__stdcall*)(void)) GetProcAddress(hmGlide, "_grGlideInit@0");
		GLIDEFUN_grGlideShutdown = (void (__stdcall*)(void)) GetProcAddress(hmGlide, "_grGlideShutdown@0");
		GLIDEFUN_grSstQueryHardware = (BOOL (__stdcall*)(GrHwConfiguration* hwconfig)) GetProcAddress(hmGlide, "_grSstQueryHardware@4");

		if ((GLIDEFUN_grSstQueryBoards) &&
			(GLIDEFUN_grGlideInit) &&
			(GLIDEFUN_grGlideShutdown) &&
			(GLIDEFUN_grSstQueryHardware))
			{
			GrHwConfiguration GlideHwConfig;

			GLIDEFUN_grSstQueryBoards(&GlideHwConfig);

			if (GlideHwConfig.num_sst > 0)
				{
				// hardware present; we can initialise Glide
				GLIDEFUN_grGlideInit();

				// fill out hardware structure properly
				GLIDEFUN_grSstQueryHardware(&GlideHwConfig);

				// search for a Voodoo 1, Rush or 2 (standalone) type
				// in data for all boards found
				bool StandaloneCardPresent = false;

				for (int i=0; ((i<GlideHwConfig.num_sst) && (!StandaloneCardPresent)); i++)
					{
					GrSstType type = (GlideHwConfig.SSTs[i]).type;
					int fbiRev = 0;

					switch(type)
						{
						case GR_SSTTYPE_VOODOO:
							fbiRev = (((GlideHwConfig.SSTs[i]).sstBoard).VoodooConfig).fbiRev;
							break;

						case GR_SSTTYPE_Voodoo2:
							fbiRev = (((GlideHwConfig.SSTs[i]).sstBoard).Voodoo2Config).fbiRev;
							break;

						case GR_SSTTYPE_SST96:
						case GR_SSTTYPE_AT3D:
						default:
							break;
						}

					if ((type == GR_SSTTYPE_VOODOO) || // Voodoo / Banshee / Voodoo 3?
						(type == GR_SSTTYPE_Voodoo2)) // Voodoo 2
						{
						if (fbiRev < 0x1000) // Banshee / Voodoo 3 has fbiRev > 0x1000
							{
							// standalone card type Voodoo 1 / 2
							StandaloneCardPresent = true;
							}
						}
					else if (type == GR_SSTTYPE_SST96) // Voodoo Rush
					 	{
					 	// standalone card type Voodoo Rush
					 	StandaloneCardPresent = true;
					 	}
					}

				// shut down glide
				GLIDEFUN_grGlideShutdown();

				FreeLibrary(hmGlide);
				return StandaloneCardPresent;
				}
			else
				{
				FreeLibrary(hmGlide);
				return false;
				}
			}
		else
			{
			FreeLibrary(hmGlide);
			return false;
			}
		}
	else
		{
		return false;
		}
}

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