MAXScript plug-in extensions are packaged as Win32 DLL's in almost exactly the same way as standard MAX plug-ins. They are named with a specific suffix to fit in with the MAX plug-in naming scheme (.DLX) and should be installed in one of the MAX plug-in directories. MAXScript looks for and loads all the *.DLX files it finds in the MAX plug-in directories.
You should be familiar with the section on MAX plug-in construction in the MAX SDK documentation because the following notes primarily describe what is different about setting up MAXScript plug-ins.
The plug-in's external interface is defined with a .DEF file, as are MAX plug-ins, but in this case there are only three entry points:
LIBRARY <plugin_name>
EXPORTS
LibDescription @1
LibInit @2
LibVersion @3
SECTIONS
.data READ WRITE
The LibDescription and LibVersion entry points are the same as for MAX plug-ins. The LibInit entry is called by MAX after MAXScript has loaded itself and all its .DLX plug-ins so that each can perform any runtime initialization. MAXScript is fully functional at the time these init functions are called.
The following code shows a typical DLX entry point implementation (this is from sample.cpp in the SDK). All of the required headers are included by the master header file, MAXscrpt.h, including Max.h for MAX SDK-related code.
#include "MAXScrpt.h"
HMODULE hInstance;
BOOL APIENTRY
DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved)
{
static BOOL controlsInit = FALSE;
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
// Hang on to this DLL's instance handle.
hInstance = hModule;
if (!controlsInit)
{
controlsInit = TRUE;
// Initialize Win95 controls
InitCommonControls();
}
break;
}
return(TRUE);
}
__declspec( dllexport ) void
LibInit()
{
// do any setup here. MAXScript is fully up at this point.
}
__declspec( dllexport ) const TCHAR *
LibDescription()
{
return _T("Sample MAXscript DLX");
}
__declspec( dllexport ) ULONG
LibVersion()
{
return VERSION_3DSMAX;
}
If any Win32 common controls or MAX custom controls are to be used in the DLL, you should initialize them during process attach, in the same way you would in a MAX DLL. For the LibVersion entry point, you should return the current 3DSMAX version as shown.