Blitz3D Function Pointers (Hack)

This code has been declared by its author to be Public Domain code.

Blitz3D Function Pointers (Hack) by RoyFerriby (Posted 21 years ago)
Admittedly, this is a shoddy work around but it does work and stable (apparently)!! This info is aimed at those who prefer to write their own userlibs DLLs in C++ and would like the option of having the DLL call functions in the Blitz3D executable. Forgive any spelling mistakes, I've just returned home from a 14 hour shift!!!
*** The DLL part... // a function pointer declaration for calling Blitz3D code void (__stdcall ABlitz3DFunction)(void); // standard DLL function declaration for Blitz3D userlibs MYDLLNAME_API void BBCALL SetBlitz3DFunction(void) { UINT stackpos,adrs; UINT FAR func; __asm { mov stackpos,esp mov esp,ebp add esp,4 pop adrs mov esp,stackpos } func=(UINT FAR )&ABlitz3DFunction; func=adrs; } // extra DLL function for test purposes only - your DLL would call ABlitz3DFunction() directly! MYDLLNAME_API void BBCALL CallBlitz3DFunction(void) { ABlitz3DFunction(); } * The user libs part (decls file) .... .lib "mydllname.dll" SetBlitz3DFunction():"_SetBlitz3DFunction@0" CallBlitz3DFunction():"_CallBlitz3DFunction@0" * Blitz3D part.... ;* set function test Global SETUP_FUNCS%=1 Gosub test_function SETUP_FUNCS=0 CallBlitz3DFunction() ;<-- testing DLL access only WaitKey End .test_function: SetBlitz3DFunction() If SETUP_FUNCS=0 ; * function body goes here!!! Print "This works!!!!" EndIf Return * that's it folks! your DLL will call any code setup like this correctly and without problems even with the * blitz debugger running and you CAN place Stop commands and step through your Blitz3D function as normal. Anyway, I hope this is of help to someone. If anyone has a better way of doing this, then please let me know. Cheers :)

Blitz3D Function Pointers (Hack) by RoyFerriby

(Posted 21 years ago)

Admittedly, this is a shoddy work around but it does work and stable (apparently)!! This info is aimed at those who prefer to write their own userlibs DLLs in C++ and would like the option of having the DLL call functions in the Blitz3D executable. Forgive any spelling mistakes, I've just returned home from a 14 hour shift!!!

*** The DLL part...

// a function pointer declaration for calling Blitz3D code
void (__stdcall *ABlitz3DFunction)(void);

// standard DLL function declaration for Blitz3D userlibs
MYDLLNAME_API void BBCALL SetBlitz3DFunction(void)
{
    UINT stackpos,adrs;
    UINT FAR *func;
    __asm
    {
        mov stackpos,esp
        mov esp,ebp
        add esp,4
        pop adrs
        mov esp,stackpos
     }
     func=(UINT FAR *)&ABlitz3DFunction;
    *func=adrs;
}

// extra DLL function for test purposes only - your DLL would call ABlitz3DFunction() directly!
MYDLLNAME_API void BBCALL CallBlitz3DFunction(void)
{
    ABlitz3DFunction();
}

*** The user libs part  (decls file) ....

.lib "mydllname.dll"

SetBlitz3DFunction():"_SetBlitz3DFunction@0"
CallBlitz3DFunction():"_CallBlitz3DFunction@0"

*** Blitz3D part....

;*** set function test

Global SETUP_FUNCS%=1
Gosub test_function
SETUP_FUNCS=0

CallBlitz3DFunction()     ;<-- testing DLL access only

WaitKey
End

.test_function:
                SetBlitz3DFunction()
If SETUP_FUNCS=0
	; *** function body goes here!!!
	Print "This works!!!!"
EndIf
	Return

*** that's it folks!  your DLL will call any code setup like this correctly and without problems even with the
*** blitz debugger running and you CAN place Stop commands and step through your Blitz3D function as normal.

Anyway, I hope this is of help to someone.
If anyone has a better way of doing this,  then please let me know.  Cheers :)