Thread: OpenGL Hooking

OK, Ive been having some problems trying to hook an OpenGL table within a process only to recieve crashing. I believe its due to my cast conversions and such, but I am clueless on how to fix it.

Code:

glViewport_t	 pglViewport;

//OpenGL function to hook
void APIENTRY hooked_glViewport( GLint x, GLint y, GLsizei width, GLsizei height )
{
	return pglViewport( x, y, width, height );
}


//Keeps crashing here
void CodeWalk( DWORD dwStartAddress, DWORD dwEndAddress )
{
	for ( DWORD dwCurrentAddress = dwStartAddress; dwCurrentAddress <= dwEndAddress-0x6; dwCurrentAddress+=0x6 )
	{


		PDWORD pdwTempAddress = ( PDWORD ) dwCurrentAddress + 0x2;

		PDWORD pdwTableAddress = ( PDWORD ) *pdwTempAddress;

		HMODULE hmOpenGL = LoadLibrary( "opengl32.dll" );

		if ( *pdwTableAddress == ( DWORD ) GetProcAddress( hmOpenGL, "glViewport" ) )
		{
			pglViewport = ( glViewport_t ) *pdwTableAddress;
			*pdwTableAddress = ( DWORD ) &hooked_glViewport;
		}
	}

}
//Hooked with CreateThread after sleeping for 2 seconds
void SetupOpenGLHooks( void )
{
	DWORD dwImportCode = (DWORD)0x01D7AFA0;

	if(dwImportCode != NULL)
	{
	CodeWalk(dwImportCode,dwImportCode + 0x870); //Lets go through the table
	}
	else
	{
		MessageBox(NULL,"Couldnt Find the TLS","newhook",NULL);
	}

}

And just why are you hooking a DLL in this fashion?

Originally Posted by Bubba

And just why are you hooking a DLL in this fashion?

Generally, hooking a OpenGL program, is basicaly how hackers get all the cool stuff on the screen for hacks. I'm not accusing anyone tho.

Code:

//Keeps crashing here
void CodeWalk( DWORD dwStartAddress, DWORD dwEndAddress )
{
	for ( DWORD dwCurrentAddress = dwStartAddress; dwCurrentAddress <= dwEndAddress-0x6; dwCurrentAddress+=0x6 )
	{


		PDWORD pdwTempAddress = ( PDWORD ) dwCurrentAddress + 0x2;

		PDWORD pdwTableAddress = ( PDWORD ) *pdwTempAddress;

		HMODULE hmOpenGL = LoadLibrary( "opengl32.dll" );

		if ( *pdwTableAddress == ( DWORD ) GetProcAddress( hmOpenGL, "glViewport" ) )
		{
			pglViewport = ( glViewport_t ) *pdwTableAddress;
			*pdwTableAddress = ( DWORD ) &hooked_glViewport;
		}
	}

}

Suspicious at best.

This isn't a hacking forum.