OpenGL CS 1.6 Wallhack (C++)

#pragma comment(lib,"OpenGL32.lib")
#pragma comment(lib,"GLu32.lib")

#include <windows.h>
#include <string>
#include <tlhelp32.h>
#include <iostream>
#include <gl\gl.h>
#include <gl\glu.h>

typedef void ( APIENTRY *glBegin_t )( GLenum );
typedef void ( APIENTRY *glEnd_t )( void );
typedef void ( APIENTRY *glClear_t )( GLbitfield );
typedef void ( APIENTRY *glVertex3fv_t )( const GLfloat *v );
typedef void ( APIENTRY *glVertex3f_t )( GLfloat x,  GLfloat y,  GLfloat z );
typedef void ( APIENTRY *glEnable_t )( GLenum );

glBegin_t pglBegin = NULL;
glEnd_t pglEnd = NULL;
glClear_t pglClear = NULL;
glVertex3fv_t pglVertex3fv = NULL;
glVertex3f_t pglVertex3f = NULL;
glEnable_t pglEnable = NULL;

bool wallhack = false;

void DrawBox(GLfloat x, GLfloat y, GLfloat z, GLfloat width, GLfloat height) 
{ 
glBegin(GL_QUADS); 
glVertex3f(x,y,z); 
glVertex3f(x+width,y,z); 
glVertex3f(x+width,y+height,z); 
glVertex3f(x,y+height,z); 
glEnd(); 
} 


//=================================================================================
// ###################### Hooked OpenGL Functions #################################
//=================================================================================

void APIENTRY Hooked_glBegin( GLenum mode )
{
	if (GetAsyncKeyState(VK_F1)&1) wallhack = !wallhack;

	if (wallhack)
	{
		if(mode == GL_TRIANGLES || mode == GL_TRIANGLE_STRIP || mode == GL_TRIANGLE_FAN)
			glDepthRange(0, 0.5);
		else
			glDepthRange(0.5, 1);
	}

	if(pglBegin)
		(*pglBegin)(mode);
}

void APIENTRY Hooked_glEnd( void )
{
	(*pglEnd)();
}

void APIENTRY Hooked_glVertex3fv( GLfloat *v )
{	
	(*pglVertex3fv)( v );
}


void APIENTRY Hooked_glVertex3f ( GLfloat x,  GLfloat y,  GLfloat z )
{
	(*pglVertex3f)( x, y, z );
}

void APIENTRY Hooked_glClear( GLbitfield mask )
{
	(*pglClear)( mask );
}

void APIENTRY Hooked_glEnable (GLenum cap)
{
		/*if (GetAsyncKeyState(VK_F2))
			DrawBox(200,100,0,50,30);*/

	(*pglEnable)(cap);
}

void *DetourFunc( BYTE *src, const BYTE *dst, const int len )
{
	BYTE *jmp = (BYTE*)malloc( len + 5 );
	DWORD dwback;
	VirtualProtect( src, len, PAGE_READWRITE, &dwback );
	memcpy( jmp, src, len );
	jmp += len;
	jmp[0] = 0xE9;
	*(DWORD*)( jmp + 1 ) = (DWORD)( src + len - jmp ) - 5;
	src[0] = 0xE9;
	*(DWORD*)( src + 1 ) = (DWORD)( dst - src ) - 5;
	VirtualProtect( src, len, dwback, &dwback );
	return ( jmp - len );
}
void HookGL()
{
	HMODULE hOpenGL = GetModuleHandle("opengl32.dll");
	pglVertex3fv =   (glVertex3fv_t)DetourFunc( (LPBYTE)GetProcAddress(hOpenGL, "glVertex3fv" ), (LPBYTE)&Hooked_glVertex3fv, 6 );
	pglVertex3f  =   (glVertex3f_t)DetourFunc( (LPBYTE)GetProcAddress(hOpenGL, "glVertex3f" ), (LPBYTE)&Hooked_glVertex3f, 6);
	pglBegin     =   (glBegin_t)DetourFunc( (LPBYTE)GetProcAddress(hOpenGL, "glBegin"),(LPBYTE)&Hooked_glBegin,6);
	pglEnd       =   (glEnd_t)DetourFunc( (LPBYTE)GetProcAddress(hOpenGL, "glEnd" ), (LPBYTE)&Hooked_glEnd, 6 );
	pglClear     =   (glClear_t)DetourFunc( (LPBYTE)GetProcAddress(hOpenGL, "glClear" ), (LPBYTE)&Hooked_glClear, 7 );
	pglEnable    =   (glEnable_t)DetourFunc( (LPBYTE)GetProcAddress(hOpenGL, "glEnable"), (LPBYTE)&Hooked_glEnable, 6);
}
	

DWORD WINAPI dwMainThread( LPVOID )
{	
	HookGL();

	return TRUE;
}

BOOL WINAPI DllMain( HINSTANCE hInstDLL,DWORD dwReason,LPVOID lpReserved )
{
	if( dwReason==DLL_PROCESS_ATTACH )
		CreateThread(0,0,dwMainThread,0,0,0);

return TRUE;
}