OpenGL Hook + CS 1.6 WallHack

#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;
}