// Includes

#include <windows.h>
#include <gl/gl.h>

// Function Declarations

LRESULT CALLBACK 
WndProc( HWND hWnd, UINT message,
WPARAM wParam, LPARAM lParam );
VOID EnableOpenGL( HWND hWnd, HDC * hDC, HGLRC * hRC );
VOID DisableOpenGL( HWND hWnd, HDC hDC, HGLRC hRC );

// WinMain

int WINAPI 
WinMain( HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int iCmdShow )
{
WNDCLASS wc;
HWND hWnd;
HDC hDC;
HGLRC hRC;
MSG msg;
BOOL bQuit = FALSE;
float theta = 0.0f;

// register window class
wc.style = CS_OWNDC;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon( NULL, IDI_APPLICATION );
wc.hCursor = LoadCursor( NULL, IDC_ARROW );
wc.hbrBackground = (HBRUSH)GetStockObject( BLACK_BRUSH );
wc.lpszMenuName = NULL;
wc.lpszClassName = "GLSample";
RegisterClass( &wc );

// create main window
hWnd = CreateWindow( 
"GLSample", "OpenGL Sample", 
WS_CAPTION | WS_POPUPWINDOW | WS_VISIBLE,
0, 0, 256, 256,
NULL, NULL, hInstance, NULL );

// enable OpenGL for the window
EnableOpenGL( hWnd, &hDC, &hRC );

// program main loop
while ( !bQuit ) {

// check for messages
if ( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) ) {

// handle or dispatch messages
if ( msg.message == WM_QUIT ) {
bQuit = TRUE;
} else {
TranslateMessage( &msg );
DispatchMessage( &msg );
}

} else {

// OpenGL animation code goes here



}

}

// shutdown OpenGL
DisableOpenGL( hWnd, hDC, hRC );

// destroy the window explicitly
DestroyWindow( hWnd );

return msg.wParam;

}

// Window Procedure

LRESULT CALLBACK 
WndProc( HWND hWnd, UINT message,
WPARAM wParam, LPARAM lParam )
{

switch ( message ) {

case WM_CREATE:
return 0;

case WM_CLOSE:
PostQuitMessage( 0 );
return 0;

case WM_DESTROY:
return 0;

case WM_KEYDOWN:
switch ( wParam ) {

case VK_ESCAPE:
PostQuitMessage( 0 );
return 0;

}
return 0;

default:
return DefWindowProc( hWnd, 
message, wParam, lParam );

}

}

// Enable OpenGL

VOID EnableOpenGL( HWND hWnd, HDC * hDC, HGLRC * hRC )
{
PIXELFORMATDESCRIPTOR pfd;
int iFormat;

// get the device context (DC)
*hDC = GetDC( hWnd );

// set the pixel format for the DC
ZeroMemory( &pfd, sizeof( pfd ) );
pfd.nSize = sizeof( pfd );
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW | 
PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 24;
pfd.cDepthBits = 16;
pfd.iLayerType = PFD_MAIN_PLANE;
iFormat = ChoosePixelFormat( *hDC, &pfd );
SetPixelFormat( *hDC, iFormat, &pfd );

// create and enable the render context (RC)
*hRC = wglCreateContext( *hDC );
wglMakeCurrent( *hDC, *hRC );

}

// Disable OpenGL

VOID DisableOpenGL( HWND hWnd, HDC hDC, HGLRC hRC )
{
wglMakeCurrent( NULL, NULL );
wglDeleteContext( hRC );
ReleaseDC( hWnd, hDC );
}