#pragma comment (lib,"opengl32.lib")
#pragma comment (lib,"glu32.lib")


#include <windows.h>

#include <gl\gl.h>

#include <gl\glu.h>

#define WIN_WID 600

#define WIN_HEI 600

HDC		hdc;
HGLRC	hrc;

char CN[] = "X";
void RenderScene();
void Enable (HWND hwnd,HDC * hdc,HGLRC * hrc);
void Disable (HWND hwnd,HDC hdc,HGLRC hrc);
void ResizeOpenGLScene(int width, int height);

LRESULT CALLBACK WndProc (HWND hwnd,UINT msg,WPARAM wparam,LPARAM lparam);

int WINAPI WinMain (HINSTANCE hi,HINSTANCE hp,LPSTR Cl,int Sc)
{

	WNDCLASS wc;
	MSG		 msg;
	HWND	 hwnd;

	wc.cbClsExtra = 0;
	wc.cbWndExtra = 0;
	wc.hbrBackground = (HBRUSH) GetStockObject (4);
    wc.hCursor = LoadCursor (NULL,IDC_ARROW);
	wc.hIcon = LoadIcon (NULL,IDI_APPLICATION);
	wc.hInstance = hi;
	wc.lpfnWndProc = WndProc;
	wc.lpszClassName = CN;
	wc.lpszMenuName = NULL;
	wc.style = CS_OWNDC | CS_VREDRAW | CS_HREDRAW;

	if (!RegisterClass (&wc))
	{
		MessageBox (hwnd,"Error registering class","Error # 1",MB_OK|MB_ICONEXCLAMATION);
		return 0;
	}

	hwnd = CreateWindow (CN,"Texture Test",WS_CAPTION,50,50,WIN_WID,WIN_HEI,NULL,NULL,hi,NULL);

	ShowWindow (hwnd,SW_NORMAL);
	UpdateWindow (hwnd);
	Enable (hwnd,&hdc,&hrc);
	ResizeOpenGLScene (WIN_WID,WIN_HEI);
			
	while (1)
	{
		if (PeekMessage (&msg,hwnd,0,0,PM_REMOVE))
		{
			if (msg.wParam == VK_ESCAPE)
				break;

			TranslateMessage (&msg);
			DispatchMessage (&msg);
		}
		else
		{
			RenderScene();
		}
	}

	Disable (hwnd,hdc,hrc);
	return 0;

}

LRESULT CALLBACK WndProc (HWND hwnd,UINT msg,WPARAM wparam,LPARAM lparam)
{

	switch (msg)
	{
	case WM_CLOSE:
		DestroyWindow (hwnd);
		break;
	case WM_DESTROY:
		PostQuitMessage (0);
		break;
	default:
		break;
	}
	
	return DefWindowProc (hwnd,msg,wparam,lparam);
}


void RenderScene ()
{
	 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	
	 glLoadIdentity();

	  glBegin (GL_QUADS);
		glVertex2f (0.5,0.5);
		glVertex2f (0.5,-0.5);
		glVertex2f (-0.5,-0.5);
		glVertex2f (-0.5,0.5);
	glEnd();

	SwapBuffers (hdc);
}

void ResizeOpenGLScene(int width, int height)
{  
	if (height == 0) 
	{    height = 1;   
	}  
	
	glViewport(0,0, width, height);		

	glMatrixMode(GL_PROJECTION);					
	glLoadIdentity();					

	gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f, 100.0f);  

	glMatrixMode(GL_MODELVIEW);					
	glLoadIdentity();						
}

void Enable (HWND hwnd,HDC * hdc,HGLRC * hrc)
{
	int FORMAT;					 
	PIXELFORMATDESCRIPTOR PFD;   

	* hdc = GetDC (hwnd);        

	PFD.cColorBits = 24;
	PFD.cDepthBits = 16;
	PFD.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
	PFD.iPixelType = PFD_TYPE_RGBA;
	PFD.nSize = sizeof (PFD);
	PFD.nVersion = 1;

	FORMAT = ChoosePixelFormat (* hdc,&PFD);
	SetPixelFormat (* hdc,FORMAT,&PFD);

	* hrc = wglCreateContext (* hdc);
	wglMakeCurrent (* hdc,* hrc); 

}
 
void Disable (HWND hwnd,HDC hdc,HGLRC hrc)
{
	wglMakeCurrent (NULL,NULL);
	wglDeleteContext (hrc);
	ReleaseDC (hwnd,hdc);
}