/* main.cpp */

/* NeHe lesson 1 code.  Only modifications are in DrawGLScene and main */

#include <windows.h>								// Header File For Windows

#include <gl\gl.h>								// Header File For The OpenGL32 Library

#include <gl\glu.h>								// Header File For The GLu32 Library

#include <gl\glaux.h>								// Header File For The GLaux Library

#include "Scene.h"

HGLRC		hRC=NULL;							// Permanent Rendering Context

HDC		hDC=NULL;							// Private GDI Device Context

HWND		hWnd=NULL;							// Holds Our Window Handle

HINSTANCE	hInstance;							// Holds The Instance Of The Application


bool	keys[256];								// Array Used For The Keyboard Routine

bool	active=TRUE;								// Window Active Flag Set To TRUE By Default

bool	fullscreen=TRUE;							// Fullscreen Flag Set To Fullscreen Mode By Default


Scene* scene;

LRESULT	CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);				// Declaration For WndProc


GLvoid ReSizeGLScene(GLsizei width, GLsizei height)				// Resize And Initialize The GL Window

{
	if (height==0)								// Prevent A Divide By Zero By

	{
		height=1;							// Making Height Equal One

	}

	glViewport(0, 0, width, height);					// Reset The Current Viewport


	glMatrixMode(GL_PROJECTION);						// Select The Projection Matrix

	glLoadIdentity();							// Reset The Projection Matrix


	// Calculate The Aspect Ratio Of The Window

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

	glMatrixMode(GL_MODELVIEW);						// Select The Modelview Matrix

	glLoadIdentity();							// Reset The Modelview Matrix

}

int InitGL(GLvoid)								// All Setup For OpenGL Goes Here

{

	glShadeModel(GL_SMOOTH);						// Enables Smooth Shading


	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);					// Black Background


	glClearDepth(1.0f);							// Depth Buffer Setup

	glEnable(GL_DEPTH_TEST);						// Enables Depth Testing

	glDepthFunc(GL_LEQUAL);							// The Type Of Depth Test To Do


	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);			// Really Nice Perspective Calculations


	return TRUE;								// Initialization Went OK

}

int DrawGLScene(GLvoid)								// Here's Where We Do All The Drawing

{
	scene->render();
}

GLvoid KillGLWindow(GLvoid)							// Properly Kill The Window

{

	if (fullscreen)								// Are We In Fullscreen Mode?

	{

		ChangeDisplaySettings(NULL,0);					// If So Switch Back To The Desktop

		ShowCursor(TRUE);						// Show Mouse Pointer

	}

	if (hRC)								// Do We Have A Rendering Context?

	{

		if (!wglMakeCurrent(NULL,NULL))					// Are We Able To Release The DC And RC Contexts?

		{

			MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}

		if (!wglDeleteContext(hRC))					// Are We Able To Delete The RC?

		{

			MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}
		hRC=NULL;							// Set RC To NULL

	}

	if (hDC && !ReleaseDC(hWnd,hDC))					// Are We Able To Release The DC

	{
		MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hDC=NULL;							// Set DC To NULL

	}

	if (hWnd && !DestroyWindow(hWnd))					// Are We Able To Destroy The Window?

	{
		MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hWnd=NULL;							// Set hWnd To NULL

	}

	if (!UnregisterClass("OpenGL",hInstance))			// Are We Able To Unregister Class

	{
		MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hInstance=NULL;									// Set hInstance To NULL

	}
}

BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag)
{

	GLuint		PixelFormat;						// Holds The Results After Searching For A Match


	WNDCLASS	wc;							// Windows Class Structure


	DWORD		dwExStyle;						// Window Extended Style

	DWORD		dwStyle;						// Window Style


	RECT WindowRect;							// Grabs Rectangle Upper Left / Lower Right Values

	WindowRect.left=(long)0;						// Set Left Value To 0

	WindowRect.right=(long)width;						// Set Right Value To Requested Width

	WindowRect.top=(long)0;							// Set Top Value To 0

	WindowRect.bottom=(long)height;						// Set Bottom Value To Requested Height


	fullscreen=fullscreenflag;						// Set The Global Fullscreen Flag


	hInstance		= GetModuleHandle(NULL);			// Grab An Instance For Our Window

	wc.style		= CS_HREDRAW | CS_VREDRAW | CS_OWNDC;		// Redraw On Move, And Own DC For Window

	wc.lpfnWndProc		= (WNDPROC) WndProc;				// WndProc Handles Messages

	wc.cbClsExtra		= 0;						// No Extra Window Data

	wc.cbWndExtra		= 0;						// No Extra Window Data

	wc.hInstance		= hInstance;					// Set The Instance

	wc.hIcon		= LoadIcon(NULL, IDI_WINLOGO);			// Load The Default Icon

	wc.hCursor		= LoadCursor(NULL, IDC_ARROW);			// Load The Arrow Pointer

	wc.hbrBackground	= NULL;						// No Background Required For GL

	wc.lpszMenuName		= NULL;						// We Don't Want A Menu

	wc.lpszClassName	= "OpenGL";					// Set The Class Name


	if (!RegisterClass(&wc))						// Attempt To Register The Window Class

	{
		MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;							// Exit And Return FALSE

	}

	if (fullscreen)								// Attempt Fullscreen Mode?

	{

		DEVMODE dmScreenSettings;					// Device Mode

		memset(&dmScreenSettings,0,sizeof(dmScreenSettings));		// Makes Sure Memory's Cleared

		dmScreenSettings.dmSize=sizeof(dmScreenSettings);		// Size Of The Devmode Structure

		dmScreenSettings.dmPelsWidth	= width;			// Selected Screen Width

		dmScreenSettings.dmPelsHeight	= height;			// Selected Screen Height

		dmScreenSettings.dmBitsPerPel	= bits;				// Selected Bits Per Pixel

		dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

		// Try To Set Selected Mode And Get Results.  NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.

		if (ChangeDisplaySettings(&dmScreenSettings,0)!=DISP_CHANGE_SUCCESSFUL)
		{

			// If The Mode Fails, Offer Two Options.  Quit Or Run In A Window.

			if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
			{

				fullscreen=FALSE;				// Select Windowed Mode (Fullscreen=FALSE)

			}
			else
			{

				// Pop Up A Message Box Letting User Know The Program Is Closing.

				MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);
				return FALSE;					// Exit And Return FALSE

			}
		}
	}

	if (fullscreen)								// Are We Still In Fullscreen Mode?

	{

		dwExStyle=WS_EX_APPWINDOW;					// Window Extended Style

		dwStyle=WS_POPUP;						// Windows Style

		ShowCursor(FALSE);						// Hide Mouse Pointer

	}
	else
	{

		dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;			// Window Extended Style

		dwStyle=WS_OVERLAPPEDWINDOW;					// Windows Style

	}

	AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle);		// Adjust Window To True Requested Size


	if (!(hWnd=CreateWindowEx(	dwExStyle,				// Extended Style For The Window

					"OpenGL",				// Class Name

					title,					// Window Title

					WS_CLIPSIBLINGS |			// Required Window Style

					WS_CLIPCHILDREN |			// Required Window Style

					dwStyle,				// Selected Window Style

					0, 0,					// Window Position

					WindowRect.right-WindowRect.left,	// Calculate Adjusted Window Width

					WindowRect.bottom-WindowRect.top,	// Calculate Adjusted Window Height

					NULL,					// No Parent Window

					NULL,					// No Menu

					hInstance,				// Instance

					NULL)))					// Don't Pass Anything To WM_CREATE


	{
		KillGLWindow();							// Reset The Display

		MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;							// Return FALSE

	}

	static	PIXELFORMATDESCRIPTOR pfd=					// pfd Tells Windows How We Want Things To Be

	{
		sizeof(PIXELFORMATDESCRIPTOR),					// Size Of This Pixel Format Descriptor

		1,								// Version Number

		PFD_DRAW_TO_WINDOW |						// Format Must Support Window

		PFD_SUPPORT_OPENGL |						// Format Must Support OpenGL

		PFD_DOUBLEBUFFER,						// Must Support Double Buffering

		PFD_TYPE_RGBA,							// Request An RGBA Format

		bits,								// Select Our Color Depth

		0, 0, 0, 0, 0, 0,						// Color Bits Ignored

		0,								// No Alpha Buffer

		0,								// Shift Bit Ignored

		0,								// No Accumulation Buffer

		0, 0, 0, 0,							// Accumulation Bits Ignored

		16,								// 16Bit Z-Buffer (Depth Buffer)

		0,								// No Stencil Buffer

		0,								// No Auxiliary Buffer

		PFD_MAIN_PLANE,							// Main Drawing Layer

		0,								// Reserved

		0, 0, 0								// Layer Masks Ignored

	};

	if (!(hDC=GetDC(hWnd)))							// Did We Get A Device Context?

	{
		KillGLWindow();							// Reset The Display

		MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;							// Return FALSE

	}

	if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd)))				// Did Windows Find A Matching Pixel Format?

	{
		KillGLWindow();							// Reset The Display

		MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;							// Return FALSE

	}

	if(!SetPixelFormat(hDC,PixelFormat,&pfd))				// Are We Able To Set The Pixel Format?

	{
		KillGLWindow();							// Reset The Display

		MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;							// Return FALSE

	}

	if (!(hRC=wglCreateContext(hDC)))					// Are We Able To Get A Rendering Context?

	{
		KillGLWindow();							// Reset The Display

		MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;							// Return FALSE

	}

	if(!wglMakeCurrent(hDC,hRC))						// Try To Activate The Rendering Context

	{
		KillGLWindow();							// Reset The Display

		MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;							// Return FALSE

	}

	ShowWindow(hWnd,SW_SHOW);						// Show The Window

	SetForegroundWindow(hWnd);						// Slightly Higher Priority

	SetFocus(hWnd);								// Sets Keyboard Focus To The Window

	ReSizeGLScene(width, height);						// Set Up Our Perspective GL Screen


	if (!InitGL())								// Initialize Our Newly Created GL Window

	{
		KillGLWindow();							// Reset The Display

		MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;							// Return FALSE

	}

	return TRUE;								// Success

}

LRESULT CALLBACK WndProc(	HWND	hWnd,					// Handle For This Window

				UINT	uMsg,					// Message For This Window

				WPARAM	wParam,					// Additional Message Information

				LPARAM	lParam)					// Additional Message Information

{

	switch (uMsg)								// Check For Windows Messages

	{

		case WM_ACTIVATE:						// Watch For Window Activate Message

		{
			if (!HIWORD(wParam))					// Check Minimization State

			{
				active=TRUE;					// Program Is Active

			}
			else
			{
				active=FALSE;					// Program Is No Longer Active

			}

			return 0;						// Return To The Message Loop

		}

		case WM_SYSCOMMAND:						// Intercept System Commands

		{
			switch (wParam)						// Check System Calls

			{
				case SC_SCREENSAVE:				// Screensaver Trying To Start?

				case SC_MONITORPOWER:				// Monitor Trying To Enter Powersave?

				return 0;					// Prevent From Happening

			}
			break;							// Exit

		}

		case WM_CLOSE:							// Did We Receive A Close Message?

		{
			PostQuitMessage(0);					// Send A Quit Message

			return 0;						// Jump Back

		}

		case WM_KEYDOWN:						// Is A Key Being Held Down?

		{
			keys[wParam] = TRUE;					// If So, Mark It As TRUE

			return 0;						// Jump Back

		}

		case WM_KEYUP:							// Has A Key Been Released?

		{
			keys[wParam] = FALSE;					// If So, Mark It As FALSE

			return 0;						// Jump Back

		}

		case WM_SIZE:							// Resize The OpenGL Window

		{
			ReSizeGLScene(LOWORD(lParam),HIWORD(lParam));		// LoWord=Width, HiWord=Height

			return 0;						// Jump Back

		}
	}

	// Pass All Unhandled Messages To DefWindowProc

	return DefWindowProc(hWnd,uMsg,wParam,lParam);
}

/*int WINAPI WinMain(	HINSTANCE	hInstance,				// Instance
			HINSTANCE	hPrevInstance,				// Previous Instance
			LPSTR		lpCmdLine,				// Command Line Parameters
			int		nCmdShow)				// Window Show State
{*/
int main(int, char**){

	MSG	msg;								// Windows Message Structure

	BOOL	done=FALSE;							// Bool Variable To Exit Loop


	// Ask The User Which Screen Mode They Prefer

	if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO)
	{
		fullscreen=FALSE;						// Windowed Mode

	}

	// Create Our OpenGL Window

	if (!CreateGLWindow("NeHe's OpenGL Framework",640,480,16,fullscreen))
	{
		return 0;							// Quit If Window Was Not Created

	}

	scene = new Scene();
	scene->begin();

	while(!done)								// Loop That Runs Until done=TRUE

	{

		if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))			// Is There A Message Waiting?

		{

			if (msg.message==WM_QUIT)				// Have We Received A Quit Message?

			{
				done=TRUE;					// If So done=TRUE

			}
			else							// If Not, Deal With Window Messages

			{

				TranslateMessage(&msg);				// Translate The Message

				DispatchMessage(&msg);				// Dispatch The Message

			}
		}
		else								// If There Are No Messages

		{

			// Draw The Scene.  Watch For ESC Key And Quit Messages From DrawGLScene()

			if (active)						// Program Active?

			{
				if (keys[VK_ESCAPE])				// Was ESC Pressed?

				{
					done=TRUE;				// ESC Signalled A Quit

				}
				else						// Not Time To Quit, Update Screen

				{

					DrawGLScene();				// Draw The Scene

					SwapBuffers(hDC);			// Swap Buffers (Double Buffering)

				}
			}

			if (keys[VK_F1])					// Is F1 Being Pressed?

			{
				keys[VK_F1]=FALSE;				// If So Make Key FALSE

				KillGLWindow();					// Kill Our Current Window

				fullscreen=!fullscreen;				// Toggle Fullscreen / Windowed Mode

				// Recreate Our OpenGL Window

				if (!CreateGLWindow("NeHe's OpenGL Framework",640,480,16,fullscreen))
				{
					return 0;				// Quit If Window Was Not Created

				}
			}
		}
	}

	// Shutdown

	KillGLWindow();								// Kill The Window

	return (msg.wParam);							// Exit The Program

}

/* Scene.h */
  
#if !defined(SCENE_HEADER)
	#define SCENE_HEADER

	#if defined(__WIN32__)
		#include <windows.h>
	#endif
	#include <GL/gl.h>

	class Geometry;

	class Scene{
		private:

			GLboolean done;
			Geometry* object;

		public:

			Scene();
			~Scene();
			GLboolean begin();
			GLvoid render();

	};

#endif

/* Scene.cpp */
   
#if !defined(SCENE)
	#define SCENE

	#include "Scene.h"

	#include <ctime>
	#include "Geometry.h"

	Scene::Scene(){
		object = new Geometry();

	}

	Scene::~Scene(){
		delete object;
	}

	GLboolean Scene::begin(){
		glEnable(GL_LIGHTING);
	}

	GLvoid Scene::render(){
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glLoadIdentity();
		object->render();
	}

#endif

/* Geometry.h */
   
#if !defined(GEOMETRY_HEADER)
	#define GEOMETRY_HEADER

	#if defined(__WIN32__)
		#include <windows.h>
	#endif
	#include <GL/gl.h>

	class Geometry{
		public:

			Geometry();
			virtual ~Geometry();
			virtual void render();

	};

#endif

/* Geometry.cpp */
   
#if !defined(GEOMETRY)
	#define GEOMETRY

	#define null 0

	#include "Geometry.h"

	#include <iostream>

	Geometry::Geometry(){
	}

	Geometry::~Geometry(){
	}

	void Geometry::render(){
		std::cout << "glError: " << glGetError() << std::endl;
		glBegin(GL_QUADS);
			glVertex3f(-1, 1, 0);
			glVertex3f(-1, -1, 0);
			glVertex3f(1, -1, 0);
			glVertex3f(1, 1, 0);
		glEnd();
	}


#endif