nehegl.cpp

关于OpenGL的实例教程源代码

/***********************************************
*                                              *
*    Jeff Molofee's Revised OpenGL Basecode    *
*  Huge Thanks To Maxwell Sayles & Peter Puck  *
*            http://nehe.gamedev.net           *
*                     2001                     *
*                                              *
***********************************************/

#include <windows.h>													// Header File For The Windows Library
#include <gl/gl.h>														// Header File For The OpenGL32 Library
#include <gl/glu.h>														// Header File For The GLu32 Library

#include "NeHeGL.h"														// Header File For The NeHeGL Basecode

#define WM_TOGGLEFULLSCREEN (WM_USER+1)									// Application Define Message For Toggling

static BOOL g_isProgramLooping;											// Window Creation Loop, For FullScreen/Windowed Toggle																		// Between Fullscreen / Windowed Mode
static BOOL g_createFullScreen;											// If TRUE, Then Create Fullscreen

void TerminateApplication (GL_Window* window)							// Terminate The Application
{
	PostMessage (window->hWnd, WM_QUIT, 0, 0);							// Send A WM_QUIT Message
	g_isProgramLooping = FALSE;											// Stop Looping Of The Program
}

void ToggleFullscreen (GL_Window* window)								// Toggle Fullscreen/Windowed
{
	PostMessage (window->hWnd, WM_TOGGLEFULLSCREEN, 0, 0);				// Send A WM_TOGGLEFULLSCREEN Message
}

void ReshapeGL (int width, int height)									// Reshape The Window When It's Moved Or Resized
{
	glViewport (0, 0, (GLsizei)(width), (GLsizei)(height));				// Reset The Current Viewport
	glMatrixMode (GL_PROJECTION);										// Select The Projection Matrix
	glLoadIdentity ();													// Reset The Projection Matrix
	gluPerspective(50, (float)width/(float)height, 5,  2000);
	glMatrixMode (GL_MODELVIEW);										// Select The Modelview Matrix
	glLoadIdentity ();													// Reset The Modelview Matrix
}

BOOL ChangeScreenResolution (int width, int height, int bitsPerPixel)	// Change The Screen Resolution
{
	DEVMODE dmScreenSettings;											// Device Mode
	ZeroMemory (&dmScreenSettings, sizeof (DEVMODE));					// Make Sure Memory Is Cleared
	dmScreenSettings.dmSize				= sizeof (DEVMODE);				// Size Of The Devmode Structure
	dmScreenSettings.dmPelsWidth		= width;						// Select Screen Width
	dmScreenSettings.dmPelsHeight		= height;						// Select Screen Height
	dmScreenSettings.dmBitsPerPel		= bitsPerPixel;					// Select Bits Per Pixel
	dmScreenSettings.dmFields			= DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;
	if (ChangeDisplaySettings (&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
	{
		return FALSE;													// Display Change Failed, Return False
	}
	return TRUE;														// Display Change Was Successful, Return True
}

BOOL CreateWindowGL (GL_Window* window)									// This Code Creates Our OpenGL Window
{
	DWORD windowStyle = WS_OVERLAPPEDWINDOW;							// Define Our Window Style
	DWORD windowExtendedStyle = WS_EX_APPWINDOW;						// Define The Window's Extended Style

	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
		window->init.bitsPerPixel,										// Select Our Color Depth
		0, 0, 0, 0, 0, 0,												// Color Bits Ignored
		1,																// 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
	};

	RECT windowRect = {0, 0, window->init.width, window->init.height};	// Define Our Window Coordinates

	GLuint PixelFormat;													// Will Hold The Selected Pixel Format

	if (window->init.isFullScreen == TRUE)								// Fullscreen Requested, Try Changing Video Modes
	{
		if (ChangeScreenResolution (window->init.width, window->init.height, window->init.bitsPerPixel) == FALSE)
		{
			// Fullscreen Mode Failed.  Run In Windowed Mode Instead
			MessageBox (HWND_DESKTOP, "Mode Switch Failed.\nRunning In Windowed Mode.", "Error", MB_OK | MB_ICONEXCLAMATION);
			window->init.isFullScreen = FALSE;							// Set isFullscreen To False (Windowed Mode)
		}
		else															// Otherwise (If Fullscreen Mode Was Successful)
		{
			ShowCursor (FALSE);											// Turn Off The Cursor
			windowStyle = WS_POPUP;										// Set The WindowStyle To WS_POPUP (Popup Window)
			windowExtendedStyle |= WS_EX_TOPMOST;						// Set The Extended Window Style To WS_EX_TOPMOST
		}																// (Top Window Covering Everything Else)
	}
	else																// If Fullscreen Was Not Selected
	{
		// Adjust Window, Account For Window Borders
		AdjustWindowRectEx (&windowRect, windowStyle, 0, windowExtendedStyle);
	}

	// Create The OpenGL Window
	window->hWnd = CreateWindowEx (windowExtendedStyle,					// Extended Style
								   window->init.application->className,	// Class Name
								   window->init.title,					// Window Title
								   windowStyle,							// Window Style
								   0, 0,								// Window X,Y Position
								   windowRect.right - windowRect.left,	// Window Width
								   windowRect.bottom - windowRect.top,	// Window Height
								   HWND_DESKTOP,						// Desktop Is Window's Parent
								   0,									// No Menu
								   window->init.application->hInstance, // Pass The Window Instance
								   window);

	if (window->hWnd == 0)												// Was Window Creation A Success?
	{
		return FALSE;													// If Not Return False
	}

	window->hDC = GetDC (window->hWnd);									// Grab A Device Context For This Window
	if (window->hDC == 0)												// Did We Get A Device Context?
	{
		// Failed
		DestroyWindow (window->hWnd);									// Destroy The Window
		window->hWnd = 0;												// Zero The Window Handle
		return FALSE;													// Return False
	}

	PixelFormat = ChoosePixelFormat (window->hDC, &pfd);				// Find A Compatible Pixel Format
	if (PixelFormat == 0)												// Did We Find A Compatible Format?
	{
		// Failed
		ReleaseDC (window->hWnd, window->hDC);							// Release Our Device Context
		window->hDC = 0;												// Zero The Device Context
		DestroyWindow (window->hWnd);									// Destroy The Window
		window->hWnd = 0;												// Zero The Window Handle
		return FALSE;													// Return False
	}

	if (SetPixelFormat (window->hDC, PixelFormat, &pfd) == FALSE)		// Try To Set The Pixel Format
	{
		// Failed
		ReleaseDC (window->hWnd, window->hDC);							// Release Our Device Context
		window->hDC = 0;												// Zero The Device Context
		DestroyWindow (window->hWnd);									// Destroy The Window
		window->hWnd = 0;												// Zero The Window Handle
		return FALSE;													// Return False
	}

	window->hRC = wglCreateContext (window->hDC);						// Try To Get A Rendering Context
	if (window->hRC == 0)												// Did We Get A Rendering Context?
	{
		// Failed
		ReleaseDC (window->hWnd, window->hDC);							// Release Our Device Context
		window->hDC = 0;												// Zero The Device Context
		DestroyWindow (window->hWnd);									// Destroy The Window
		window->hWnd = 0;												// Zero The Window Handle
		return FALSE;													// Return False
	}

	// Make The Rendering Context Our Current Rendering Context
	if (wglMakeCurrent (window->hDC, window->hRC) == FALSE)
	{
		// Failed
		wglDeleteContext (window->hRC);									// Delete The Rendering Context
		window->hRC = 0;												// Zero The Rendering Context
		ReleaseDC (window->hWnd, window->hDC);							// Release Our Device Context
		window->hDC = 0;												// Zero The Device Context
		DestroyWindow (window->hWnd);									// Destroy The Window
		window->hWnd = 0;												// Zero The Window Handle
		return FALSE;													// Return False
	}

	ShowWindow (window->hWnd, SW_NORMAL);								// Make The Window Visible
	window->isVisible = TRUE;											// Set isVisible To True

	ReshapeGL (window->init.width, window->init.height);				// Reshape Our GL Window

	ZeroMemory (window->keys, sizeof (Keys));							// Clear All Keys

	window->lastTickCount = GetTickCount ();							// Get Tick Count

	return TRUE;														// Window Creating Was A Success
																		// Initialization Will Be Done In WM_CREATE
}

BOOL DestroyWindowGL (GL_Window* window)								// Destroy The OpenGL Window & Release Resources
{
	if (window->hWnd != 0)												// Does The Window Have A Handle?
	{	
		if (window->hDC != 0)											// Does The Window Have A Device Context?
		{
			wglMakeCurrent (window->hDC, 0);							// Set The Current Active Rendering Context To Zero
			if (window->hRC != 0)										// Does The Window Have A Rendering Context?
			{
				wglDeleteContext (window->hRC);							// Release The Rendering Context
				window->hRC = 0;										// Zero The Rendering Context

			}
			ReleaseDC (window->hWnd, window->hDC);						// Release The Device Context
			window->hDC = 0;											// Zero The Device Context
		}
		DestroyWindow (window->hWnd);									// Destroy The Window
		window->hWnd = 0;												// Zero The Window Handle
	}