lesson14.cpp

关于OpenGL的实例教程源代码

/*
 *		This Code Was Created By Jeff Molofee 2000
 *		Modified by Shawn T. to handle (%3.2f, num) parameters.
 *		A HUGE Thanks To Fredric Echols For Cleaning Up
 *		And Optimizing The Base Code, Making It More Flexible!
 *		If You've Found This Code Useful, Please Let Me Know.
 *		Visit My Site At nehe.gamedev.net
 */

#include <windows.h>		// Header File For Windows
#include <math.h>			// Header File For Windows Math Library
#include <stdio.h>			// Header File For Standard Input/Output
#include <stdarg.h>			// Header File For Variable Argument Routines
#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

HDC			hDC=NULL;		// Private GDI Device Context
HGLRC		hRC=NULL;		// Permanent Rendering Context
HWND		hWnd=NULL;		// Holds Our Window Handle
HINSTANCE	hInstance;		// Holds The Instance Of The Application

GLuint	base;				// Base Display List For The Font Set
GLfloat	rot;				// Used To Rotate The Text

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

GLYPHMETRICSFLOAT gmf[256];	// Storage For Information About Our Outline Font Characters

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

GLvoid BuildFont(GLvoid)								// Build Our Bitmap Font
{
	HFONT	font;										// Windows Font ID

	base = glGenLists(256);								// Storage For 256 Characters

	font = CreateFont(	-12,							// Height Of Font
						0,								// Width Of Font
						0,								// Angle Of Escapement
						0,								// Orientation Angle
						FW_BOLD,						// Font Weight
						FALSE,							// Italic
						FALSE,							// Underline
						FALSE,							// Strikeout
						ANSI_CHARSET,					// Character Set Identifier
						OUT_TT_PRECIS,					// Output Precision
						CLIP_DEFAULT_PRECIS,			// Clipping Precision
						ANTIALIASED_QUALITY,			// Output Quality
						FF_DONTCARE|DEFAULT_PITCH,		// Family And Pitch
						"Comic Sans MS");				// Font Name

	SelectObject(hDC, font);							// Selects The Font We Created

	wglUseFontOutlines(	hDC,							// Select The Current DC
						0,								// Starting Character
						255,							// Number Of Display Lists To Build
						base,							// Starting Display Lists
						0.0f,							// Deviation From The True Outlines
						0.2f,							// Font Thickness In The Z Direction
						WGL_FONT_POLYGONS,				// Use Polygons, Not Lines
						gmf);							// Address Of Buffer To Recieve Data
}

GLvoid KillFont(GLvoid)									// Delete The Font
{
  glDeleteLists(base, 256);								// Delete All 256 Characters
}

GLvoid glPrint(const char *fmt, ...)					// Custom GL "Print" Routine
{
	float		length=0;								// Used To Find The Length Of The Text
	char		text[256];								// Holds Our String
	va_list		ap;										// Pointer To List Of Arguments

	if (fmt == NULL)									// If There's No Text
		return;											// Do Nothing

	va_start(ap, fmt);									// Parses The String For Variables
	    vsprintf(text, fmt, ap);						// And Converts Symbols To Actual Numbers
	va_end(ap);											// Results Are Stored In Text

	for (unsigned int loop=0;loop<(strlen(text));loop++)	// Loop To Find Text Length
	{
		length+=gmf[text[loop]].gmfCellIncX;			// Increase Length By Each Characters Width
	}

	glTranslatef(-length/2,0.0f,0.0f);					// Center Our Text On The Screen

	glPushAttrib(GL_LIST_BIT);							// Pushes The Display List Bits
	glListBase(base);									// Sets The Base Character to 0
	glCallLists(strlen(text), GL_UNSIGNED_BYTE, text);	// Draws The Display List Text
	glPopAttrib();										// Pops The Display List Bits
}

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);							// Enable Smooth Shading
	glClearColor(0.0f, 0.0f, 0.0f, 0.5f);				// Black Background
	glClearDepth(1.0f);									// Depth Buffer Setup
	glEnable(GL_DEPTH_TEST);							// Enables Depth Testing
	glDepthFunc(GL_LEQUAL);								// The Type Of Depth Testing To Do
	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);	// Really Nice Perspective Calculations
	glEnable(GL_LIGHT0);								// Enable Default Light (Quick And Dirty)
	glEnable(GL_LIGHTING);								// Enable Lighting
	glEnable(GL_COLOR_MATERIAL);						// Enable Coloring Of Material

	BuildFont();										// Build The Font

	return TRUE;										// Initialization Went OK
}

int DrawGLScene(GLvoid)									// Here's Where We Do All The Drawing
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	// Clear Screen And Depth Buffer
	glLoadIdentity();									// Reset The Current Modelview Matrix
	glTranslatef(0.0f,0.0f,-10.0f);						// Move One Unit Into The Screen
	glRotatef(rot,1.0f,0.0f,0.0f);						// Rotate On The X Axis
	glRotatef(rot*1.5f,0.0f,1.0f,0.0f);					// Rotate On The Y Axis
	glRotatef(rot*1.4f,0.0f,0.0f,1.0f);					// Rotate On The Z Axis
	// Pulsing Colors Based On The Rotation
	glColor3f(1.0f*float(cos(rot/20.0f)),1.0f*float(sin(rot/25.0f)),1.0f-0.5f*float(cos(rot/17.0f)));
 	glPrint("NeHe - %3.2f",rot/50);						// Print GL Text To The Screen
	rot+=0.5f;											// Increase The Rotation Variable
	return TRUE;										// Everything Went OK
}

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
	}

	KillFont();
}

/*	This Code Creates Our OpenGL Window.  Parameters Are:					*
 *	title			- Title To Appear At The Top Of The Window				*
 *	width			- Width Of The GL Window Or Fullscreen Mode				*
 *	height			- Height Of The GL Window Or Fullscreen Mode			*
 *	bits			- Number Of Bits To Use For Color (8/16/24/32)			*
 *	fullscreenflag	- Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE)	*/
 
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 Size, 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;											// 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,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)
		{
			// If The Mode Fails, Offer Two Options.  Quit Or Use Windowed Mode.
			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)