lesson31.cpp

关于OpenGL的实例教程源代码

/*
 *		This Code Was Created By Brett Porter For NeHe Productions 2000
 *		Visit NeHe Productions At http://nehe.gamedev.net
 *		
 *		Visit Brett Porter's Web Page at
 *		http://www.geocities.com/brettporter/programming
 */

#include <windows.h>												// Header File For Windows
#include <stdio.h>													// Header File For Standard Input/Output
#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 "MilkshapeModel.h"											// Header File For Milkshape File

#pragma comment( lib, "opengl32.lib" )								// Search For OpenGL32.lib While Linking ( NEW )
#pragma comment( lib, "glu32.lib" )									// Search For GLu32.lib While Linking    ( NEW )
#pragma comment( lib, "glaux.lib" )									// Search For GLaux.lib While Linking    ( NEW )

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

Model *pModel = NULL;												// Holds The Model Data

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

GLfloat	yrot=0.0f;													// Y Rotation

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

AUX_RGBImageRec *LoadBMP(const char *Filename)						// Loads A Bitmap Image
{
	FILE *File=NULL;												// File Handle

	if (!Filename)													// Make Sure A Filename Was Given
	{
		return NULL;												// If Not Return NULL
	}

	File=fopen(Filename,"r");										// Check To See If The File Exists

	if (File)														// Does The File Exist?
	{
		fclose(File);												// Close The Handle
		return auxDIBImageLoad(Filename);							// Load The Bitmap And Return A Pointer
	}

	return NULL;													// If Load Failed Return NULL
}

GLuint LoadGLTexture( const char *filename )						// Load Bitmaps And Convert To Textures
{
	AUX_RGBImageRec *pImage;										// Create Storage Space For The Texture
	GLuint texture = 0;												// Texture ID

	pImage = LoadBMP( filename );									// Loads The Bitmap Specified By filename

	// Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit
	if ( pImage != NULL && pImage->data != NULL )					// If Texture Image Exists
	{
		glGenTextures(1, &texture);									// Create The Texture

		// Typical Texture Generation Using Data From The Bitmap
		glBindTexture(GL_TEXTURE_2D, texture);
		glTexImage2D(GL_TEXTURE_2D, 0, 3, pImage->sizeX, pImage->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, pImage->data);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

		free(pImage->data);											// Free The Texture Image Memory
		free(pImage);												// Free The Image Structure
	}

	return texture;													// Return The Status
}

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,1.0f,1000.0f);	// View Depth of 1000

	glMatrixMode(GL_MODELVIEW);										// Select The Modelview Matrix
	glLoadIdentity();												// Reset The Modelview Matrix
}

int InitGL(GLvoid)													// All Setup For OpenGL Goes Here
{
	pModel->reloadTextures();										// Loads Model Textures

	glEnable(GL_TEXTURE_2D);										// Enable Texture Mapping ( NEW )
	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
	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 The Screen And The Depth Buffer
	glLoadIdentity();												// Reset The Modelview Matrix
	gluLookAt( 75, 75, 75, 0, 0, 0, 0, 1, 0 );						// (3) Eye Postion (3) Center Point (3) Y-Axis Up Vector

	glRotatef(yrot,0.0f,1.0f,0.0f);									// Rotate On The Y-Axis By yrot

	pModel->draw();													// Draw The Model

	yrot+=1.0f;														// Increase yrot By One
	return TRUE;													// Keep Going
}

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
	}
}

/*	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)
			{
				fullscreen=FALSE;									// Windowed Mode Selected.  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;										// Return FALSE
			}
		}
	}

	if (fullscreen)													// Are We Still In Fullscreen Mode?
	{
		dwExStyle=WS_EX_APPWINDOW;									// Window Extended Style