lesson22.cpp

关于OpenGL的实例教程源代码

/*		This Code Was Created by Jens Schneider (WizardSoft) 2000 
 *		Lesson22 to the series of OpenGL tutorials by NeHe-Production
 *
 *		This Code is loosely based upon Lesson06 by Jeff Molofee.
 *
 *		contact me at: [e-mail]
 *
 *		Basecode Was Created By Jeff Molofee 2000
 *		If You've Found This Code Useful, Please Let Me Know.
 *		Visit My Site At nehe.gamedev.net
 */

// [HTML]: Point Out That Bump Maps Have To Be "Sharper" To Do Nice Effects!
#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 "glext.h"													// Header File For Multitexturing
#include <string.h>													// Header File For The String Library
#include <math.h>													// Header File For The Math Library

#define MAX_EMBOSS (GLfloat)0.008f	// Maximum Emboss-Translate. Increase To Get Higher Immersion
									// At A Cost Of Lower Quality (More Artifacts Will Occur!)

/*	Here Comes The ARB-Multitexture Support.
 *	There Are (Optimally) 6 New Commands To The OpenGL Set:
 *	glMultiTexCoordifARB i=1..4	: Sets Texture-Coordinates For Texel-Pipeline #i
 *	glActiveTextureARB			: Sets Active Texel-Pipeline
 *	glClientActiveTextureARB	: Sets Active Texel-Pipeline For The Pointer-Array-Commands
 *
 *	There Are Even More For The Various Formats Of glMultiTexCoordi{f,fv,d,i}, But We Don't Need Them.
 */

#define __ARB_ENABLE true											// Used To Disable ARB Extensions Entirely

// #define EXT_INFO													// Do You Want To See Your Extensions At Start-Up?
#define MAX_EXTENSION_SPACE 10240									// Characters for Extension-Strings
#define MAX_EXTENSION_LENGTH 256									// Maximum Of Characters In One Extension-String
bool multitextureSupported=false;									// Flag Indicating Whether Multitexturing Is Supported
bool useMultitexture=true;											// Use It If It Is Supported?
GLint maxTexelUnits=1;												// Number Of Texel-Pipelines. This Is At Least 1.

PFNGLMULTITEXCOORD1FARBPROC		glMultiTexCoord1fARB	= NULL;
PFNGLMULTITEXCOORD2FARBPROC		glMultiTexCoord2fARB	= NULL;
PFNGLMULTITEXCOORD3FARBPROC		glMultiTexCoord3fARB	= NULL;
PFNGLMULTITEXCOORD4FARBPROC		glMultiTexCoord4fARB	= NULL;
PFNGLACTIVETEXTUREARBPROC		glActiveTextureARB		= NULL;
PFNGLCLIENTACTIVETEXTUREARBPROC	glClientActiveTextureARB= NULL;	

HDC		hDC=NULL;													// Private GDI Device Context
HGLRC	hRC=NULL;													// Permanent Rendering Context
HWND	hWnd=NULL;													// Holds Our Window Handle

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
bool	emboss=false;												// Emboss Only, No Basetexture?
bool    bumps=true;													// Do Bumpmapping?

GLfloat	xrot;														// X Rotation
GLfloat	yrot;														// Y Rotation
GLfloat xspeed;														// X Rotation Speed
GLfloat yspeed;														// Y Rotation Speed
GLfloat	z=-5.0f;													// Depth Into The Screen

GLuint	filter=1;													// Which Filter To Use
GLuint	texture[3];													// Storage For 3 Textures
GLuint  bump[3];													// Our Bumpmappings
GLuint  invbump[3];													// Inverted Bumpmaps
GLuint	glLogo;														// Handle For OpenGL-Logo
GLuint  multiLogo;													// Handle For Multitexture-Enabled-Logo

GLfloat LightAmbient[]	= { 0.2f, 0.2f, 0.2f};						// Ambient Light is 20% white
GLfloat LightDiffuse[]	= { 1.0f, 1.0f, 1.0f};						// Diffuse Light is white
GLfloat LightPosition[] = { 0.0f, 0.0f, 2.0f};						// Position is somewhat in front of screen

GLfloat Gray[]= {0.5f,0.5f,0.5f,1.0f};

// Data Contains The Faces For The Cube In Format 2xTexCoord, 3xVertex;
// Note That The Tesselation Of The Cube Is Only Absolute Minimum.
GLfloat data[]= {
		// FRONT FACE
		0.0f, 0.0f,		-1.0f, -1.0f, +1.0f,
		1.0f, 0.0f,		+1.0f, -1.0f, +1.0f,
		1.0f, 1.0f,		+1.0f, +1.0f, +1.0f,
		0.0f, 1.0f,		-1.0f, +1.0f, +1.0f,
		// BACK FACE
		1.0f, 0.0f,		-1.0f, -1.0f, -1.0f,
		1.0f, 1.0f,		-1.0f, +1.0f, -1.0f,
		0.0f, 1.0f,		+1.0f, +1.0f, -1.0f,
		0.0f, 0.0f,		+1.0f, -1.0f, -1.0f,
		// Top Face
		0.0f, 1.0f,		-1.0f, +1.0f, -1.0f,
		0.0f, 0.0f,		-1.0f, +1.0f, +1.0f,
		1.0f, 0.0f,		+1.0f, +1.0f, +1.0f,
		1.0f, 1.0f,		+1.0f, +1.0f, -1.0f,
		// Bottom Face
		1.0f, 1.0f,		-1.0f, -1.0f, -1.0f,
		0.0f, 1.0f,		+1.0f, -1.0f, -1.0f,
		0.0f, 0.0f,		+1.0f, -1.0f, +1.0f,
		1.0f, 0.0f,		-1.0f, -1.0f, +1.0f,
		// Right Face
		1.0f, 0.0f,		+1.0f, -1.0f, -1.0f,
		1.0f, 1.0f,		+1.0f, +1.0f, -1.0f,
		0.0f, 1.0f,		+1.0f, +1.0f, +1.0f,
		0.0f, 0.0f,		+1.0f, -1.0f, +1.0f,
		// Left Face
		0.0f, 0.0f,		-1.0f, -1.0f, -1.0f,
		1.0f, 0.0f,		-1.0f, -1.0f,  1.0f,
		1.0f, 1.0f,		-1.0f,  1.0f,  1.0f,
		0.0f, 1.0f,		-1.0f,  1.0f, -1.0f
};

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

// Always Check For Extension-Availability During Run-Time!
// Here We Go!
bool isInString(char *string, const char *search) {
	int pos=0;
	int maxpos=strlen(search)-1;
	int len=strlen(string);	
	char *other;
	for (int i=0; i<len; i++) {
		if ((i==0) || ((i>1) && string[i-1]=='\n')) {				// New Extension Begins Here!
			other=&string[i];			
			pos=0;													// Begin New Search
			while (string[i]!='\n') {								// Search Whole Extension-String
				if (string[i]==search[pos]) pos++;					// Next Position
				if ((pos>maxpos) && string[i+1]=='\n') return true; // We Have A Winner!
				i++;
			}			
		}
	}	
	return false;													// Sorry, Not Found!
}

// isMultitextureSupported() Checks At Run-Time If Multitexturing Is Supported
bool initMultitexture(void) {
	char *extensions;	
	extensions=strdup((char *) glGetString(GL_EXTENSIONS));			// Fetch Extension String
	int len=strlen(extensions);
	for (int i=0; i<len; i++)										// Separate It By Newline Instead Of Blank
		if (extensions[i]==' ') extensions[i]='\n';

#ifdef EXT_INFO
	MessageBox(hWnd,extensions,"supported GL extensions",MB_OK | MB_ICONINFORMATION);
#endif

	if (isInString(extensions,"GL_ARB_multitexture")				// Is Multitexturing Supported?
		&& __ARB_ENABLE												// Override-Flag
		&& isInString(extensions,"GL_EXT_texture_env_combine"))		// Is texture_env_combining Supported?
	{	
		glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB,&maxTexelUnits);
		glMultiTexCoord1fARB	= (PFNGLMULTITEXCOORD1FARBPROC)		wglGetProcAddress("glMultiTexCoord1fARB");
		glMultiTexCoord2fARB	= (PFNGLMULTITEXCOORD2FARBPROC)		wglGetProcAddress("glMultiTexCoord2fARB");
		glMultiTexCoord3fARB	= (PFNGLMULTITEXCOORD3FARBPROC)		wglGetProcAddress("glMultiTexCoord3fARB");
		glMultiTexCoord4fARB	= (PFNGLMULTITEXCOORD4FARBPROC)		wglGetProcAddress("glMultiTexCoord4fARB");
		glActiveTextureARB		= (PFNGLACTIVETEXTUREARBPROC)		wglGetProcAddress("glActiveTextureARB");
		glClientActiveTextureARB= (PFNGLCLIENTACTIVETEXTUREARBPROC)	wglGetProcAddress("glClientActiveTextureARB");		
#ifdef EXT_INFO
	MessageBox(hWnd,"The GL_ARB_multitexture extension will be used.","feature supported!",MB_OK | MB_ICONINFORMATION);
#endif
		return true;
	}
	useMultitexture=false;											// We Can't Use It If It Isn't Supported!
	return false;
}

void initLights(void) {

	glLightfv( GL_LIGHT1, GL_AMBIENT, LightAmbient);				// Load Light-Parameters Into GL_LIGHT1
	glLightfv( GL_LIGHT1, GL_DIFFUSE, LightDiffuse);	
	glLightfv( GL_LIGHT1, GL_POSITION, LightPosition);

	glEnable(GL_LIGHT1);	
}

// Using auxDIBImageLoad's Own Error-Handler!
int LoadGLTextures(){												// Load Bitmaps And Convert To Textures
	bool status=true;												// Status Indicator
	AUX_RGBImageRec *Image=NULL;									// Create Storage Space For The Texture
	char *alpha=NULL;

	// Load The Tile-Bitmap For Base-Texture
	if (Image=auxDIBImageLoad("Data/Base.bmp")) {											
		glGenTextures(3, texture);									// Create Three Textures

		// Create Nearest Filtered Texture
		glBindTexture(GL_TEXTURE_2D, texture[0]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, Image->sizeX, Image->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, Image->data);
		//                             ========
		// Use GL_RGB8 Instead Of "3" In glTexImage2D. Also Defined By GL: GL_RGBA8 Etc.
		// NEW: Now Creating GL_RGBA8 Textures, Alpha Is 1.0f Where Not Specified By Format.

		// Create Linear Filtered Texture
		glBindTexture(GL_TEXTURE_2D, texture[1]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, Image->sizeX, Image->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, Image->data);

		// Create MipMapped Texture
		glBindTexture(GL_TEXTURE_2D, texture[2]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
		gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGB8, Image->sizeX, Image->sizeY, GL_RGB, GL_UNSIGNED_BYTE, Image->data);
	}
	else status=false;
	if (Image) {													// If Texture Exists
		if (Image->data) delete Image->data;						// If Texture Image Exists
		delete Image;
		Image=NULL;
	}	
	
	// Load The Bumpmaps
	if (Image=auxDIBImageLoad("Data/Bump.bmp")) {			
		glPixelTransferf(GL_RED_SCALE,0.5f);						// Scale RGB By 50%, So That We Have Only			
		glPixelTransferf(GL_GREEN_SCALE,0.5f);						// Half Intenstity
		glPixelTransferf(GL_BLUE_SCALE,0.5f);

		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP);	// No Wrapping, Please!
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP);
		glTexParameterfv(GL_TEXTURE_2D,GL_TEXTURE_BORDER_COLOR,Gray);

		glGenTextures(3, bump);										// Create Three Textures

		// Create Nearest Filtered Texture
		glBindTexture(GL_TEXTURE_2D, bump[0]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, Image->sizeX, Image->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, Image->data);
		
		// Create Linear Filtered Texture
		glBindTexture(GL_TEXTURE_2D, bump[1]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, Image->sizeX, Image->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, Image->data);

		// Create MipMapped Texture
		glBindTexture(GL_TEXTURE_2D, bump[2]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
		gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGB8, Image->sizeX, Image->sizeY, GL_RGB, GL_UNSIGNED_BYTE, Image->data);
		
		for (int i=0; i<3*Image->sizeX*Image->sizeY; i++)		// Invert The Bumpmap
			Image->data[i]=255-Image->data[i];

		glGenTextures(3, invbump);								// Create Three Textures

		// Create Nearest Filtered Texture
		glBindTexture(GL_TEXTURE_2D, invbump[0]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, Image->sizeX, Image->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, Image->data);
		
		// Create Linear Filtered Texture
		glBindTexture(GL_TEXTURE_2D, invbump[1]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, Image->sizeX, Image->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, Image->data);

		// Create MipMapped Texture
		glBindTexture(GL_TEXTURE_2D, invbump[2]);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
		gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGB8, Image->sizeX, Image->sizeY, GL_RGB, GL_UNSIGNED_BYTE, Image->data);
		
		glPixelTransferf(GL_RED_SCALE,1.0f);				// Scale RGB Back To 100% Again		
		glPixelTransferf(GL_GREEN_SCALE,1.0f);			
		glPixelTransferf(GL_BLUE_SCALE,1.0f);
	}
	else status=false;
	if (Image) {											// If Texture Exists
		if (Image->data) delete Image->data;				// If Texture Image Exists
		delete Image;
	}

	// Load The Logo-Bitmaps
	if (Image=auxDIBImageLoad("Data/OpenGL_ALPHA.bmp")) {							
		alpha=new char[4*Image->sizeX*Image->sizeY];		// Create Memory For RGBA8-Texture
		for (int a=0; a<Image->sizeX*Image->sizeY; a++)
			alpha[4*a+3]=Image->data[a*3];					// Pick Only Red Value As Alpha!
		if (!(Image=auxDIBImageLoad("Data/OpenGL.bmp"))) status=false;
		for (a=0; a<Image->sizeX*Image->sizeY; a++) {		
			alpha[4*a]=Image->data[a*3];					// R
			alpha[4*a+1]=Image->data[a*3+1];				// G
			alpha[4*a+2]=Image->data[a*3+2];				// B
		}
					
		glGenTextures(1, &glLogo);							// Create One Textures

		// Create Linear Filtered RGBA8-Texture
		glBindTexture(GL_TEXTURE_2D, glLogo);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, Image->sizeX, Image->sizeY, 0, GL_RGBA, GL_UNSIGNED_BYTE, alpha);
		delete alpha;
	}
	else status=false;
	if (Image) {											// If Texture Exists
		if (Image->data) delete Image->data;				// If Texture Image Exists
		delete Image;
		Image=NULL;
	}	
	
	// Load The "Extension Enabled"-Logo