lesson17.cpp

关于OpenGL的实例教程源代码

/*
 *		This Code Was Created By Jeff Molofee 2000
 *		And Modified By Giuseppe D'Agata ([e-mail])
 *		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 <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

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

GLuint	base;				// Base Display List For The Font
GLuint	texture[2];			// Storage For Our Font Texture
GLuint	loop;				// Generic Loop Variable

GLfloat	cnt1;				// 1st Counter Used To Move Text & For Coloring
GLfloat	cnt2;				// 2nd Counter Used To Move Text & For Coloring

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

AUX_RGBImageRec *LoadBMP(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
}

int LoadGLTextures()                                    // Load Bitmaps And Convert To Textures
{
        int Status=FALSE;                               // Status Indicator
        AUX_RGBImageRec *TextureImage[2];               // Create Storage Space For The Textures
        memset(TextureImage,0,sizeof(void *)*2);        // Set The Pointer To NULL

        if ((TextureImage[0]=LoadBMP("Data/Font.bmp")) &&
			(TextureImage[1]=LoadBMP("Data/Bumps.bmp")))
        {
                Status=TRUE;                            // Set The Status To TRUE
                glGenTextures(2, &texture[0]);          // Create Two Texture

				for (loop=0; loop<2; loop++)
				{
	                glBindTexture(GL_TEXTURE_2D, texture[loop]);
			        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, 3, TextureImage[loop]->sizeX, TextureImage[loop]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[loop]->data);
				}
        }
		for (loop=0; loop<2; loop++)
		{
	        if (TextureImage[loop])							// If Texture Exists
		    {
			        if (TextureImage[loop]->data)			// If Texture Image Exists
				    {
					        free(TextureImage[loop]->data);	// Free The Texture Image Memory
					}
					free(TextureImage[loop]);				// Free The Image Structure
			}
		}
        return Status;                                  // Return The Status
}

GLvoid BuildFont(GLvoid)								// Build Our Font Display List
{
	float	cx;											// Holds Our X Character Coord
	float	cy;											// Holds Our Y Character Coord

	base=glGenLists(256);								// Creating 256 Display Lists
	glBindTexture(GL_TEXTURE_2D, texture[0]);			// Select Our Font Texture
	for (loop=0; loop<256; loop++)						// Loop Through All 256 Lists
	{
		cx=float(loop%16)/16.0f;						// X Position Of Current Character
		cy=float(loop/16)/16.0f;						// Y Position Of Current Character

		glNewList(base+loop,GL_COMPILE);				// Start Building A List
			glBegin(GL_QUADS);							// Use A Quad For Each Character
				glTexCoord2f(cx,1-cy-0.0625f);			// Texture Coord (Bottom Left)
				glVertex2i(0,0);						// Vertex Coord (Bottom Left)
				glTexCoord2f(cx+0.0625f,1-cy-0.0625f);	// Texture Coord (Bottom Right)
				glVertex2i(16,0);						// Vertex Coord (Bottom Right)
				glTexCoord2f(cx+0.0625f,1-cy);			// Texture Coord (Top Right)
				glVertex2i(16,16);						// Vertex Coord (Top Right)
				glTexCoord2f(cx,1-cy);					// Texture Coord (Top Left)
				glVertex2i(0,16);						// Vertex Coord (Top Left)
			glEnd();									// Done Building Our Quad (Character)
			glTranslated(10,0,0);						// Move To The Right Of The Character
		glEndList();									// Done Building The Display List
	}													// Loop Until All 256 Are Built
}

GLvoid KillFont(GLvoid)									// Delete The Font From Memory
{
	glDeleteLists(base,256);							// Delete All 256 Display Lists
}

GLvoid glPrint(GLint x, GLint y, char *string, int set)	// Where The Printing Happens
{
	if (set>1)
	{
		set=1;
	}
	glBindTexture(GL_TEXTURE_2D, texture[0]);			// Select Our Font Texture
	glDisable(GL_DEPTH_TEST);							// Disables Depth Testing
	glMatrixMode(GL_PROJECTION);						// Select The Projection Matrix
	glPushMatrix();										// Store The Projection Matrix
	glLoadIdentity();									// Reset The Projection Matrix
	glOrtho(0,640,0,480,-1,1);							// Set Up An Ortho Screen
	glMatrixMode(GL_MODELVIEW);							// Select The Modelview Matrix
	glPushMatrix();										// Store The Modelview Matrix
	glLoadIdentity();									// Reset The Modelview Matrix
	glTranslated(x,y,0);								// Position The Text (0,0 - Bottom Left)
	glListBase(base-32+(128*set));						// Choose The Font Set (0 or 1)
	glCallLists(strlen(string),GL_UNSIGNED_BYTE,string);// Write The Text To The Screen
	glMatrixMode(GL_PROJECTION);						// Select The Projection Matrix
	glPopMatrix();										// Restore The Old Projection Matrix
	glMatrixMode(GL_MODELVIEW);							// Select The Modelview Matrix
	glPopMatrix();										// Restore The Old Projection Matrix
	glEnable(GL_DEPTH_TEST);							// Enables Depth Testing
}

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
	gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);	// Calculate Window Aspect Ratio
	glMatrixMode(GL_MODELVIEW);							// Select The Modelview Matrix
	glLoadIdentity();									// Reset The Modelview Matrix
}

int InitGL(GLvoid)										// All Setup For OpenGL Goes Here
{
	if (!LoadGLTextures())								// Jump To Texture Loading Routine
	{
		return FALSE;									// If Texture Didn't Load Return FALSE
	}
	BuildFont();										// Build The Font
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);				// Clear The Background Color To Black
	glClearDepth(1.0);									// Enables Clearing Of The Depth Buffer
	glDepthFunc(GL_LEQUAL);								// The Type Of Depth Test To Do
	glBlendFunc(GL_SRC_ALPHA,GL_ONE);					// Select The Type Of Blending
	glShadeModel(GL_SMOOTH);							// Enables Smooth Color Shading
	glEnable(GL_TEXTURE_2D);							// Enable 2D Texture Mapping
	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
	glBindTexture(GL_TEXTURE_2D, texture[1]);			// Select Our Second Texture
	glTranslatef(0.0f,0.0f,-5.0f);						// Move Into The Screen 5 Units
	glRotatef(45.0f,0.0f,0.0f,1.0f);					// Rotate On The Z Axis 45 Degrees (Clockwise)
	glRotatef(cnt1*30.0f,1.0f,1.0f,0.0f);				// Rotate On The X & Y Axis By cnt1 (Left To Right)
	glDisable(GL_BLEND);								// Disable Blending Before We Draw In 3D
	glColor3f(1.0f,1.0f,1.0f);							// Bright White
	glBegin(GL_QUADS);									// Draw Our First Texture Mapped Quad
		glTexCoord2d(0.0f,0.0f);						// First Texture Coord
		glVertex2f(-1.0f, 1.0f);						// First Vertex
		glTexCoord2d(1.0f,0.0f);						// Second Texture Coord
		glVertex2f( 1.0f, 1.0f);						// Second Vertex
		glTexCoord2d(1.0f,1.0f);						// Third Texture Coord
		glVertex2f( 1.0f,-1.0f);						// Third Vertex
		glTexCoord2d(0.0f,1.0f);						// Fourth Texture Coord
		glVertex2f(-1.0f,-1.0f);						// Fourth Vertex
	glEnd();											// Done Drawing The First Quad
	glRotatef(90.0f,1.0f,1.0f,0.0f);					// Rotate On The X & Y Axis By 90 Degrees (Left To Right)
	glBegin(GL_QUADS);									// Draw Our Second Texture Mapped Quad
		glTexCoord2d(0.0f,0.0f);						// First Texture Coord
		glVertex2f(-1.0f, 1.0f);						// First Vertex
		glTexCoord2d(1.0f,0.0f);						// Second Texture Coord
		glVertex2f( 1.0f, 1.0f);						// Second Vertex
		glTexCoord2d(1.0f,1.0f);						// Third Texture Coord
		glVertex2f( 1.0f,-1.0f);						// Third Vertex
		glTexCoord2d(0.0f,1.0f);						// Fourth Texture Coord
		glVertex2f(-1.0f,-1.0f);						// Fourth Vertex
	glEnd();											// Done Drawing Our Second Quad
	glEnable(GL_BLEND);									// Enable Blending

	glLoadIdentity();									// Reset The View
	// Pulsing Colors Based On Text Position
	glColor3f(1.0f*float(cos(cnt1)),1.0f*float(sin(cnt2)),1.0f-0.5f*float(cos(cnt1+cnt2)));
	glPrint(int((280+250*cos(cnt1))),int(235+200*sin(cnt2)),"NeHe",0);		// Print GL Text To The Screen

	glColor3f(1.0f*float(sin(cnt2)),1.0f-0.5f*float(cos(cnt1+cnt2)),1.0f*float(cos(cnt1)));
	glPrint(int((280+230*cos(cnt2))),int(235+200*sin(cnt1)),"OpenGL",1);	// Print GL Text To The Screen

	glColor3f(0.0f,0.0f,1.0f);							// Set Color To Blue
	glPrint(int(240+200*cos((cnt2+cnt1)/5)),2,"Giuseppe D'Agata",0);

	glColor3f(1.0f,1.0f,1.0f);							// Set Color To White
	glPrint(int(242+200*cos((cnt2+cnt1)/5)),2,"Giuseppe D'Agata",0);

	cnt1+=0.01f;										// Increase The First Counter
	cnt2+=0.0081f;										// Increase The Second Counter
	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();											// Kill The Font
}

/*	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