main.cpp

来自「一本关于OPenGL的很好的电子书」· C++ 代码 · 共 351 行

#define WIN32_LEAN_AND_MEAN				// trim the excess fat from Windows

/*****************************************************

	Chapter 6 - Light Example 1 - Rotating, Lit Cube
	Kevin Hawkins, Dave Astle

	Description: Displays a rotating, lit cube

******************************************************/

////// Includes
#include <windows.h>					// standard Windows app include
#include <gl/gl.h>						// standard OpenGL include
#include <gl/glu.h>						// OpenGL utilties
#include <gl/glaux.h>					// OpenGL auxiliary functions

////// Global Variables
float angle = 0.0f;						// current angle of the rotating triangle
HDC g_HDC;								// global device context
bool fullScreen = false;					

////// Lighting variables
float ambientLight[] = { 0.3f, 0.5f, 0.8f, 1.0f };	// ambient light
float diffuseLight[] = { 0.25f, 0.25f, 0.25f, 1.0f };	// diffuse light
float lightPosition[] = { 0.0f, 0.0f, 1.0f, 0.0f };	// the light position

////// Material variables
float matAmbient[] = { 1.0f, 1.0f, 1.0f, 1.0f };
float matDiff[] = { 1.0f, 1.0f, 1.0f, 1.0f};

// Initialize
// desc: initializes OpenGL
void Initialize()
{
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);		// clear to black

	glShadeModel(GL_SMOOTH);					// use smooth shading
	glEnable(GL_DEPTH_TEST);					// hidden surface removal
	glEnable(GL_CULL_FACE);						// do not calculate inside of poly's
	glFrontFace(GL_CCW);						// counter clock-wise polygons are out

	glEnable(GL_LIGHTING);						// enable lighting

	// Setup the materials for LIGHT0
	glMaterialfv(GL_FRONT, GL_AMBIENT, matAmbient);
	glMaterialfv(GL_FRONT, GL_DIFFUSE, matDiff);

	// Now setup LIGHT0
	glLightfv(GL_LIGHT0, GL_AMBIENT, ambientLight);		// setup the ambient element
	glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseLight);		// the diffuse element
	glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);	// place the light in the world

	// Enable the light
	glEnable(GL_LIGHT0);
}

// DrawCube
// desc: draws a cube at the specified location in
//		 the current coordinate space
void DrawCube(float xPos, float yPos, float zPos)
{
	glPushMatrix();
		glTranslatef(xPos, yPos, zPos);
		glBegin(GL_POLYGON);
			glNormal3f(0.0f, 1.0f, 0.0f);	// top face
			glVertex3f(0.5f, 0.5f, 0.5f);	
			glVertex3f(0.5f, 0.5f, -0.5f);
			glVertex3f(-0.5f, 0.5f, -0.5f);
			glVertex3f(-0.5f, 0.5f, 0.5f);
		glEnd();
		glBegin(GL_POLYGON);
			glNormal3f(0.0f, 0.0f, 1.0f);	// front face
			glVertex3f(0.5f, 0.5f, 0.5f);	
			glVertex3f(-0.5f, 0.5f, 0.5f);
			glVertex3f(-0.5f, -0.5f, 0.5f);
			glVertex3f(0.5f, -0.5f, 0.5f);
		glEnd();
		glBegin(GL_POLYGON);
			glNormal3f(1.0f, 0.0f, 0.0f);	// right face
			glVertex3f(0.5f, 0.5f, 0.5f);	
			glVertex3f(0.5f, -0.5f, 0.5f);
			glVertex3f(0.5f, -0.5f, -0.5f);
			glVertex3f(0.5f, 0.5f, -0.5f);
		glEnd();
		glBegin(GL_POLYGON);
			glNormal3f(-1.0f, 0.0f, 0.0f);	// left face
			glVertex3f(-0.5f, 0.5f, 0.5f);	
			glVertex3f(-0.5f, 0.5f, -0.5f);
			glVertex3f(-0.5f, -0.5f, -0.5f);
			glVertex3f(-0.5f, -0.5f, 0.5f);
		glEnd();
		glBegin(GL_POLYGON);
			glNormal3f(0.0f, -1.0f, 0.0f);	// bottom face
			glVertex3f(-0.5f, -0.5f, 0.5f);
			glVertex3f(-0.5f, -0.5f, -0.5f);
			glVertex3f(0.5f, -0.5f, -0.5f);
			glVertex3f(0.5f, -0.5f, 0.5f);	
		glEnd();
		glBegin(GL_POLYGON);
			glNormal3f(0.0f, 0.0f, -1.0f);	// back face
			glVertex3f(0.5f, -0.5f, -0.5f);
			glVertex3f(-0.5f, -0.5f, -0.5f);
			glVertex3f(-0.5f, 0.5f, -0.5f);
			glVertex3f(0.5f, 0.5f, -0.5f);	
		glEnd();
	glPopMatrix();
}


// Render
// desc: handles drawing of scene
void Render()
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);		// clear screen and depth buffer
	glLoadIdentity();										// reset modelview matrix

	angle = angle + 0.1f;					// increase our rotation angle counter
	if (angle >= 360.0f)					
		angle = 0.0f;

	glTranslatef(0.0f, 0.0f, -3.0f);		// perform transformations
	glRotatef(angle, 1.0f, 0.0f, 0.0f);		// place cube at (0,-3) and rotate it
	glRotatef(angle, 0.0f, 1.0f, 0.0f);
	glRotatef(angle, 0.0f, 0.0f, 1.0f);

	DrawCube(0.0f, 0.0f, 0.0f);				// draw the transformed cube
	
	glFlush();

	SwapBuffers(g_HDC);			// bring backbuffer to foreground
}

// function to set the pixel format for the device context
void SetupPixelFormat(HDC hDC)
{
	int nPixelFormat;					// our pixel format index

	static PIXELFORMATDESCRIPTOR pfd = {
		sizeof(PIXELFORMATDESCRIPTOR),	// size of structure
		1,								// default version
		PFD_DRAW_TO_WINDOW |			// window drawing support
		PFD_SUPPORT_OPENGL |			// OpenGL support
		PFD_DOUBLEBUFFER,				// double buffering support
		PFD_TYPE_RGBA,					// RGBA color mode
		32,								// 32 bit color mode
		0, 0, 0, 0, 0, 0,				// ignore color bits, non-palettized mode
		0,								// no alpha buffer
		0,								// ignore shift bit
		0,								// no accumulation buffer
		0, 0, 0, 0,						// ignore accumulation bits
		16,								// 16 bit z-buffer size
		0,								// no stencil buffer
		0,								// no auxiliary buffer
		PFD_MAIN_PLANE,					// main drawing plane
		0,								// reserved
		0, 0, 0 };						// layer masks ignored

	nPixelFormat = ChoosePixelFormat(hDC, &pfd);	// choose best matching pixel format

	SetPixelFormat(hDC, nPixelFormat, &pfd);		// set pixel format to device context
}

// the Windows Procedure event handler
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	static HGLRC hRC;					// rendering context
	static HDC hDC;						// device context
	int width, height;					// window width and height

	switch(message)
	{
		case WM_CREATE:					// window is being created

			hDC = GetDC(hwnd);			// get current window's device context
			g_HDC = hDC;
			SetupPixelFormat(hDC);		// call our pixel format setup function

			// create rendering context and make it current
			hRC = wglCreateContext(hDC);
			wglMakeCurrent(hDC, hRC);

			return 0;
			break;

		case WM_CLOSE:					// windows is closing

			// deselect rendering context and delete it
			wglMakeCurrent(hDC, NULL);
			wglDeleteContext(hRC);

			// send WM_QUIT to message queue
			PostQuitMessage(0);

			return 0;
			break;

		case WM_SIZE:
			height = HIWORD(lParam);		// retrieve width and height
			width = LOWORD(lParam);

			if (height==0)					// don't want a divide by zero
			{
				height=1;					
			}

			glViewport(0, 0, width, height);		// reset the viewport to new dimensions
			glMatrixMode(GL_PROJECTION);			// set projection matrix current matrix
			glLoadIdentity();						// reset projection matrix

			// calculate aspect ratio of window
			gluPerspective(54.0f,(GLfloat)width/(GLfloat)height,1.0f,1000.0f);

			glMatrixMode(GL_MODELVIEW);				// set modelview matrix
			glLoadIdentity();						// reset modelview matrix

			return 0;
			break;

		default:
			break;
	}

	return (DefWindowProc(hwnd, message, wParam, lParam));
}

// the main windows entry point
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
	WNDCLASSEX windowClass;		// window class
	HWND	   hwnd;			// window handle
	MSG		   msg;				// message
	bool	   done;			// flag saying when our app is complete
	DWORD	   dwExStyle;						// Window Extended Style
	DWORD	   dwStyle;						// Window Style
	RECT	   windowRect;

	// temp var's
	int width = 800;
	int height = 600;
	int bits = 32;

	//fullScreen = TRUE;

	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

	// fill out the window class structure
	windowClass.cbSize			= sizeof(WNDCLASSEX);
	windowClass.style			= CS_HREDRAW | CS_VREDRAW;
	windowClass.lpfnWndProc		= WndProc;
	windowClass.cbClsExtra		= 0;
	windowClass.cbWndExtra		= 0;
	windowClass.hInstance		= hInstance;
	windowClass.hIcon			= LoadIcon(NULL, IDI_APPLICATION);	// default icon
	windowClass.hCursor			= LoadCursor(NULL, IDC_ARROW);		// default arrow
	windowClass.hbrBackground	= NULL;								// don't need background
	windowClass.lpszMenuName	= NULL;								// no menu
	windowClass.lpszClassName	= "MyClass";
	windowClass.hIconSm			= LoadIcon(NULL, IDI_WINLOGO);		// windows logo small icon

	// register the windows class
	if (!RegisterClassEx(&windowClass))
		return 0;

	if (fullScreen)								// fullscreen?
	{
		DEVMODE dmScreenSettings;					// device mode
		memset(&dmScreenSettings,0,sizeof(dmScreenSettings));
		dmScreenSettings.dmSize = sizeof(dmScreenSettings);	
		dmScreenSettings.dmPelsWidth = width;			// screen width
		dmScreenSettings.dmPelsHeight = height;			// screen height
		dmScreenSettings.dmBitsPerPel = bits;				// bits per pixel
		dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

		// 
		if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
		{
			// setting display mode failed, switch to windowed
			MessageBox(NULL, "Display mode failed", NULL, MB_OK);
			fullScreen=FALSE;	
		}
	}

	if (fullScreen)								// Are We Still In Fullscreen Mode?
	{
		dwExStyle=WS_EX_APPWINDOW;					// Window Extended Style
		dwStyle=WS_POPUP;						// Windows Style
		ShowCursor(FALSE);						// Hide Mouse Pointer
	}
	else
	{
		dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;			// Window Extended Style
		dwStyle=WS_OVERLAPPEDWINDOW;					// Windows Style
	}

	AdjustWindowRectEx(&windowRect, dwStyle, FALSE, dwExStyle);		// Adjust Window To True Requested Size

	// class registered, so now create our window
	hwnd = CreateWindowEx(NULL,									// extended style
						  "MyClass",							// class name
						  "Lighting Example 1: Rotating, Lit Cube",		// app name
						  dwStyle | WS_CLIPCHILDREN |
						  WS_CLIPSIBLINGS,
						  0, 0,								// x,y coordinate
						  windowRect.right - windowRect.left,
						  windowRect.bottom - windowRect.top, // width, height
						  NULL,									// handle to parent
						  NULL,									// handle to menu
						  hInstance,							// application instance
						  NULL);								// no extra params

	// check if window creation failed (hwnd would equal NULL)
	if (!hwnd)
		return 0;

	ShowWindow(hwnd, SW_SHOW);			// display the window
	UpdateWindow(hwnd);					// update the window

	done = false;						// intialize the loop condition variable
	Initialize();						// initialize OpenGL

	// main message loop
	while (!done)
	{
		PeekMessage(&msg, hwnd, NULL, NULL, PM_REMOVE);

		if (msg.message == WM_QUIT)		// do we receive a WM_QUIT message?
		{
			done = true;				// if so, time to quit the application
		}
		else
		{
			Render();

			TranslateMessage(&msg);		// translate and dispatch to event queue
			DispatchMessage(&msg);
		}
	}

	if (fullScreen)
	{
		ChangeDisplaySettings(NULL,0);					// If So Switch Back To The Desktop
		ShowCursor(TRUE);						// Show Mouse Pointer
	}

	return msg.wParam;
}