NeHe的OpenGl教程 - 前5课总结

NeHe 的 OpenGL 教程浅显易懂，每行都有注释，适合入门学习用。不过，要想让教程中的程序运行在我的电脑上，需要做一些小小的设置

我的电脑的软件配置：Windows XP Professional + Visual C++ 2008 Express

1. “项目属性”的 Configuration Properties 选项卡：Character Set
NeHe 教程用的全是 C-sytle null terminated string。所以我们要根据自己的项目的特点做相应设置。我的程序使用的都是UNICODE字符串，所以设置为 Use UNICODE Character Set

2. “Linker” -> “Input”选项卡：Additional Dependencies 需要添加两行

"$(WindowsSdkDir)Lib\glu32.lib"
"$(WindowsSdkDir)Lib\opengl32.lib"

3. 原教程中的代码：#include <glaux.h> 在网上很难找，于是去掉了。反正只要不用里面的代码就OK

然后就可以让下面的代码运行了：

#include <windows.h>
#include <math.h>
#include <gl\gl.h>
#include <gl\glu.h>
// global variable
HDC        g_hDC  = NULL;
HGLRC      g_hRC  = NULL;
HWND       g_hWnd = NULL;
HINSTANCE  g_hIns = NULL;
BOOL       g_pKeys[256]  = {0};
BOOL       g_bActive     = TRUE;
BOOL       g_bFullScreen = TRUE;
GLfloat    g_fAngle4Tri  = 0.0f;
GLfloat    g_fAngle4Quad = 0.0f;
LPCTSTR    g_lpszWndClass = TEXT("OpenGL");
const float kRotateSpeed = 0.001f;
const float kRadius = 3.0f;
const DWORD kStartTime = GetTickCount();
GLvoid ResizeGLWnd(GLsizei nWidth, GLsizei nHeight)
{
	if(nHeight == 0)
	{
		nHeight = 1;
	}
	glViewport(0, 0, nWidth, nHeight);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(45.0f, (GLfloat)nWidth/(GLfloat)nHeight, 0.1f, 100.0f);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}
GLvoid KillGLWnd()
{
	if(g_bFullScreen)
	{
		ChangeDisplaySettings(NULL, 0);
		ShowCursor(TRUE);
	}
	if(g_hRC)
	{
		if(!wglMakeCurrent(NULL, 0))
		{
			MessageBox(g_hWnd, TEXT("Desktop cannot be showed properly."), TEXT("SHUTDOWN ERROR"), MB_OK | MB_ICONINFORMATION);
		}
		if(!wglDeleteContext(g_hRC))
		{
			MessageBox(g_hWnd, TEXT("OpenGL rendering context cannot be released"), TEXT("SHUTDOWN ERROR"), MB_OK | MB_ICONINFORMATION);
		}
		g_hRC = NULL;
	}
	if(g_hDC && !ReleaseDC(g_hWnd, g_hDC))
	{
		MessageBox(g_hWnd, TEXT("Windows device context cannot be released"), TEXT("SHUTDOWN ERROR"), MB_OK | MB_ICONINFORMATION);
		g_hDC = NULL;
	}
	if(g_hWnd && !DestroyWindow(g_hWnd))
	{
		MessageBox(g_hWnd, TEXT("Windows cannot be destroyed"), TEXT("SHUTDOWN ERROR"), MB_OK | MB_ICONINFORMATION);
		g_hWnd = NULL;
	}
	if(!UnregisterClass(g_lpszWndClass, g_hIns))
	{
		MessageBox(g_hWnd, TEXT("Windows class unregistering failed"), TEXT("SHUTDOWN ERROR"), MB_OK | MB_ICONINFORMATION);
		g_hIns = NULL;
	}
}
int InitOpenGL()
{
	glShadeModel(GL_SMOOTH);
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	glClearDepth(1.0f);
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LEQUAL);
	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
	return TRUE;
}
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
BOOL CreateGLWnd(PTSTR lpTitle, int nWidth, int nHeight, int nBits, bool bFullScreen)
{
	GLuint nPixelFormat;
	WNDCLASS wc;
	DWORD dwStyle, dwExStyle;
	RECT WndRect;
	WndRect.left   = (long)0;
	WndRect.right  = (long)nWidth;
	WndRect.top    = (long)0;
	WndRect.bottom = (long)nHeight;
	g_bFullScreen = bFullScreen;
	g_hIns = GetModuleHandle(NULL);
	wc.style       = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
	wc.lpfnWndProc = (WNDPROC)WndProc;
	wc.cbClsExtra  = 0;
	wc.cbWndExtra  = 0;
	wc.hInstance   = g_hIns;
	wc.hIcon       = LoadIcon(NULL, IDI_WINLOGO);
	wc.hCursor     = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = NULL;
	wc.lpszMenuName  = NULL;
	wc.lpszClassName = g_lpszWndClass;
	if(!RegisterClass(&wc))
	{
		MessageBox(NULL, TEXT("Register of window class failed"), TEXT("CREATE ERROR"), MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}
	if(g_bFullScreen)
	{
		DEVMODE dmScreenSettings;
		memset(&dmScreenSettings, 0, sizeof(dmScreenSettings));
		dmScreenSettings.dmSize = sizeof(dmScreenSettings);
		dmScreenSettings.dmPelsWidth = nWidth;
		dmScreenSettings.dmPelsHeight = nHeight;
		dmScreenSettings.dmBitsPerPel = nBits;
		dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;
		if(ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN))
		{
			if (MessageBox(NULL,
				TEXT("The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?"),
				TEXT("NeHe GL"),
				MB_YESNO | MB_ICONEXCLAMATION)
				== IDYES)
			{
				g_bFullScreen = FALSE;		// Windowed Mode Selected.  Fullscreen = FALSE
			}
			else
			{
				// Pop Up A Message Box Letting User Know The Program Is Closing.
				MessageBox(NULL, TEXT("Program Will Now Close."),TEXT("ERROR"), MB_OK | MB_ICONSTOP);
				return FALSE;									// Return FALSE
			}
		}
	}
	if(g_bFullScreen)
	{
		dwExStyle = WS_EX_APPWINDOW;
		dwStyle   = WS_POPUP;
		ShowCursor(FALSE);
	}
	else
	{
		dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;
		dwStyle   = WS_OVERLAPPEDWINDOW;
	}
	AdjustWindowRectEx(&WndRect, dwStyle, FALSE, dwExStyle);
	if(!(g_hWnd = CreateWindowEx(dwExStyle,
		g_lpszWndClass,
		lpTitle,
		dwStyle | WS_CLIPSIBLINGS | WS_CLIPCHILDREN,
		0, 0,
		WndRect.right - WndRect.left,
		WndRect.bottom - WndRect.top,
		NULL,
		NULL,
		g_hIns,
		NULL)))
	{
		KillGLWnd();
		MessageBox(NULL, TEXT("Window Creation Error."),TEXT("ERROR"), MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}
	static	PIXELFORMATDESCRIPTOR pfd = 
	{
		sizeof(PIXELFORMATDESCRIPTOR),
		1,
		PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER,
		PFD_TYPE_RGBA,
		nBits,
		0,0,0,0,0,0,
		0,
		0,
		0,
		0,0,0,0,
		16,
		0,
		0,
		PFD_MAIN_PLANE,
		0,
		0,0,0
	};
	if(!(g_hDC = GetDC(g_hWnd)))
	{
		KillGLWnd();
		MessageBox(NULL, TEXT("Can't Create A GL Device Context."), TEXT("ERROR"), MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}
	if(!(nPixelFormat = ChoosePixelFormat(g_hDC, &pfd)))
	{
		KillGLWnd();
		MessageBox(NULL, TEXT("Can't find proper pixel format."), TEXT("ERROR"), MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}
	if(!SetPixelFormat(g_hDC, nPixelFormat, &pfd))
	{
		KillGLWnd();
		MessageBox(NULL, TEXT("Can't Set The PixelFormat."), TEXT("ERROR"),MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}
	if (!(g_hRC = wglCreateContext(g_hDC)))
	{
		KillGLWnd();
		MessageBox(NULL, TEXT("Can't Create A GL Rendering Context."), TEXT("ERROR"),MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}
	
	if(!wglMakeCurrent(g_hDC, g_hRC))
	{
		KillGLWnd();
		MessageBox(NULL, TEXT("Can't Activate The GL Rendering Context."), TEXT("ERROR"),MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}
	ShowWindow(g_hWnd, SW_SHOW);
	SetForegroundWindow(g_hWnd);
	SetFocus(g_hWnd);
	ResizeGLWnd(nWidth, nHeight);
	if(!InitOpenGL())
	{
		KillGLWnd();
		MessageBox(NULL, TEXT("Initialization Failed."), TEXT("ERROR"),MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}
}
int DrawScene()
{
	const GLfloat kDistanceZ = -15.0f;
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();
	// triangle
	glTranslatef(0.0f, -2.0f, kDistanceZ);
	glRotatef(g_fAngle4Tri, 0.0f, 1.0f, 0.0f);
	glBegin(GL_TRIANGLES);
	glColor3f(1.0f, 0.0f, 0.0f);
	glVertex3f(0.0f, 1.0f, 0.0f);
	glColor3f(0.0f, 1.0f, 0.0f);
	glVertex3f(-1.0f, -1.0f, 1.0f);
	glColor3f(0.0f, 0.0f, 1.0f);
	glVertex3f(1.0f, -1.0f, 1.0f);
	glColor3f(1.0f, 0.0f, 0.0f);
	glVertex3f(0.0f, 1.0f, 0.0f);
	glColor3f(0.0f, 0.0f, 1.0f);
	glVertex3f(1.0f, -1.0f, -1.0f);
	glColor3f(0.0f, 1.0f, 0.0f);
	glVertex3f(-1.0f, -1.0f, -1.0f);
	
	glColor3f(0.0f, 0.0f, 1.0f);
	glVertex3f(1.0f, -1.0f, 1.0f);
	glVertex3f(1.0f, -1.0f, -1.0f);
	glColor3f(0.0f, 1.0f, 0.0f);
	glVertex3f(-1.0f, -1.0f, -1.0f);
	glColor3f(0.0f, 1.0f, 0.0f);
	glVertex3f(-1.0f, -1.0f, -1.0f);
	glVertex3f(-1.0f, -1.0f, 1.0f);
	glColor3f(0.0f, 0.0f, 1.0f);
	glVertex3f(1.0f, -1.0f, 1.0f);
	glEnd();
	glLoadIdentity();
	// square
	DWORD dwDeltaTime = GetTickCount() - kStartTime;
	GLfloat fNewX = kRadius * cos(dwDeltaTime * kRotateSpeed);
	GLfloat fNewZ = kRadius * sin(dwDeltaTime * kRotateSpeed);
	glTranslatef(fNewX, -2.0f, fNewZ + kDistanceZ);
	glRotatef(g_fAngle4Quad, 0.0f, 1.0f, 0.0f);
	glBegin(GL_QUADS);
	glColor3f(0.0f, 1.0f, 0.0f);
	glVertex3f(1.0f, 1.0f, 0.0f);
	glVertex3f(-1.0f, 1.0f, 0.0f);
	glVertex3f(-1.0f, -1.0f, 0.0f);
	glVertex3f(1.0f, -1.0f, 0.0f);
	glEnd();
	g_fAngle4Tri  += 2.0f;
	g_fAngle4Quad += 20.0f;
	return TRUE;
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
	switch (uMsg)
	{
	case WM_ACTIVATE:
		g_bActive = !HIWORD(wParam) ? TRUE : FALSE;
		return 0;
	case WM_SYSCOMMAND:
		switch (wParam)
		{
		case SC_SCREENSAVE:
		case SC_MONITORPOWER:
			return 0;
		}
		break;
	case WM_CLOSE:
		PostQuitMessage(0);
		return 0;
	case WM_KEYDOWN:
		g_pKeys[wParam] = TRUE;
		return 0;
	case WM_KEYUP:
		g_pKeys[wParam] = FALSE;
		return 0;
	case WM_SIZE:
		ResizeGLWnd(LOWORD(lParam), HIWORD(lParam));
		return 0;
	}
	return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpCmdLine, int nCmdShow)
{
	MSG msg;
	BOOL bDone = FALSE;
	
	// Ask The User Which Screen Mode They Prefer
	if (MessageBox(NULL, TEXT("Would You Like To Run In Fullscreen Mode?"), TEXT("Start FullScreen?"), MB_YESNO | MB_ICONQUESTION) == IDNO)
	{
		g_bFullScreen = FALSE;
	}
	if (!CreateGLWnd(TEXT("NeHe's Rotation Tutorial"), 640, 480, 16, g_bFullScreen))
	{
		return 0;
	}
	
	while(!bDone)
	{
		if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
		{
			if (msg.message == WM_QUIT)
			{
				bDone = TRUE;
			}
			else
			{
				TranslateMessage(&msg);
				DispatchMessage(&msg);
			}
		}
		else
		{
			if ((g_bActive && !DrawScene()) || g_pKeys[VK_ESCAPE])
			{
				bDone = TRUE;
			}
			else
			{
				SwapBuffers(g_hDC);
			}
			if (g_pKeys[VK_F1])
			{
				g_pKeys[VK_F1] = FALSE;
				KillGLWnd();
				g_bFullScreen = !g_bFullScreen;
				if (!CreateGLWnd(TEXT("NeHe's Rotation Tutorial"), 640, 480, 16, g_bFullScreen))
				{
					return 0;
				}
			}
		}
	}
	KillGLWnd();
	return (msg.wParam);
}

显示效果如下图：