学步园

今晚根据OpenGL Tutorial 教程Lesson 0，把书中代码实现了一下，结果程序运行无法全屏，

正确代码代码如下

#include <windows.h><br /> #include <gl/glu.h><br /> #include <gl/glut.h><br /> #include <gl/glaux.h><br /> HGLRC hRC = NULL;<br /> HDC hDC = NULL;<br /> HWND hWnd = NULL;<br /> HINSTANCE hInstance;<br /> bool keys[256];<br /> bool active = true;<br /> bool fullscreen = true;<br /> LRESULT CALLBACK WndProc(HWND hWnd, UINT, WPARAM, LPARAM);<br /> GLvoid ReSizeGLScene(GLsizei width, GLsizei height)<br /> {<br /> if (height == 0)<br /> {<br /> height = 1;<br /> }</p> <p> glViewport(0, 0, width, height);</p> <p> glMatrixMode(GL_PROJECTION);<br /> glLoadIdentity();</p> <p> gluPerspective(45.0f, (GLfloat)width / (GLfloat)height, 0.1f, 100.0f);<br /> glMatrixMode(GL_MODELVIEW);<br /> glLoadIdentity();<br /> }<br /> int InitGL(GLvoid)<br /> {<br /> glShadeModel(GL_SMOOTH);<br /> glClearColor(0.0f, 0.0f, 0.0f, 0.0f);<br /> glClearDepth(1.0f);<br /> glEnable(GL_DEPTH_TEST);<br /> glDepthFunc(GL_LEQUAL);<br /> glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);<br /> return true;<br /> }<br /> int DrawGLScene(GLvoid)<br /> {<br /> glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);<br /> glLoadIdentity();<br /> return true;<br /> }<br /> GLvoid KillGLWindow(GLvoid)<br /> {<br /> if (fullscreen)<br /> {<br /> ChangeDisplaySettings(NULL, 0);<br /> ShowCursor(true);<br /> }<br /> if (hRC)<br /> {<br /> if (!wglMakeCurrent(NULL, NULL))<br /> {<br /> MessageBox(NULL, "Release DC and RC failed", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);<br /> }<br /> if (!wglDeleteContext(hRC))<br /> {<br /> MessageBox(NULL, "Release Rendering Context Failed", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);<br /> }<br /> hRC = NULL;<br /> }<br /> if (hDC && !ReleaseDC(hWnd, hDC))<br /> {<br /> MessageBox(NULL, "Release Device Context Failed", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);<br /> hDC = NULL;<br /> }<br /> if (hWnd && !DestroyWindow(hWnd))<br /> {<br /> MessageBox(NULL, "Could Not Release hWnd", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);<br /> hWnd = NULL;<br /> }<br /> if (!UnregisterClass("OpenGL", hInstance))<br /> {<br /> MessageBox(NULL, "Could Not Unregister Class", "SHUTDOWN ERROR", MB_OK | MB_ICONINFORMATION);<br /> hInstance = NULL;<br /> }<br /> }<br /> BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag)<br /> {<br /> GLuint PixelFormat;<br /> WNDCLASS wc;<br /> DWORD dwExStyle;<br /> DWORD dwStyle;<br /> RECT WindowRect;<br /> WindowRect.left = (long)0;<br /> WindowRect.right = (long)width;<br /> WindowRect.top = (long)0;<br /> WindowRect.bottom = (long)height;<br /> fullscreen = fullscreenflag;<br /> hInstance = GetModuleHandle(NULL);<br /> wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;<br /> wc.lpfnWndProc = (WNDPROC)WndProc;<br /> wc.cbClsExtra = 0;<br /> wc.cbWndExtra = 0;<br /> wc.hInstance = hInstance;<br /> wc.hIcon = LoadIcon(NULL, IDI_WINLOGO);<br /> wc.hCursor = LoadCursor(NULL, IDC_ARROW);<br /> wc.hbrBackground = NULL;<br /> wc.lpszMenuName = NULL;<br /> wc.lpszClassName = "OpenGL";</p> <p> if (!RegisterClass(&wc))<br /> {<br /> MessageBox(NULL, "Failed To Register The Window Class", "ERROR", MB_OK | MB_ICONINFORMATION);<br /> return false;<br /> }<br /> if (fullscreen)<br /> {<br /> DEVMODE dmScreenSettings;<br /> memset(&dmScreenSettings, 0, sizeof(dmScreenSettings));<br /> dmScreenSettings.dmSize = sizeof(dmScreenSettings); // mistake dmScreenSettings.dmSize to dmScreenSettings.dmScal<br /> dmScreenSettings.dmPelsWidth = width;<br /> dmScreenSettings.dmPelsHeight = height;<br /> dmScreenSettings.dmBitsPerPel = bits;<br /> dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;<br /> if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)<br /> {<br /> if (MessageBox(NULL, "The Request Fullscreen Mode Is Not Supported By/nYour Video Card. Use Windowed mode Instead?", "NeHe GL", MB_YESNO | MB_ICONINFORMATION) == IDYES)<br /> {<br /> fullscreen = false;<br /> }<br /> else<br /> {<br /> MessageBox(NULL, "Program Will Now Close.", "ERROR", MB_OK | MB_ICONSTOP);<br /> return false;<br /> }<br /> }<br /> }<br /> if (fullscreen)<br /> {<br /> dwExStyle = WS_EX_APPWINDOW;<br /> dwStyle = WS_POPUP;<br /> ShowCursor(false);<br /> }<br /> else<br /> {<br /> dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;<br /> dwStyle = WS_OVERLAPPEDWINDOW;<br /> }<br /> AdjustWindowRectEx(&WindowRect, dwStyle, false, dwExStyle);</p> <p> if (!(hWnd = CreateWindowEx(dwExStyle,<br /> "OpenGL",<br /> title,<br /> dwStyle |<br /> WS_CLIPSIBLINGS |<br /> WS_CLIPCHILDREN,<br /> 0, 0,<br /> WindowRect.right- WindowRect.left,<br /> WindowRect.bottom - WindowRect.top,<br /> NULL,<br /> NULL,<br /> hInstance,<br /> NULL)))<br /> {<br /> KillGLWindow();<br /> MessageBox(NULL, "Window Creation Error", "ERROR", MB_OK | MB_ICONEXCLAMATION);<br /> return false;<br /> }<br /> static PIXELFORMATDESCRIPTOR pfd =<br /> {<br /> sizeof(PIXELFORMATDESCRIPTOR),<br /> 1,<br /> PFD_DRAW_TO_WINDOW |<br /> PFD_SUPPORT_OPENGL |<br /> PFD_DOUBLEBUFFER,<br /> PFD_TYPE_RGBA,<br /> bits,<br /> 0, 0, 0, 0, 0, 0,<br /> 0,<br /> 0,<br /> 0,<br /> 0, 0, 0, 0,<br /> 16,<br /> 0,<br /> 0,<br /> PFD_MAIN_PLANE,<br /> 0,<br /> 0, 0, 0<br /> };</p> <p> if (!(hDC = GetDC(hWnd)))<br /> {<br /> KillGLWindow();<br /> MessageBox(NULL, "Can't Create A GL Device Context", "ERROR", MB_OK | MB_ICONEXCLAMATION);<br /> return false;<br /> }<br /> if (!(PixelFormat = ChoosePixelFormat(hDC, &pfd)))<br /> {<br /> KillGLWindow();<br /> MessageBox(NULL, "Can't Find A Suitalbe PixelFormat.","ERROR",<br /> MB_OK | MB_ICONEXCLAMATION);<br /> return false;<br /> }<br /> if (!SetPixelFormat(hDC, PixelFormat, &pfd))<br /> {<br /> KillGLWindow();<br /> MessageBox(NULL, "Can't Set The PixelFormat.", "ERROR", MB_OK | MB_ICONEXCLAMATION);<br /> return false;<br /> }</p> <p> if (!(hRC = wglCreateContext(hDC)))<br /> {<br /> KillGLWindow();<br /> MessageBox(NULL, "Can't Create A GL Rendering Context.", "ERROR",<br /> MB_OK | MB_ICONEXCLAMATION);<br /> return false;<br /> }</p> <p> if (!wglMakeCurrent(hDC, hRC))<br /> {<br /> KillGLWindow();<br /> MessageBox(NULL, "Can't Active The GL Rendering Context.", "ERROR",<br /> MB_OK | MB_ICONEXCLAMATION);<br /> return false;<br /> }<br /> ShowWindow(hWnd, SW_SHOW);<br /> SetForegroundWindow(hWnd);<br /> SetFocus(hWnd);<br /> ReSizeGLScene(width, height);<br /> if (!InitGL())<br /> {<br /> KillGLWindow();<br /> MessageBox(NULL, "Initialization Failed.", "ERROR", MB_OK | MB_ICONEXCLAMATION);<br /> return false;<br /> }<br /> return true;<br /> }<br /> LRESULT CALLBACK WndProc(HWND hWnd,<br /> UINT uMsg,<br /> WPARAM wParam,<br /> LPARAM lParam)<br /> {<br /> switch (uMsg)<br /> {<br /> case WM_ACTIVATE:<br /> if (!HIWORD(wParam))<br /> {<br /> active = true;<br /> }<br /> else<br /> {<br /> active = false;<br /> }<br /> return 0;<br /> case WM_SYSCOMMAND:<br /> {<br /> switch (wParam)<br /> {<br /> case SC_SCREENSAVE:<br /> case SC_MONITORPOWER:<br /> return 0;<br /> }<br /> break;<br /> }<br /> case WM_CLOSE:<br /> {<br /> PostQuitMessage(0);<br /> return 0;<br /> }<br /> case WM_KEYDOWN:<br /> {<br /> keys[wParam] = true;<br /> return 0;<br /> }<br /> case WM_KEYUP:<br /> {<br /> keys[wParam] = false;<br /> return 0;<br /> }<br /> case WM_SIZE:<br /> {<br /> ReSizeGLScene(LOWORD(lParam), HIWORD(lParam));<br /> return 0;<br /> }<br /> }<br /> return DefWindowProc(hWnd, uMsg, wParam, lParam);<br /> }<br /> int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd )<br /> {<br /> MSG msg;<br /> BOOL done = false;<br /> if (MessageBox(NULL, "Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",<br /> MB_YESNO | MB_ICONQUESTION) == IDNO)<br /> {<br /> fullscreen = false;<br /> }</p> <p> if (!CreateGLWindow("NeHe's OpenGL Framework", 640, 480, 16, fullscreen))<br /> {<br /> return 0;<br /> }<br /> while (!done)<br /> {<br /> if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))<br /> {<br /> if (msg.message == WM_QUIT)<br /> {<br /> done = true;<br /> }<br /> else<br /> {<br /> TranslateMessage(&msg);<br /> DispatchMessage(&msg);<br /> }<br /> }<br /> else<br /> {<br /> if (active)<br /> {<br /> if (keys[VK_ESCAPE])<br /> {<br /> done = true;<br /> }<br /> else<br /> {<br /> DrawGLScene();<br /> SwapBuffers(hDC);<br /> }</p> <p> if (keys[VK_F1])<br /> {<br /> keys[VK_F1] = false;<br /> KillGLWindow();<br /> fullscreen = !fullscreen;<br /> if (!CreateGLWindow("NeHe's OpenGL Framwork", 640, 480, 16, fullscreen))<br /> {<br /> return 0;<br /> }<br /> }<br /> }<br /> }<br /> }<br /> KillGLWindow();<br /> return msg.wParam;<br />

最后发现原因是在113行把dmScreenSettings.dmSize写成dmScreenSettings.dmScal

郁闷~~~~

查阅MSDN，DEVMODE

The DEVMODE data structure contains information about the device
initialization and environment of a printer.

DEVMODE包含了设备初始化信息，在执行函数ChangeDisplaySettings，需要对dmScreenSetting进行初始化，由于没有dmScreenSetting.dmSize赋值导致dmScreenSetting的初始化无效，所以无法全屏，程序运行窗口如下所示：（具体原因任然不甚明了，明日继续研究~~~~睡觉去~~~~）