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程序本身是想通过空格键打开或者关闭深度测试,来观察在立方体里的球体,但最后运行却看不到效果,这是为什么啊?源代码如下:
#include <windows.h> // standard Windows app include
#include <math.h>
#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; // true = fullscreen; false = windowed
bool keyPressed[256]; // holds true for keys that are pressed
bool cuttingPlane = true; // true: cutting plane is enabled
// Initialize
// desc: initializes OpenGL
void Initialize()
{
glEnable(GL_DEPTH_TEST); // enable the depth buffer
glEnable(GL_CULL_FACE); // cull hidden faces
glEnable(GL_LIGHTING); // enable lighting
glEnable(GL_LIGHT0); // enable light0
glEnable(GL_COLOR_MATERIAL); // set material to colors
glShadeModel(GL_SMOOTH); // enable smooth shading
glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // Clear background to black
}
// Render
// desc: handles drawing of scene
void Render()
{
// clear screen and depth buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
angle += 0.2f; // increase rotation angle
// move scene back and rotate about the y-axis
glTranslatef(0.0f, 0.0f, -100.0f);
// first draw the solid sphere inside the cube
glPushMatrix();
glRotatef(angle, 0.0f, 1.0f, 0.0f);
glColor3f(1.0f, 1.0f, 0.0f);
auxSolidSphere(5.0f);
glPopMatrix();
// second draw the solid cube
glPushMatrix();
glRotatef(angle, 1.0f, 0.0f, 0.0f);
//glRotatef(angle, 0.0f, 1.0f, 0.0f);
//glRotatef(angle, 0.0f, 0.0f, 1.0f);
// draw the cutting plane if cutting is enabled
// on one side of the cube
if (cuttingPlane)
{
glDrawBuffer(GL_NONE);
glBegin(GL_QUADS);
glVertex3f(-10.0f, -10.0f, 15.1f);
glVertex3f(10.0f, -10.0f, 15.1f);
glVertex3f(10.0f, 10.0f, 15.1f);
glVertex3f(-10.0f, 10.0f, 15.1f);
glEnd();
glDrawBuffer(GL_BACK);
}
glColor3f(0.2f, 0.4f, 0.6f);
auxSolidCube(30.0f);
glPopMatrix();
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;
case WM_KEYDOWN: // is a key pressed?
keyPressed[wParam] = true;
return 0;
break;
case WM_KEYUP:
keyPressed[wParam] = false;
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
"Depth Buffer Example 2: Cutting Plane", // 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
{
if (keyPressed[VK_ESCAPE])
done = true;
else
{
if (keyPressed[VK_SPACE])
cuttingPlane = !cuttingPlane;
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;
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发表于 2007-3-28 11:28:00
