OpenGL 多边形

#include <windows.h> // Header File For Windows

#include <gl\gl.h> // Header File For The OpenGL32 Library

#include <gl\glu.h> // Header File For The GLu32 Library

#include <gl\glut.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

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

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

// Calculate The Aspect Ratio Of The Window
gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);

glMatrixMode(GL_MODELVIEW);
// Select The Modelview Matrix
glLoadIdentity();
// Reset The Modelview Matrix

}

int InitGL(GLvoid) // All Setup For OpenGL Goes Here

{
glShadeModel(GL_SMOOTH);
// Enable Smooth Shading
glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
// Black Background
glClearDepth(1.0f);
// Depth Buffer Setup
glEnable(GL_DEPTH_TEST);
// Enables Depth Testing
glDepthFunc(GL_LEQUAL);
// The Type Of Depth Testing To Do
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
// Really Nice Perspective Calculations
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);
glLoadIdentity();

glTranslatef(-1.5f, 0.0f, -6.0f);
glBegin(GL_TRIANGLES);
  glVertex3f(0.0f, 1.0f, 0.0f);
  glVertex3f(-1.0f, -1.0f, 0.0);
  glVertex3f(1.0f, -1.0f, 0.0f);
glEnd();

glTranslatef(3.0f, 0.0f, 0.0f);
glBegin(GL_QUADS);
 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();

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
}

}

/* 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
WindowRect.bottom=(long)height;
// Set Bottom Value To Requested Height

fullscreen=fullscreenflag;
// Set The Global Fullscreen Flag

hInstance
= GetModuleHandle(NULL); // Grab An Instance For Our Window
wc.style
= CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // Redraw On Size, And Own DC For Window.
wc.lpfnWndProc
= (WNDPROC) WndProc; // WndProc Handles Messages
wc.cbClsExtra
= 0; // No Extra Window Data
wc.cbWndExtra
= 0; // No Extra Window Data
wc.hInstance
= hInstance; // Set The Instance
wc.hIcon
= LoadIcon(NULL, IDI_WINLOGO); // Load The Default Icon
wc.hCursor
= LoadCursor(NULL, IDC_ARROW); // Load The Arrow Pointer
wc.hbrBackground
= NULL; // No Background Required For GL
wc.lpszMenuName
= NULL; // We Don't Want A Menu
wc.lpszClassName
= "OpenGL"; // Set The Class Name

if (!RegisterClass(&wc))
// Attempt To Register The Window Class
{
MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
// Return FALSE
}

if (fullscreen)
// Attempt Fullscreen Mode?
{
DEVMODE dmScreenSettings;
// Device Mode
memset(&dmScreenSettings,0,sizeof(dmScreenSettings));
// Makes Sure Memory's Cleared
dmScreenSettings.dmSize=sizeof(dmScreenSettings);
// Size Of The Devmode Structure
dmScreenSettings.dmPelsWidth
= width; // Selected Screen Width
dmScreenSettings.dmPelsHeight
= height; // Selected Screen Height
dmScreenSettings.dmBitsPerPel
= bits; // Selected Bits Per Pixel
dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

// Try To Set Selected Mode And Get Results.  NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.
if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)
{
// If The Mode Fails, Offer Two Options.  Quit Or Use Windowed Mode.
if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
{
fullscreen=FALSE;
// Windowed Mode Selected.  Fullscreen = FALSE
}
else
{
// Pop Up A Message Box Letting User Know The Program Is Closing.
MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);
return FALSE;
// Return 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

// Create The Window
if (!(hWnd=CreateWindowEx(
dwExStyle, // Extended Style For The Window
"OpenGL",
// Class Name
title,
// Window Title
dwStyle |
// Defined Window Style
WS_CLIPSIBLINGS |
// Required Window Style
WS_CLIPCHILDREN,
// Required Window Style
0, 0, // Window Position
WindowRect.right-WindowRect.left,
// Calculate Window Width
WindowRect.bottom-WindowRect.top,
// Calculate Window Height
NULL, // No Parent Window
NULL, // No Menu
hInstance,
// Instance
NULL)))
// Dont Pass Anything To WM_CREATE
{
KillGLWindow();
// Reset The Display
MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
// Return FALSE
}

static
PIXELFORMATDESCRIPTOR pfd= // pfd Tells Windows How We Want Things To Be
{
sizeof(PIXELFORMATDESCRIPTOR),
// Size Of This Pixel Format Descriptor
1, // Version Number
PFD_DRAW_TO_WINDOW |
// Format Must Support Window
PFD_SUPPORT_OPENGL |
// Format Must Support OpenGL
PFD_DOUBLEBUFFER,
// Must Support Double Buffering
PFD_TYPE_RGBA,
// Request An RGBA Format
bits, // Select Our Color Depth
0, 0, 0, 0, 0, 0,
// Color Bits Ignored
0, // No Alpha Buffer
0, // Shift Bit Ignored
0, // No Accumulation Buffer
0, 0, 0, 0,
// Accumulation Bits Ignored
16, // 16Bit Z-Buffer (Depth Buffer)  
0, // No Stencil Buffer
0, // No Auxiliary Buffer
PFD_MAIN_PLANE,
// Main Drawing Layer
0, // Reserved
0, 0, 0
// Layer Masks Ignored
};

if (!(hDC=GetDC(hWnd)))
// Did We Get A Device Context?
{
KillGLWindow();
// Reset The Display
MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
// Return FALSE
}

if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd)))
// Did Windows Find A Matching Pixel Format?
{
KillGLWindow();
// Reset The Display
MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
// Return FALSE
}

if(!SetPixelFormat(hDC,PixelFormat,&pfd))
// Are We Able To Set The Pixel Format?
{
KillGLWindow();
// Reset The Display
MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
// Return FALSE
}

if (!(hRC=wglCreateContext(hDC)))
// Are We Able To Get A Rendering Context?
{
KillGLWindow();
// Reset The Display
MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
// Return FALSE
}

if(!wglMakeCurrent(hDC,hRC))
// Try To Activate The Rendering Context
{
KillGLWindow();
// Reset The Display
MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
// Return FALSE
}

ShowWindow(hWnd,SW_SHOW);
// Show The Window
SetForegroundWindow(hWnd);
// Slightly Higher Priority
SetFocus(hWnd);
// Sets Keyboard Focus To The Window
ReSizeGLScene(width, height);
// Set Up Our Perspective GL Screen

if (!InitGL())
// Initialize Our Newly Created GL Window
{
KillGLWindow();
// Reset The Display
MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
// Return FALSE
}

return TRUE;
// Success

}

LRESULT CALLBACK WndProc( HWND
hWnd, // Handle For This Window
UINT uMsg,
// Message For This Window
WPARAM
wParam, // Additional Message Information
LPARAM
lParam) // Additional Message Information

{
switch (uMsg)
// Check For Windows Messages
{
case WM_ACTIVATE:
// Watch For Window Activate Message
{
if (!HIWORD(wParam))
// Check Minimization State
{
active=TRUE;
// Program Is Active
}
else
{
active=FALSE;
// Program Is No Longer Active
}

return 0;
// Return To The Message Loop
}

case WM_SYSCOMMAND:
// Intercept System Commands
{
switch (wParam)
// Check System Calls
{
case SC_SCREENSAVE:
// Screensaver Trying To Start?
case SC_MONITORPOWER:
// Monitor Trying To Enter Powersave?
return 0;
// Prevent From Happening
}
break;
// Exit
}

case WM_CLOSE:
// Did We Receive A Close Message?
{
PostQuitMessage(0);
// Send A Quit Message
return 0;
// Jump Back
}

case WM_KEYDOWN:
// Is A Key Being Held Down?
{
keys[wParam] = TRUE;
// If So, Mark It As TRUE
return 0;
// Jump Back
}

case WM_KEYUP:
// Has A Key Been Released?
{
keys[wParam] = FALSE;
// If So, Mark It As FALSE
return 0;
// Jump Back
}

case WM_SIZE:
// Resize The OpenGL Window
{
ReSizeGLScene(LOWORD(lParam),HIWORD(lParam));  // LoWord=Width, HiWord=Height
return 0;
// Jump Back
}
}

// Pass All Unhandled Messages To DefWindowProc
return DefWindowProc(hWnd,uMsg,wParam,lParam);

}

int WINAPI WinMain( HINSTANCE
hInstance, // Instance
HINSTANCE
hPrevInstance, // Previous Instance
LPSTR lpCmdLine,
// Command Line Parameters
int nCmdShow)
// Window Show State

{
MSG msg;
// Windows Message Structure
BOOL done=FALSE;
// Bool Variable To Exit Loop

// Ask The User Which Screen Mode They Prefer
if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO)
{
fullscreen=FALSE;
// Windowed Mode
}

// Create Our OpenGL Window
if (!CreateGLWindow("NeHe's OpenGL Framework",640,480,16,fullscreen))
{
return 0;
// Quit If Window Was Not Created
}

while(!done)
// Loop That Runs While done=FALSE
{
if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))
// Is There A Message Waiting?
{
if (msg.message==WM_QUIT)
// Have We Received A Quit Message?
{
done=TRUE;
// If So done=TRUE
}
else // If Not, Deal With Window Messages
{
TranslateMessage(&msg);
// Translate The Message
DispatchMessage(&msg);
// Dispatch The Message
}
}
else // If There Are No Messages
{
// Draw The Scene.  Watch For ESC Key And Quit Messages From DrawGLScene()
if (active)
// Program Active?
{
if (keys[VK_ESCAPE])
// Was ESC Pressed?
{
done=TRUE;
// ESC Signalled A Quit
}
else // Not Time To Quit, Update Screen
{
DrawGLScene();
// Draw The Scene
SwapBuffers(hDC);
// Swap Buffers (Double Buffering)
}
}

if (keys[VK_F1])
// Is F1 Being Pressed?
{
keys[VK_F1]=FALSE;
// If So Make Key FALSE
KillGLWindow();
// Kill Our Current Window
fullscreen=!fullscreen;
// Toggle Fullscreen / Windowed Mode
// Recreate Our OpenGL Window
if (!CreateGLWindow("NeHe's 第一个多边形程序",640,480,16,fullscreen))
{
return 0;
// Quit If Window Was Not Created
}
}
}
}

// Shutdown
KillGLWindow();
// Kill The Window
return (msg.wParam);
// Exit The Program

}