NeHe_002-004_画旋转的彩色三角形和矩形

这是第二到第四课的内容。主要介绍了怎样画出一个三角形和矩形，为他们添加色彩，然后添加语句使这两个图形旋转。

代码如下，在vs2008中调试通过。

[code]#include<windows.h>//vs2008,windows.h has glaut.h
#include<tchar.h>
#include <gl\gl.h>
#include <gl\glu.h>
#pragma comment(lib,"opengl32.lib")
#pragma comment(lib,"glu32.lib")

HGLRC           hRC=NULL;              // Permanent Rendering Context
HDC             hDC=NULL;              // Private GDI Device 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=FALSE;              // no 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
}//end of ReSizeGLScene

int InitGL(GLvoid)                  // All Setup For OpenGL Goes Here
{
glShadeModel(GL_SMOOTH);          // Enables Smooth Shading
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);      // Black Background
glClearDepth(1.0f);              // Depth Buffer Setup
glEnable(GL_DEPTH_TEST);          // Enables Depth Testing
glDepthFunc(GL_LEQUAL);              // The Type Of Depth Test To Do
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);            // Really Nice Perspective Calculations

return TRUE;                  // Initialization Went OK
}//end of InitGL

int DrawGLScene(GLvoid)                  // Here's Where We Do All The Drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);            // Clear The Screen And The Depth Buffer
glLoadIdentity();              // Reset The Current Modelview Matrix

//
//TODO:the code of openGL
//
glTranslatef(-1.5f,0.0f,-6.0f);      // Move Left 1.5 Units And Into The Screen 6.0
glBegin(GL_TRIANGLES);          // Drawing Using Triangles
glColor3f(1.0f,0.0f,0.0f);            // Set The Color To Red
glVertex3f( 0.0f, 1.0f, 0.0f);  // Top
glColor3f(0.0f,1.0f,0.0f);            // Set The Color To Green
glVertex3f(-1.0f,-1.0f, 0.0f);  // Bottom Left
glColor3f(0.0f,0.0f,1.0f);            // Set The Color To Blue
glVertex3f( 1.0f,-1.0f, 0.0f);  // Bottom Right
glEnd();
glTranslatef(3.0f,0.0f,0.0f);      // Move Right 3 Units
/*
*By drawing in a clockwise order, the square will be drawn as a back face.
*Meaning the side of the quad we see is actually the back.
*Objects drawn in a counter clockwise order will be facing us.
*Not important at the moment, but later on you will need to know this.
*/
//glColor3f(0.5f,0.0f,0.5f);            // Set The Color
glBegin(GL_QUADS);          // Draw A Quad
glVertex3f(-1.0f, 1.0f, 0.0f);  // Top Left
glVertex3f( 1.0f, 1.0f, 0.0f);  // Top Right
glVertex3f( 1.0f,-1.0f, 0.0f);  // Bottom Right
glVertex3f(-1.0f,-1.0f, 0.0f);  // Bottom Left
glEnd();              // Done Drawing The Quad
return TRUE;              // Keep Going
}//end of DrawGLScene

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,_T("Release Of DC And RC Failed."),_T("SHUTDOWN ERROR"),MB_OK | MB_ICONINFORMATION);
}
if (!wglDeleteContext(hRC))      // Are We Able To Delete The RC?
{
MessageBox(NULL,_T("Release Rendering Context Failed."),_T("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,_T("Release Device Context Failed."),_T("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,_T("Could Not Release hWnd."),_T("SHUTDOWN ERROR"),MB_OK | MB_ICONINFORMATION);
hWnd=NULL;              // Set hWnd To NULL
}
if (!UnregisterClass(_T("OpenGL"),hInstance))  // Are We Able To Unregister Class
{
MessageBox(NULL,_T("Could Not Unregister Class."),_T("SHUTDOWN ERROR"),MB_OK | MB_ICONINFORMATION);
hInstance=NULL;              // Set hInstance To NULL
}
}//end of KillGLWindow

BOOL CreateGLWindow(TCHAR * 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 Move, 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    = _T("OpenGL");      // Set The Class Name
if (!RegisterClass(&wc))          // Attempt To Register The Window Class
{
MessageBox(NULL,_T("Failed To Register The Window Class."),_T("ERROR"),MB_OK|MB_ICONEXCLAMATION);
return FALSE;              // Exit And 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 Run In A Window.
if (MessageBox(NULL,_T("The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?"),_T("NeHe GL"),MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
{
fullscreen=FALSE;  // Select Windowed Mode (Fullscreen=FALSE)
}
else
{
// Pop Up A Message Box Letting User Know The Program Is Closing.
MessageBox(NULL,_T("Program Will Now Close."),_T("ERROR"),MB_OK|MB_ICONSTOP);
return FALSE;      // Exit And 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
if (!(hWnd=CreateWindowEx(    dwExStyle,  // Extended Style For The Window
_T("OpenGL"),  // Class Name
title,      // Window Title
WS_CLIPSIBLINGS |            // Required Window Style
WS_CLIPCHILDREN |            // Required Window Style
dwStyle,  // Selected Window Style
0, 0,      // Window Position
WindowRect.right-WindowRect.left,    // Calculate Adjusted Window Width
WindowRect.bottom-WindowRect.top,    // Calculate Adjusted Window Height
NULL,      // No Parent Window
NULL,      // No Menu
hInstance,  // Instance
NULL)))      // Don't Pass Anything To WM_CREATE
{
KillGLWindow();              // Reset The Display
MessageBox(NULL,_T("Window Creation Error."),_T("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,_T("Can't Create A GL Device Context."),_T("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,_T("Can't Find A Suitable PixelFormat."),_T("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,_T("Can't Set The PixelFormat."),_T("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,_T("Can't Create A GL Rendering Context."),_T("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,_T("Can't Activate The GL Rendering Context."),_T("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,_T("Initialization Failed."),_T("ERROR"),MB_OK|MB_ICONEXCLAMATION);
return FALSE;              // Return FALSE
}
return TRUE;                  // Success
}//end of CreateGLWindow

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);
}//end of  WndProc

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,_T("Would You Like To Run In Fullscreen Mode?"),_T( "Start FullScreen?"),MB_YESNO|MB_ICONQUESTION)==IDNO)
{
fullscreen=FALSE;          // Windowed Mode
}
else
{
fullscreen=TRUE;
}
// Create Our OpenGL Window
if (!CreateGLWindow(_T("NeHe's OpenGL Framework"),640,480,16,fullscreen))
{
return 0;              // Quit If Window Was Not Created
}
while(!done)                  // Loop That Runs Until done=TRUE
{
if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))            // Is There A Message Waiting?
{
/*
*The first thing we have to do is check to see if any window messages are waiting.
*By using PeekMessage() we can check for messages without halting our program.
*A lot of programs use GetMessage(). It works fine, but with GetMessage()
*your program doesn't do anything until it receives a paint message or some other window message.
*/
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(_T("NeHe's OpenGL Framework"),640,480,16,fullscreen))
{
return 0;  // Quit If Window Was Not Created
}
}
}//else
}//while
// Shutdown
KillGLWindow();                  // Kill The Window
return (msg.wParam);              // Exit The Program
}//end of WinMain

[/code]

添加以下两段代码为这两个图形添加色彩，并使之绕某个坐标轴旋转。

代码一

[code]GLfloat        rtri;         // Angle For The Triangle ( NEW )
GLfloat        rquad;       // Angle For The Quad     ( NEW )

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

代码二[/code]

[code]int DrawGLScene(GLvoid)                   // Here's Where We Do All The Drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);      // Clear The Screen And The Depth Buffer
glLoadIdentity();                            // Reset The Current Modelview Matrix

//
//TODO:the code of openGL
//
glTranslatef(-1.5f,0.0f,-6.0f);            // Move Left 1.5 Units And Into The Screen 6.0

glRotatef(rtri,0.0f,1.0f,0.0f);                // Rotate The Triangle On The Y axis ( NEW )
glBegin(GL_TRIANGLES);                        // Drawing Using Triangles
glColor3f(1.0f,0.0f,0.0f);            // Set The Color To Red
glVertex3f( 0.0f, 1.0f, 0.0f);                // Top
glColor3f(0.0f,1.0f,0.0f);            // Set The Color To Green
glVertex3f(-1.0f,-1.0f, 0.0f);                // Bottom Left
glColor3f(0.0f,0.0f,1.0f);            // Set The Color To Blue
glVertex3f( 1.0f,-1.0f, 0.0f);                // Bottom Right
glEnd();

glLoadIdentity();                    // Reset The Current Modelview Matrix
glTranslatef(1.5f,0.0f,-6.0f);                // Move Right 1.5 Units And Into The Screen 6.0
glRotatef(rquad,1.0f,0.0f,0.0f);            // Rotate The Quad On The X axis ( NEW )
//glColor3f(0.5f,0.5f,1.0f);                // Set The Color To A Nice Blue Shade
glBegin(GL_QUADS);                    // Start Drawing A Quad
glVertex3f(-1.0f, 1.0f, 0.0f);            // Top Left Of The Quad
glVertex3f( 1.0f, 1.0f, 0.0f);            // Top Right Of The Quad
glVertex3f( 1.0f,-1.0f, 0.0f);            // Bottom Right Of The Quad
glVertex3f(-1.0f,-1.0f, 0.0f);            // Bottom Left Of The Quad
glEnd();                        // Done Drawing The Quad

rtri+=1.0f;                        // Increase The Rotation Variable For The Triangle ( NEW )
rquad-=1.0f;                        // Decrease The Rotation Variable For The Quad     ( NEW )

if(rtri>=360.0f)rtri-=360.0f;
if(rquad>=360.0f)rquad-=360.0f;

return TRUE;                        // Keep Going
}

[/code]

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