编程题目：利用Opengl绘制一个三角形。

编程题目：利用Opengl绘制一个三角形。

请给出详细的编程内容！答的好追加！

void CTes1View::DrawScene()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // 清除屏幕及深度缓存

SwapBuffers(wglGetCurrentDC());

glLoadIdentity(); // 重置

glTranslatef(-1.5f,0.0f,-6.0f); // 左移 1.5 单位，并移入屏幕 6.0

glBegin(GL_TRIANGLES); // 绘制三角形

glVertex3f(0.0f,0.0f,0.0f); // 上顶点

glVertex3f(0.0f, 0.0f,-1.0f); // 左下顶点

glVertex3f(0.0f,1.0f,0.0f); // 右下顶点

glEnd(); // 三角形绘制结束

glFinish();
}

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

//编译环境VS2005 选WIN32应用程序, 我从来不用MFC #include <GL/GL.h> #include <gl/GLU.h> #include <gl/GLAux.h> #include <math.h> #pragma comment(lib, "opengl32.lib") #pragma comment(lib, "glu32.lib") #pragma comment(lib, "glaux.lib") #define MAX_LOADSTRING 100 //定义递归调用阀值,即其中最小三角形边长 #define SIDELENGHT (0.05) // Global Variables: HINSTANCE hInst; // current instance TCHAR szTitle[MAX_LOADSTRING]; // The title bar text TCHAR szWindowClass[MAX_LOADSTRING]; // the main window class name //自定义全局变量 HGLRC g_hRC = NULL; //OpenGL 绘图上下文 HDC g_hDC = NULL; //设备上下文 HWND g_hWnd = NULL; //保存当前窗口句柄 //定义三角形顶点指针 typedef struct tagTRIANGLEPOINT { GLfloat tpPointX; GLfloat tpPointY; }TRIANGLEPOINT,*LTRIANGLEPOINT; //定义最外面大三角形三个点 TRIANGLEPOINT g_TrianglePoint[3] = {{0.0, 0.0}, {5.0, 0.0}, {2.5,2.5}}; // Forward declarations of functions included in this code module: ATOM MyRegisterClass(HINSTANCE hInstance); BOOL InitInstance(HINSTANCE, int); LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); INT_PTR CALLBACK About(HWND, UINT, WPARAM, LPARAM); //自定义函数 void EnableOpenGL(HWND hWnd); void SceneInit(); void SceneResizeViewport(); void DisableOpenGL(); void Display(); void DrawTriangle(LTRIANGLEPOINT pTrianglePoint, int iPointNum = 3); void DrawLargeTriangle(LTRIANGLEPOINT pTrianglePoint, int iPointNum); int APIENTRY _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow) { UNREFERENCED_PARAMETER(hPrevInstance); UNREFERENCED_PARAMETER(lpCmdLine); // TODO: Place code here. MSG msg; HACCEL hAccelTable; // Initialize global strings LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING); LoadString(hInstance, IDC_OPENGLTRIANGLE, szWindowClass, MAX_LOADSTRING); MyRegisterClass(hInstance); // Perform application initialization: if (!InitInstance (hInstance, nCmdShow)) { return FALSE; } EnableOpenGL(g_hWnd); SceneInit(); SceneResizeViewport(); hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_OPENGLTRIANGLE)); // Main message loop: ZeroMemory(&msg, sizeof(msg)); while ( msg.message != WM_QUIT ) { if (PeekMessage(&msg, NULL, 0U, 0U, PM_REMOVE)) { if(!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)) { TranslateMessage(&msg); DispatchMessage(&msg); } } else { Display(); SwapBuffers(g_hDC); } } DisableOpenGL(); return (int) msg.wParam; } // // FUNCTION: MyRegisterClass() // // PURPOSE: Registers the window class. // // COMMENTS: // // This function and its usage are only necessary if you want this code // to be compatible with Win32 systems prior to the 'RegisterClassEx' // function that was added to Windows 95. It is important to call this function // so that the application will get 'well formed' small icons associated // with it. // ATOM MyRegisterClass(HINSTANCE hInstance) { WNDCLASSEX wcex; wcex.cbSize = sizeof(WNDCLASSEX); wcex.style = CS_HREDRAW | CS_VREDRAW; wcex.lpfnWndProc = WndProc; wcex.cbClsExtra = 0; wcex.cbWndExtra = 0; wcex.hInstance = hInstance; wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_OPENGLTRIANGLE)); wcex.hCursor = LoadCursor(NULL, IDC_ARROW); wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1); wcex.lpszMenuName = MAKEINTRESOURCE(IDC_OPENGLTRIANGLE); wcex.lpszClassName = szWindowClass; wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL)); return RegisterClassEx(&wcex); } // // FUNCTION: InitInstance(HINSTANCE, int) // // PURPOSE: Saves instance handle and creates main window // // COMMENTS: // // In this function, we save the instance handle in a global variable and // create and display the main program window. // BOOL InitInstance(HINSTANCE hInstance, int nCmdShow) { HWND hWnd; hInst = hInstance; // Store instance handle in our global variable hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL); if (!hWnd) { return FALSE; } g_hWnd = hWnd; ShowWindow(hWnd, nCmdShow); UpdateWindow(hWnd); return TRUE; } // // FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM) // // PURPOSE: Processes messages for the main window. // // WM_COMMAND - process the application menu // WM_PAINT - Paint the main window // WM_DESTROY - post a quit message and return // // LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) { int wmId, wmEvent; PAINTSTRUCT ps; HDC hdc; switch (message) { case WM_COMMAND: wmId = LOWORd(wParam); wmEvent = HIWORd(wParam); // Parse the menu selections: switch (wmId) { case IDM_ABOUT: DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About); break; case IDM_EXIT: DestroyWindow(hWnd); break; default: return DefWindowProc(hWnd, message, wParam, lParam); } break; case WM_PAINT: hdc = BeginPaint(hWnd, &ps); // TODO: Add any drawing code here... EndPaint(hWnd, &ps); break; case WM_DESTROY: PostQuitMessage(0); break; default: return DefWindowProc(hWnd, message, wParam, lParam); } return 0; } // Message handler for about box. INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam) { UNREFERENCED_PARAMETER(lParam); switch (message) { case WM_INITDIALOG: return (INT_PTR)TRUE; case WM_COMMAND: if (LOWORd(wParam) == IDOK || LOWORd(wParam) == IDCANCEL) { EndDialog(hDlg, LOWORd(wParam)); return (INT_PTR)TRUE; } break; } return (INT_PTR)FALSE; } //初始化opengl void EnableOpenGL(HWND hWnd) { PIXELFORMATDESCRIPTOR pfd; int iFormat; g_hDC = GetDC(hWnd); ZeroMemory(&pfd, sizeof(pfd)); pfd.nSize = sizeof(pfd); pfd.nVersion = 1; pfd.dwFlags = PFD_DRAW_TO_WINDOW| PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER; pfd.iPixelType = PFD_TYPE_RGBA; pfd.cColorBits = 32; pfd.cDepthBits = 16; pfd.iLayerType = PFD_MAIN_PLANE; iFormat = ChoosePixelFormat( g_hDC, &pfd ); SetPixelFormat( g_hDC, iFormat, &pfd ); g_hRC = wglCreateContext(g_hDC); wglMakeCurrent( g_hDC, g_hRC); } //设置着色模式 void SceneInit() { glShadeModel(GL_SMOOTH); glClearColor(1.0, 1.0, 1.0, 0.5); glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); } //设置视口 void SceneResizeViewport() { RECT rect; int w,h; GLfloat aspect; GetClientRect( g_hWnd, &rect ); w = rect.right - rect.left; h =rect.bottom - rect.top; aspect = (GLfloat)w/ (GLfloat)h; glViewport(0,0,w,h);//设置视口 glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0.0, 5.0, 0.0, 5.0/aspect); } void DisableOpenGL(){ wglMakeCurrent(NULL, NULL); wglDeleteContext(g_hRC); ReleaseDC(g_hWnd, g_hDC); } void Display() { glClear(GL_COLOR_BUFFER_BIT); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); DrawLargeTriangle(g_TrianglePoint, 3); DrawTriangle(g_TrianglePoint, 3); glFlush(); } //画大三角形 void DrawLargeTriangle(LTRIANGLEPOINT pTrianglePoint, int iPointNum) { glBegin(GL_LINE_LOOP); for ( int i = 0; i < 3; ++i) { glColor3f(1.0,0.0,0.0); glVertex2f(pTrianglePoint[i].tpPointX,pTrianglePoint[i].tpPointY); } glEnd(); } //递归函数 void DrawTriangle(LTRIANGLEPOINT pTrianglePoint, int iPointNum) { //得到中间三角形的三个点 TRIANGLEPOINT trianglepoint[3]; for (int i = 0; i < 3; ++i) { if ( i == 2) { trianglepoint[i].tpPointX = (pTrianglePoint[i].tpPointX + pTrianglePoint[0].tpPointX) / 2; trianglepoint[i].tpPointY = (pTrianglePoint[i].tpPointY + pTrianglePoint[0].tpPointY) / 2; } else { trianglepoint[i].tpPointX = (pTrianglePoint[i].tpPointX + pTrianglePoint[i+1].tpPointX) / 2; trianglepoint[i].tpPointY = (pTrianglePoint[i].tpPointY + pTrianglePoint[i+1].tpPointY) / 2; } } glBegin(GL_LINE_LOOP); for ( int i = 0; i < 3; ++i) { glColor3f(1.0,0.0,0.0); glVertex2f(trianglepoint[i].tpPointX,trianglepoint[i].tpPointY); } glEnd(); //构建其它三角 TRIANGLEPOINT trianglepoint1[3]; TRIANGLEPOINT trianglepoint2[3]; TRIANGLEPOINT trianglepoint3[3]; ZeroMemory(&trianglepoint1, sizeof(trianglepoint1)); ZeroMemory(&trianglepoint2, sizeof(trianglepoint2)); ZeroMemory(&trianglepoint2, sizeof(trianglepoint2)); trianglepoint1[0] = pTrianglePoint[0]; trianglepoint1[1] = trianglepoint[0]; trianglepoint1[2] = trianglepoint[2]; trianglepoint2[0] = pTrianglePoint[1]; trianglepoint2[1] = trianglepoint[1]; trianglepoint2[2] = trianglepoint[0]; trianglepoint3[0] = pTrianglePoint[2]; trianglepoint3[1] = trianglepoint[2]; trianglepoint3[2] = trianglepoint[1]; //设定边界 if(pow(abs(trianglepoint1[0].tpPointX - trianglepoint1[1].tpPointX), 2) +pow(abs(trianglepoint1[0].tpPointY - trianglepoint1[1].tpPointY), 2) > SIDELENGHT) DrawTriangle(trianglepoint1, iPointNum); if(pow(trianglepoint2[0].tpPointX - trianglepoint2[1].tpPointX, 2) +pow(trianglepoint2[0].tpPointY - trianglepoint2[1].tpPointY, 2) > SIDELENGHT) DrawTriangle(trianglepoint2, iPointNum); if(pow(trianglepoint2[0].tpPointX - trianglepoint2[1].tpPointX, 2) +pow(trianglepoint2[0].tpPointY - trianglepoint2[1].tpPointY, 2) > SIDELENGHT) DrawTriangle(trianglepoint3, iPointNum);