《图形学》实验二：分形树
实验平台：
VC++6.0，OpenGL
实验内容：
先按某一方向画一条直线，然后在此线段上找到一系列节点，在每一节点处向左右偏转60各画一条分枝。节点位置和节点处所画分枝的长度的比值各按0.618分割。
编程要点：
1.递归调用
grow(x,y,length,fai)
2.结束条件：最短树枝
3.树枝数<10
实验结果：
代码：
1 #include <windows.h>
2 #include <gl/gl.h>
3 #include <stdio.h>
4
5 #define PI acos(-1.0)
6
7 //存储n边形的n个点坐标
8 float px[1000] = {0}; 9 float py[1000] = {0}; 10 int n; //n边形
11
12 void GetAllPoint(int n) //得到n边形n个点的坐标
13 { 14 float x,y; 15 float r = 0.8; //半径
16 float si = 2*PI/n; //360°/n
17 float angle = si/2; //开始度数
18 int pnum = 0; 19 while(angle<=2*PI){ 20 x = r*cos(angle); 21 y = r*sin(angle); 22 px[pnum] = x; 23 py[pnum++] = y; 24 angle = angle+si; 25 } 26 } 27
28 void ShowPic1(int n) //画出n边形的外边框
29 { 30 int i; 31 float x,y; 32 for(i=0;i<n;i++){ 33 x = px[i]; 34 y = py[i]; 35 glVertex2f(x,y); 36 } 37 } 38
39 void ShowPic2(int n) //画出n边形的中间连线
40 { 41 int i,j; 42 float x0,y0,x,y; 43 for(i=0;i<n;i++){ 44 x0 = px[i]; 45 y0 = py[i]; 46 for(j=0;j<n;j++){ 47 if(i==j) 48 continue; 49 glVertex2f(x0,y0); 50 x = px[j]; 51 y = py[j]; 52 glVertex2f(x,y); 53 } 54 } 55 } 56
57 LRESULT CALLBACK WindowProc(HWND, UINT, WPARAM, LPARAM); 58 void EnableOpenGL(HWND hwnd, HDC*, HGLRC*); 59 void DisableOpenGL(HWND, HDC, HGLRC); 60
61 int WINAPI WinMain(HINSTANCE hInstance, 62 HINSTANCE hPrevInstance, 63 LPSTR lpCmdLine, 64 int nCmdShow) 65 { 66 WNDCLASSEX wcex; 67 HWND hwnd; 68 HDC hDC; 69 HGLRC hRC; 70 MSG msg; 71 BOOL bQuit = FALSE; 72 float theta = 0.0f; 73
74 printf("请输入n (n边形)：\n"); 75 scanf("%d",&n); 76
77 GetAllPoint(n); //获取多边形全部的点
78
79 /* register window class */
80 wcex.cbSize = sizeof(WNDCLASSEX); 81 wcex.style = CS_OWNDC; 82 wcex.lpfnWndProc = WindowProc; 83 wcex.cbClsExtra = 0; 84 wcex.cbWndExtra = 0; 85 wcex.hInstance = hInstance; 86 wcex.hIcon = LoadIcon(NULL, IDI_APPLICATION); 87 wcex.hCursor = LoadCursor(NULL, IDC_ARROW); 88 wcex.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH); 89 wcex.lpszMenuName = NULL; 90 wcex.lpszClassName = "GLSample"; 91 wcex.hIconSm = LoadIcon(NULL, IDI_APPLICATION);; 92
93
94 if (!RegisterClassEx(&wcex)) 95 return 0; 96
97 /* create main window */
98 hwnd = CreateWindowEx(0, 99 "GLSample", 100 "钻石图案", 101 WS_OVERLAPPEDWINDOW, 102 CW_USEDEFAULT, 103 CW_USEDEFAULT, 104 700, 105 700, 106 NULL, 107 NULL, 108 hInstance, 109 NULL); 110
111 ShowWindow(hwnd, nCmdShow); 112
113 /* enable OpenGL for the window */
114 EnableOpenGL(hwnd, &hDC, &hRC); 115
116 /* program main loop */
117 while (!bQuit) 118 { 119 /* check for messages */
120 if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) 121 { 122 /* handle or dispatch messages */
123 if (msg.message == WM_QUIT) 124 { 125 bQuit = TRUE; 126 } 127 else
128 { 129 TranslateMessage(&msg); 130 DispatchMessage(&msg); 131 } 132 } 133 else
134 { 135 /* OpenGL animation code goes here */
136
137 glClearColor(0.0f, 0.0f, 0.0f, 0.0f); 138 glClear(GL_COLOR_BUFFER_BIT); 139
140 //glPushMatrix(); 141 //glRotatef(theta, 0.0f, 0.0f, 1.0f);
142
143 glBegin(GL_LINE_STRIP); 144 glColor3f(1.0f, 0.0f, 0.0f); //设置画笔颜色
145 ShowPic1(n); //输出n边形的外边框
146 glEnd(); 147
148 //printf("%d\n",pnum);
149
150 glBegin(GL_LINES); 151 ShowPic2(n); //画出n边形的中间连线
152 glEnd(); 153
154 glPopMatrix(); 155
156 SwapBuffers(hDC); 157
158 theta += 1.0f; 159 Sleep (1); 160 } 161 } 162
163 /* shutdown OpenGL */
164 DisableOpenGL(hwnd, hDC, hRC); 165
166 /* destroy the window explicitly */
167 DestroyWindow(hwnd); 168
169 return msg.wParam; 170 } 171
172 LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) 173 { 174 switch (uMsg) 175 { 176 case WM_CLOSE: 177 PostQuitMessage(0); 178 break; 179
180 case WM_DESTROY: 181 return 0; 182
183 case WM_KEYDOWN: 184 { 185 switch (wParam) 186 { 187 case VK_ESCAPE: 188 PostQuitMessage(0); 189 break; 190 } 191 } 192 break; 193
194 default: 195 return DefWindowProc(hwnd, uMsg, wParam, lParam); 196 } 197
198 return 0; 199 } 200
201 void EnableOpenGL(HWND hwnd, HDC* hDC, HGLRC* hRC) 202 { 203 PIXELFORMATDESCRIPTOR pfd; 204
205 int iFormat; 206
207 /* get the device context (DC) */
208 *hDC = GetDC(hwnd); 209
210 /* set the pixel format for the DC */
211 ZeroMemory(&pfd, sizeof(pfd)); 212
213 pfd.nSize = sizeof(pfd); 214 pfd.nVersion = 1; 215 pfd.dwFlags = PFD_DRAW_TO_WINDOW |
216 PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER; 217 pfd.iPixelType = PFD_TYPE_RGBA; 218 pfd.cColorBits = 24; 219 pfd.cDepthBits = 16; 220 pfd.iLayerType = PFD_MAIN_PLANE; 221
222 iFormat = ChoosePixelFormat(*hDC, &pfd); 223
224 SetPixelFormat(*hDC, iFormat, &pfd); 225
226 /* create and enable the render context (RC) */
227 *hRC = wglCreateContext(*hDC); 228
229 wglMakeCurrent(*hDC, *hRC); 230 } 231
232 void DisableOpenGL (HWND hwnd, HDC hDC, HGLRC hRC) 233 { 234 wglMakeCurrent(NULL, NULL); 235 wglDeleteContext(hRC); 236 ReleaseDC(hwnd, hDC); 237 }
Freecode : www.cnblogs.com/yym2013