计算机图形学实验二 DAA与Bresham以及中点圆

实验二：直线与画圆算法
实验目的：理解光栅化，掌握几何数据如何经过一系列变换后转化为像素从而呈现在显示设备上。
基本要求：
 实现 DDA 和 Bresenham 画线算法
 实现画圆算法
 请勿直接调用 OpenGL 库中提供的绘制线段和圆的函数，需手动模拟如何通过绘制像素来显示几何图形，效果可参考下图。（界面显示的是“虚拟的像素”）
 可通过交互操作来确定线段的起点和终点。
实现：
  1 #include<GL/glut.h>
  2 #define EXIT_SUCCESS 0
  3 #include<stdio.h>
  4 #include<math.h>
  5 // later Edition
  6 int MODE = 0;          // 模式代码：0-DAA算法，1-Bresenham算法，2-中点圆算法
  7 bool mouseLeftDown;     // 实时记录鼠标左键状态
  8 bool mouseRightDown;    // 实时记录鼠标左键状态
  9 float mouseX, mouseY;   // 实时记录鼠标位置，与下一次鼠标位置之间形成微分
 10 
 11 int startX=0, startY=0, endX=0, endY=0;
 12 int start[2] = { 0 };
 13 int end[2] = { 0 };
 14 float red=1.0,green=1.0, blue=0.0;
 15 float PI = 3.415926535;
 16 
 17 int arr[500][500];
 18 
 19 void init(void)
 20 {
 21     //glClearColor(0.0, 0.0, 0.0, 0.0);/* select clearing color  */   // 设置背景颜色为黑色
 22     //glMatrixMode(GL_MODELVIEW);                   
 23     glClearColor(0.0, 0.0, 0.0, 0.0); /* white background */
 24     glColor3f(1.0, 0.0, 0.0); /* draw in red */
 25 
 26     /* set up viewing: */
 27     /* 500 x 500 window with origin lower left */
 28 
 29     glMatrixMode(GL_PROJECTION);
 30     glLoadIdentity();
 31     gluOrtho2D(0.0, 500.0, 0.0, 500.0);
 32     glMatrixMode(GL_MODELVIEW);
 33 }
 34 
 35 
 36 
 37 
 38 #define RED 1233
 39 #define BLUE 1234
 40 #define GREEN 1235
 41 #define WHITE 12366
 42 #define YELLOW 12367
 43 #define DAA_LINE 12368
 44 #define BRES_LINE 12369
 45 #define CIRCLE 12370
 46 void processMenuEvents(int option) {
 47     //option，就是传递过来的value的值。
 48     switch (option) {
 49     case RED:
 50         red = 1.0;
 51         green = 0.0;
 52         blue = 0.0; break;
 53     case GREEN:
 54         red = 0.0;
 55         green = 1.0;
 56         blue = 0.0; break;
 57     case BLUE:
 58         red = 0.0;
 59         green = 0.0;
 60         blue = 1.0; break;
 61     case WHITE:
 62         red = 1.0;
 63         green = 1.0;
 64         blue = 1.0; break;
 65     case YELLOW:
 66         red = 1.0;
 67         green = 1.0;
 68         blue = 0.0;break;
 69     case DAA_LINE:
 70         MODE = 0;break;
 71     case BRES_LINE:
 72         MODE = 1;break;
 73     case CIRCLE:
 74         MODE = 2;break;
 75     }
 76 }
 77 void createGLUTMenus() {
 78 
 79     int menu;
 80 
 81     // 创建菜单并告诉GLUT，processMenuEvents处理菜单事件。
 82     menu = glutCreateMenu(processMenuEvents);
 83 
 84     //给菜单增加条目
 85     glutAddMenuEntry("红色", RED);
 86     glutAddMenuEntry("蓝色", BLUE);
 87     glutAddMenuEntry("绿色", GREEN);
 88     glutAddMenuEntry("白色", WHITE);
 89     glutAddMenuEntry("黄色", YELLOW);
 90     glutAddMenuEntry("DAA_LINE", DAA_LINE);
 91     glutAddMenuEntry("BRES_LINE", BRES_LINE);
 92     glutAddMenuEntry("CIRCLE_SCAN", CIRCLE);
 93 
 94     // 把菜单和鼠标右键关联起来。
 95     glutAttachMenu(GLUT_RIGHT_BUTTON);
 96 }
 97 
 98 void DAA_alogrithm(int x0, int y0, int x1, int y1) {
 99     int x;
100     float dx, dy, y, k;
101     dx = x1 - x0,dy = y1 - y0; 
102     k = dy / dx, y = y0;
103     glPointSize(5.0);
104 
105     glBegin(GL_POINTS);
106     
107     for (x = x0;x <= x1;x++) {
108         
109         glVertex2d(x, int(y + 0.5));
110         y = y + k;
111     }
112     glEnd();
113 }
114 void y_DAA_alogrithm(int x0, int y0, int x1, int y1) {
115     int y;
116     float dx, dy, x, k;
117     dx = x1 - x0, dy = y1 - y0;
118     k = dx / dy, x = x0;
119     glPointSize(5.0);
120 
121     glBegin(GL_POINTS);
122 
123     for (y = y0;y <= y1;y++) {
124 
125         glVertex2d(int(x + 0.5),y );
126         x = x + k;
127     }
128     glEnd();
129 }
130 void Bresenham(int x0, int y0, int x1, int y1) {
131     bool is_nagetive_k = false;
132     if ((y1 - y0) * (x1 - x0) < 0) {
133         y1 *= -1, y0 *= -1;
134         is_nagetive_k = true;
135     }
136     int x, y, dx, dy, e;
137     dx = x1 - x0, dy = y1 - y0,e=-dx;
138     x = x0;y = y0;
139     glPointSize(5.0);
140 
141     glBegin(GL_POINTS);
142     for (int i = 0;i < dx;i++) {
143         if (!is_nagetive_k)glVertex2d(x, y);else {
144             glVertex2d(x, -y);
145         }
146         x++, e = e + 2 * dy; 
147         if (e >= 0)y++, e = e - 2 * dx;
148     }
149     glEnd();
150 }
151 void y_Bresenham(int x0, int y0, int x1, int y1) {
152     bool is_nagetive_k = false;
153     if ((y1 - y0) * (x1 - x0) < 0) {
154         y1 *= -1;y0 *= -1;
155         is_nagetive_k = true;
156     }
157 
158     int x, y, dx, dy, e;
159     dx = x1 - x0, dy = y1 - y0, e = -dy;
160     x = x0;y = y0;
161     glPointSize(5.0);
162 
163     glBegin(GL_POINTS);
164     for (int i = 0;i < dy;i++) {
165         if (!is_nagetive_k)glVertex2d(x, y);else {
166             glVertex2d(x, -y);
167         }
168         y++, e = e + 2 * dx;
169         if (e >= 0)x++, e = e - 2 * dy;
170     }
171     glEnd();
172 }
173 void circlePoints(int x,int y) {
174     glPointSize(5.0);
175     glBegin(GL_POINTS);
176     glVertex2d(x,y);glVertex2d(y,x);
177     glVertex2d(-x,y);glVertex2d(-y,x);
178     glVertex2d(x,-y);glVertex2d(y,-x);
179     glVertex2d(-x,-y);glVertex2d(-y,-x);
180     glEnd();
181 }
182 void mindCircle(int r) {
183     int x, y;
184     float d;
185     x = 0;y = r; d = 1.25 - r;
186     circlePoints(x, y);
187     while (x <= y) {
188         if (d < 0) {
189             d += 2 * x + 3;
190         }
191         else {
192             d += 2 * (x - y) + 5;y--;
193         }
194         x++;
195         circlePoints(x, y);
196     }
197 }
198 void display(void)
199 {
200     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
201     glColor3f(red, green, blue);
202     glLoadIdentity();
203 
204 
205    
206 
207     if (MODE == 0) {
208         if (abs(startY - endY) > abs(startX - endX)) {
209             if (startY > endY) {
210                 y_DAA_alogrithm(endX, endY,startX, startY);
211             }
212             else {
213                 y_DAA_alogrithm(startX, startY, endX, endY);
214             }
215         }
216         else {
217             if (startX > endX) {
218                 DAA_alogrithm(endX, endY, startX, startY);
219             }
220             else {
221                 DAA_alogrithm(startX, startY, endX, endY);
222             }
223         }
224     }
225     else if (MODE == 1) {
226 
227         if (startX > endX) {
228             if (abs(startY - endY) > abs(startX - endX))y_Bresenham(endX, endY, startX, startY);
229             else Bresenham(endX, endY, startX, startY);
230         }
231         else {
232             if(abs(startY - endY) > abs(startX - endX))y_Bresenham(startX, startY, endX, endY);
233             else Bresenham(startX, startY, endX, endY);
234         }
235     
236     }
237     else if(MODE==2){
238         glPushMatrix();
239         glTranslated(startX, startY, 0);
240         mindCircle(int(pow((startX - endX) * (startX - endX) + (startY - endY) * (startY - endY), 0.5)));
241         glTranslated(-endX, -endY, 0);
242         glPopMatrix();
243     }
244     
245     
246     
247     
248     /*
249     glBegin(GL_LINES);
250 
251     glVertex2d(startX, startY);glVertex2d(endX, endY);
252 
253     glEnd();
254 
255     */
256     /*
257     glPointSize(10.0);
258     for (int i = 0;i < 500;i++) {
259         glVertex2d(100, i);
260         glVertex2d(i, 100);
261         glVertex2d(i, i);
262 
263     }
264     glEnd();
265     */
266     
267     glutSwapBuffers();
268 }
269 int saveStack = 0;
270 int firstSaveFlag = -1;
271 void keyboard(unsigned char key, int x, int y)
272 
273 {
274     switch (key) {
275         case 'q':case 'Q':
276             exit(EXIT_SUCCESS);
277             break;
278     }    
279 }
280 int ww, hh;
281 
282 void mouse_process(int button, int state, int x, int y)
283 {
284     mouseX = x;
285     mouseY = y;
286     printf("(%d,%d)\n", x, y);
287     printf("(%d,%d)", startX,startY);
288     printf("(%d,%d)\n", endX,endY);
289     hh = glutGet(GLUT_WINDOW_HEIGHT);
290     if (button == GLUT_LEFT_BUTTON)
291     {
292         if (state == GLUT_DOWN)
293         {
294             if (!mouseLeftDown) {
295                 startX = x;startY = hh-y;
296             } 
297             
298             mouseLeftDown = true;
299         }
300         else if (state == GLUT_UP) {
301             mouseLeftDown = false;
302    
303         }
304             
305     }
306 
307     else if (button == GLUT_RIGHT_BUTTON)
308     {
309         if (state == GLUT_DOWN)
310         {
311             mouseRightDown = true;
312         }
313         else if (state == GLUT_UP)
314             mouseRightDown = false;
315     }
316 
317 
318     
319 }
320 
321 void mouse_process_active(int x, int y)
322 {
323     if (mouseLeftDown){
324         endX = x;endY = hh - y;
325         glutPostRedisplay();
326     }
327     if(mouseRightDown)
328     {   
329 
330     }
331     glutPostRedisplay();
332 
333 }
334 void mouse_process_passtive(int x, int y) {}
335 
336 
337 int main(int argc, char** argv)
338 {
339     glutInit(&argc, argv);
340     glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
341     glutInitWindowSize(500, 500);
342     glutCreateWindow("19智能 右键开启菜单");
343 
344     init();
345 
346     glutDisplayFunc(display);
347   
348     // later Edition
349     glutMouseFunc(mouse_process);
350     glutMotionFunc(mouse_process_active);
351     glutPassiveMotionFunc(mouse_process_passtive);
352     createGLUTMenus();
353     glutKeyboardFunc(keyboard);
354     glutMainLoop();
355 
356     return 0;
357 }
posted @ 2021-04-01 14:42 Zebro 阅读(659) 评论(0) 编辑收藏举报
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计算机图形学 实验二 DAA与Bresham以及中点圆

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计算机图形学实验二 DAA与Bresham以及中点圆
