opengl中点画圆算法（opengl中点画线算法）

本文实例为大家分享了OpenGL绘制直线和圆的具体代码，供大家参考，具体内容如下

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 #include <gl/glut.h> #include <math.h> static int i=1; void Initial(void) { glClearColor(1.0f, 1.0f, 1.0f, 1.0f); //设置窗口背景颜色为白色 glMatrixMode(GL_PROJECTION); //指定设置投影参数 gluOrtho2D(-200.0,200.0,-200.0,200.0); //设置投影参数 //指的是视图范围，如果(0,200,0,200)的话就只能在第一象限显示，就1/4圆，第1，3的参数是左下角坐标，第2，4的参数是右上角坐标 } /*void Display(void) { glClear(GL_COLOR_BUFFER_BIT); //用当前背景色填充窗口 glColor3f(1.0f, 0.0f, 0.0f); //设置当前的绘图颜色为红色 glRectf(50.0f, 100.0f, 150.0f, 50.0f); //绘制一个矩形 glFlush(); //处理所有的OpenGL程序 } */ void DDALine(int x0,int y0,int x1,int y1) { //glVertex2f(10,10); int dx,dy,epsl,k; float x,y,xIncre,yIncre; dx = x1 - x0; dy = y1 - y0; x = x0; y = y0; if(abs(dx)>abs(dy)) epsl=abs(dx); else epsl=abs(dy); xIncre=(float)dx/(float)epsl; yIncre=(float)dy/(float)epsl; glPointSize(2); glBegin(GL_POINTS); for(k = 0;k <= epsl; k++) { glColor3f(1.0f, 0.0f, 0.0f); glVertex2f(int(x+0.5),int(y+0.5)); x += xIncre; y += yIncre; } glEnd(); } void Mid_B(int x0,int y0,int x1,int y1) { int dx,dy,d,UpIncre,DownIncre,x,y; if(x0 > x1) { x = x1; x1 = x0; x0 = x; y = y1; y1 = y0; y0 = y; } x = x0; y = y0; dx = x1 - x0; dy = y1 - y0; d = dx - 2*dy; UpIncre = 2*dx - 2*dy; DownIncre =- 2*dy; glPointSize(2); glBegin(GL_POINTS); while(x <= x1) { glColor3f(1.0f, 0.0f, 0.0f); glVertex2f(x,y); x++; if(d < 0) { y++; d += UpIncre; } else d += DownIncre; } glEnd(); } void G_B(int x0,int y0,int x1,int y1) { int x,y,dx,dy,e; dx = x1 - x0; dy = y1 - y0; e =- dx; x=x0; y=y0; glPointSize(2); glBegin(GL_POINTS); while(x <= x1) { glColor3f(1.0f, 0.0f, 0.0f); glVertex2f(x,y); x++; e = e + 2*dy; if(e > 0) { y++; e = e - 2*dx; } } glEnd(); } void CirclePoint(int x, int y) { glPointSize(2); glBegin(GL_POINTS); glColor3f(1.0f, 0.0f, 0.0f); glVertex2f(x,y); glVertex2f(y,x); glVertex2f(-y,x); glVertex2f(-x,y); glVertex2f(-x,-y); glVertex2f(-y,-x); glVertex2f(y,-x); glVertex2f(x,-y); glEnd(); } void MidBresenhamCircle(int r) { int x = 0, y = r, d = 1-r; //glPointSize(2); //glBegin(GL_POINTS); while(x <= y) { CirclePoint(x,y); if(d < 0) d += 2*x+3; else { d += 2*(x-y)+5; y--; } x++; } glEnd(); } void ProcessMenu(int value) { i = value; glutPostRedisplay(); } void Display(void) { glClear(GL_COLOR_BUFFER_BIT); //用当前背景色填充窗口 glViewport(0,0,400,400); //前两个参数改变原点坐标，后两个参数改变图形长宽（放大缩小） switch(i) { case 1: DDALine(2,3,55,83); break; case 2: Mid_B(2,3,55,83); break; case 3: G_B(2,3,55,83); break; case 4: MidBresenhamCircle(50); break; } glFlush(); } int main(int argc, char* argv[]) { glutInit(&argc, argv); //初始化GLUT库,处理命令行参数 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); //初始化窗口的显示模式 glutInitWindowSize(400,400); //设置窗口的尺寸 glutInitWindowPosition(100,100); //设置窗口的位置 glutCreateWindow("直线"); //创建一个名为矩形的窗口 int MainMenu = glutCreateMenu(ProcessMenu); //创建主菜单 glutAddMenuEntry("DDA算法",1); glutAddMenuEntry("中点Bresenham算法",2); glutAddMenuEntry("改进的Bresenham算法",3); glutAddMenuEntry("中点bresenham画圆",4); glutAttachMenu(GLUT_RIGHT_BUTTON); glutDisplayFunc(Display); //设置当前窗口的显示回调函数 Initial(); //完成窗口初始化 glutMainLoop(); //启动主GLUT事件处理循环 return 0; }