opengl绘制填充圆（opengl描边）

边缘填充的思想：枚举每一条边，对这条边右边的像素进行求补操作，就是有填充则去掉，无填充就进行填充

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 #include <GL/gl.h> #include <GL/glut.h> #include <iostream> #include <cmath> #include <cstring> #include <string> using namespace std; int x[]= {10,70,70,60,40,30,20}; int y[]= {10,10,50,40,60,20,30}; int vis[500][500]; //判断该坐标的点是否存在 void init() { glClearColor (0.0, 0.0, 0.0, 0.0); glMatrixMode (GL_PROJECTION); gluOrtho2D (0.0, 200.0, 0.0, 150.0); } void MidBresenhamCircle() { memset(vis,0,sizeof(vis)); glClear(GL_COLOR_BUFFER_BIT); glLineWidth(2); glBegin(GL_LINES); //绘制多边形形状 for(int i=0; i<7; ++i) { glVertex2i(x[i],y[i]); glVertex2i(x[(i+1)%7],y[(i+1)%7]); } glEnd(); glFlush(); glPointSize(2); glBegin(GL_POINTS); for(int i=x[1],j=y[1]; i<300; ++i) //特殊处理k=0的边 { if(!vis[i][j]) { glColor3f(0.0f,1.0f,0.0f); glVertex2i(i,j); vis[i][j]=1; } else { glColor3f(0.0f,0.0f,0.0f); glVertex2i(i,j); vis[i][j]=1; } } for(int j=y[1]; j<=y[2]; ++j) //特殊处理k不存在的边 { for(int i=x[1]; i<300; ++i) { if(!vis[i][j]) { glColor3f(0.0f,1.0f,0.0f); glVertex2i(i,j); vis[i][j]=1; } else { glColor3f(0.0f,0.0f,0.0f); glVertex2i(i,j); vis[i][j]=1; } } } for(int p=2; p<7; ++p) { int k=(y[(p+1)%7]-y[p])/(x[(p+1)%7]-x[p]); //求出斜率 int x1=x[(p+1)%7],x0=x[p],y1=y[(p+1)%7],y0=y[p]; //根据斜率推导出这条直线的各个点 if(y1<y0) { swap(x1,x0); swap(y1,y0); } for(int j=y0; j<=y1; ++j) { int i=(j-y0+k*x0)/k; for(int px=i; px<300; ++px) { if(!vis[px][j]) { glColor3f(0.0f,1.0f,0.0f); glVertex2i(px,j); vis[px][j]=1; } else { glColor3f(0.0f,0.0f,0.0f); glVertex2i(px,j); vis[px][j]=0; } } } } glEnd(); glFlush(); } int main(int argc, char *argv[]) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE); glutInitWindowPosition(100, 100); glutInitWindowSize(500, 500); glutCreateWindow("第一个opengl程序"); init(); glutDisplayFunc(MidBresenhamCircle); glutMainLoop(); return 0; }