OpenGL實現邊緣填充演算法
阿新 • • 發佈:2020-02-20
邊緣填充的思想:列舉每一條邊,對這條邊右邊的畫素進行求補操作,就是有填充則去掉,無填充就進行填充
#include <GL/gl.h> #include <GL/glut.h> #include <iostream> #include <cmath> #include <cstring> #include <string> using namespace std; int x[]= {10,70,60,40,30,20}; int y[]= {10,10,50,20,30}; int vis[500][500]; //判斷該座標的點是否存在 void init() { glClearColor (0.0,0.0,0.0); glMatrixMode (GL_PROJECTION); gluOrtho2D (0.0,200.0,150.0); } void MidBresenhamCircle() { memset(vis,sizeof(vis)); glClear(GL_COLOR_BUFFER_BIT); glLineWidth(2); glBegin(GL_LINES); //繪製多邊形形狀 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) //特殊處理k=0的邊 { if(!vis[i][j]) { glColor3f(0.0f,1.0f,0.0f); glVertex2i(i,j); vis[i][j]=1; } else { glColor3f(0.0f,0.0f,j); vis[i][j]=1; } } for(int j=y[1]; j<=y[2]; ++j) //特殊處理k不存在的邊 { for(int i=x[1]; i<300; ++i) { if(!vis[i][j]) { glColor3f(0.0f,0.0f); glVertex2i(i,j); vis[i][j]=1; } else { glColor3f(0.0f,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]; //根據斜率推匯出這條直線的各個點 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,0.0f); glVertex2i(px,j); vis[px][j]=1; } else { glColor3f(0.0f,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("第一個opengl程式"); init(); glutDisplayFunc(MidBresenhamCircle); glutMainLoop(); return 0; }
效果
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