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OpenGL實現(xiàn)邊緣填充算法

更新時間：2020年02月19日 15:47:06 作者：BYSora

這篇文章主要為大家詳細介紹了OpenGL實現(xiàn)邊緣填充算法，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

邊緣填充的思想：枚舉每一條邊，對這條邊右邊的像素進行求補操作，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[]= {10,70,70,60,40,30,20};
int y[]= {10,10,50,40,60,20,30};
int vis[500][500]; //判斷該坐標的點是否存在
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); //繪制多邊形形狀
 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,0.0f);
   glVertex2i(i,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,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]; //根據(jù)斜率推導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,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("第一個opengl程序");
 init();
 glutDisplayFunc(MidBresenhamCircle);
 glutMainLoop();
 return 0;
}

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