7 Program to fill Polygon using Boundary Fill Algorithm in OpenGL ~ Coding Atharva

Program:
#include<GL/glut.h>
#include<iostream>

using namespace std;

void myInit()
{
    gluOrtho2D(0,500,0,500); 
    glClearColor(1,1,1,1);
    glMatrixMode(GL_PROJECTION);
    glColor3f(1,0,0);
}

void plotPixel(int x,int y,float* fill_color)
{
    glColor3f(fill_color[0],fill_color[1],fill_color[2]);
    
    glBegin(GL_POINTS);
        glVertex2i(x,y);
    glEnd();

    glFlush();    
}


void boundaryFill(int x,int y,float* fill_color,float* boundary_color)
{
    float current[3];
    
    glReadPixels(x,y,1.0,1.0,GL_RGB,GL_FLOAT,current);
   
    if((current[0] != boundary_color[0] || current[1] != boundary_color[1] ||current[2] != boundary_color[2] ) &&
    (current[0] != fill_color[0] || current[1] != fill_color[1] ||current[2] != fill_color[2] ))
    {
        plotPixel(x,y,fill_color);
        boundaryFill(x+1,y,fill_color,boundary_color);
        boundaryFill(x,y+1,fill_color,boundary_color);
        boundaryFill(x-1,y,fill_color,boundary_color);
        boundaryFill(x,y-1,fill_color,boundary_color);
    }
}

void polygonShape()
{
    glClear(GL_COLOR_BUFFER_BIT);

    glBegin(GL_LINE_LOOP);
        glVertex2i(100,100);
        glVertex2i(250,100);
        glVertex2i(250,300);
        glVertex2i(400,300);
        glVertex2i(400,450);
        glVertex2i(240,450);
        glVertex2i(240,310);
        glVertex2i(100,310);
    glEnd();

    glFlush();

    float boundary_color[3],fill_color[3];
    
    boundary_color[0] = 1;
    boundary_color[1] = 0;
    boundary_color[2] = 0;
    
    
    fill_color[0]=0;
    fill_color[1]=1;
    fill_color[2]=0;

    boundaryFill(102,102,fill_color,boundary_color);
}

int main(int argc,char **argv)
{
   glutInit(&argc, argv);       // Initializing the library
   glutInitWindowSize(500,500);
   glutInitWindowPosition(400,150);
   glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB); 
   glutCreateWindow("Boudary Fill");
 
   myInit(); 
   glutDisplayFunc(polygonShape);

   glutMainLoop(); 
   return 0;
}
Output:
7 Program to fill Polygon using Boundary Fill Algorithm in OpenGL

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