BoundaryFill.c

#include <stdio.h>
#include <math.h>
#include <time.h>
#include <GL/glut.h>
#include <GL/gl.h>
float a2,b2,c2;
void init(){
    glClearColor(1.0,1.0,1.0,0.0);
    glMatrixMode(GL_PROJECTION);
    gluOrtho2D(0,640,0,480);
}

void boundary(int x, int y, float* fillColor, float* bcol){
    float color[3];
    glReadPixels(x,y,1.0,1.0,GL_RGB,GL_FLOAT,color);
    if((color[0]!=bcol[0] || color[1]!=bcol[1] || color[2]!=bcol[2])&&(
     color[0]!=fillColor[0] || color[1]!=fillColor[1] || color[2]!=fillColor[2])){
        glColor3f(fillColor[0],fillColor[1],fillColor[2]);
        glBegin(GL_POINTS);
            glVertex2i(x,y);
        glEnd();
        glFlush();
        boundary(x+1,y,fillColor,bcol);
        boundary(x-1,y,fillColor,bcol);
        boundary(x,y+1,fillColor,bcol);
        boundary(x,y-1,fillColor,bcol);
    }
}

void mouse(int btn, int state, int x, int y){
    y = 480-y;
    if(btn==GLUT_LEFT_BUTTON)
    {
        if(state==GLUT_DOWN)
        {   float bCol[] = {0,0,0};
            float color[] = {a2,b2,c2};
            boundary(x,y,color,bCol);
        }
    }
}

void world(){
    glLineWidth(3);
    glPointSize(2);
    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(0,0,0);
    glBegin(GL_LINE_LOOP);
        glVertex2i(150,100);
        glVertex2i(150,300);
        glVertex2i(450,300);
        glVertex2i(450,100);
    glEnd();
    glFlush();
}

int main(int argc, char** argv){
    printf("Enter RGB values for filling colour= ");
    scanf("%f%f%f",&a2,&b2,&c2);
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
    glutInitWindowSize(640,480);
    glutInitWindowPosition(200,200);
    glutCreateWindow("7.1 Boundary Fill");
    glutDisplayFunc(world);
    glutMouseFunc(mouse);
    init();
    glutMainLoop();
    return 0;
}