13. Graphics Program for Boundary-Fill Algorithm.

#include <iostream>
#include <GL/glut.h>
#include <GL/gl.h>
void init();
void display();
void setPixel(int,int);
void getPixel(int,int,float*);
void mouse(int,int,int,int);
float borderColor[3]={0,0,1}, fillColor[3]={0,0,1};
int main(int argc,char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
glutInitWindowSize(400,400);
glutInitWindowPosition(400,400);
glutCreateWindow("Project");
init();
glutDisplayFunc(display);
glutMouseFunc(mouse);
glutMainLoop();
return 0;
}
bool match(float* x1,float* x2)
{
return (x1[0] == x2[0] && x1[1] == x2 [1] && x1[2] == x2[2]);
}
void boundaryFill4(int x,int y)
{
float interiorColor[3];
getPixel(x,y,interiorColor);
if(!match(interiorColor,borderColor)&&!match(interiorColor,fillColor))
{
setPixel(x,y);
boundaryFill4(x+1,y);
boundaryFill4(x-1,y);
boundaryFill4(x,y+1);
boundaryFill4(x,y-1);
} }

void mouse(int button,int state,int x,int y)
{
boundaryFill4(x,y);
glFlush();
}
void draw()
{
glBegin(GL_LINE_LOOP);
glVertex2i(100,100);
glVertex2i(300,100);
glVertex2i(300,300);
glVertex2i(100,300);
glEnd();
}
void setPixel(int x,int y)
{
glBegin(GL_POINTS);
glColor3fv(borderColor);
glVertex2i(x,y);
glEnd();
}
void getPixel(int x,int y,float* color)
{
glReadPixels(x,y,1,1,GL_RGB,GL_FLOAT,color);
}
void display()
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3fv(borderColor);
draw();
glFlush();
}
void init()
{
glClearColor(0.0,0.0,0.0,0.0);
glMatrixMode(GL_PROJECTION);
gluOrtho2D(0.0,400.0,400.0,0.0);
}