Thursday, May 15, 2014

Opengl,C++ : Flood-Fill Algorithm Using Recursion

  #include <GL/glut.h>   
  int ww = 600, wh = 500;   
  float bgCol[3] = {0.2, 0.4,0.0};   
  float intCol[3] = {1.0,0.0,0.0};   
  float fillCol[3] = {0.4,0.0,0.0};   
      void setPixel(int pointx, int pointy, float f[3])   
      {   
             glBegin(GL_POINTS);   
                  glColor3fv(f);   
                  glVertex2i(pointx,pointy);   
             glEnd();   
             glFlush();   
      }   
      void getPixel(int x, int y, float pixels[3])   
      {   
           glReadPixels(x,y,1.0,1.0,GL_RGB,GL_FLOAT,pixels);   
      }   
      void drawPolygon(int x1, int y1, int x2, int y2)   
       {      
             glColor3f(1.0, 0.0, 0.0);   
             glBegin(GL_POLYGON);   
                     glVertex2i(x1, y1);    
                  glVertex2i(x1, y2);   
                  glVertex2i(x2, y2);   
                     glVertex2i(x2, y1);   
             glEnd();   
             glFlush();   
       }   
       void display()   
       {   
             glClearColor(0.2, 0.4,0.0, 1.0);   
             glClear(GL_COLOR_BUFFER_BIT);   
             drawPolygon(150,250,200,300);   
             glFlush();   
       }   
       void floodfill4(int x,int y,float oldcolor[3],float newcolor[3])   
       {   
            float color[3];   
            getPixel(x,y,color);   
            if(color[0]==oldcolor[0] && (color[1])==oldcolor[1] && (color[2])==oldcolor[2])   
            {   
                     setPixel(x,y,newcolor);   
                     floodfill4(x+1,y,oldcolor,newcolor);   
                     floodfill4(x-1,y,oldcolor,newcolor);   
                  floodfill4(x,y+1,oldcolor,newcolor);   
                  floodfill4(x,y-1,oldcolor,newcolor);   
             }   
       }   
       void mouse(int btn, int state, int x, int y)   
       {   
             if(btn==GLUT_LEFT_BUTTON && state == GLUT_DOWN)    
            {   
                     int xi = x;   
                     int yi = (wh-y);   
                     floodfill4(xi,yi,intCol,fillCol);   
             }   
       }   
       void myinit()   
       {      
            glViewport(0,0,ww,wh);   
            glMatrixMode(GL_PROJECTION);   
            glLoadIdentity();   
            gluOrtho2D(0.0,(GLdouble)ww,0.0,(GLdouble)wh);   
            glMatrixMode(GL_MODELVIEW);   
       }   
       int main(int argc, char** argv)   
       {   
             glutInit(&argc,argv);   
             glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);   
             glutInitWindowSize(ww,wh);   
             glutCreateWindow("Flood-Fill-Recursive");   
             glutDisplayFunc(display);   
             myinit();   
             glutMouseFunc(mouse);   
             glutMainLoop();   
             return 0;   
       }   

2 comments:

  1. Replies
    1. If the size of the polygon is small, it will work. but the size is large it won't work because stack size is not enough to hold. while recursion stack data structure will be used.

      Delete