mouse.cpp

#include<GL/glut.h>
#include<stdlib.h>

float r,g,b,x,y;
bool check=true;

void mouse(int button, int state, int mousex, int mousey)
{
    if(button==GLUT_LEFT_BUTTON && state==GLUT_DOWN){
       check=true;       
        x = mousex;
        y = 480-mousey;        
        r=0;g=0;b=0;
        }
            
   else if(button==GLUT_RIGHT_BUTTON && state==GLUT_DOWN){
    glClearColor(1, 1, 1, 0); 
    glClear(GL_COLOR_BUFFER_BIT);
      check = false;        
     }
glutPostRedisplay();
     }
          
void display(void)
{  
    glColor3f(r,g,b); 
    glPointSize(50); 
   
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0.0, 640.0, 0.0, 480.0);

    if(check)  
    {      
           glBegin(GL_POINTS); 
           glVertex2i(x,y);  

      glEnd();
    }
    glFlush();  
}

int main(int argc,char** argv)
{
    glutInit(&argc,argv);
    glutInitWindowSize(640,480);   
    glutInitWindowPosition(10,10);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutCreateWindow("DDA Line Drawing");
        
    glClearColor(1, 1, 1, 0); 
    glClear(GL_COLOR_BUFFER_BIT);
  
    glutDisplayFunc(display);
    glutMouseFunc(mouse);
    glutMainLoop();
}