mouse.cpp

#include<gl/glut.h>
GLint topLeftX, topLeftY, bottomRightX, bottomRightY;
void MyDisplay()
{
 glViewport(0,0,300,300);
 glClear(GL_COLOR_BUFFER_BIT);
 glColor3f(0.5,0.5,0.5);

 glBegin(GL_POLYGON);
 glVertex3f(topLeftX/300.0,(300-topLeftY)/300.0,0.0);
 
 glVertex3f(topLeftX/300.0,(300-bottomRightY)/300.0,0.0);
 
 glVertex3f(bottomRightX/300.0,(300-bottomRightY)/300.0,0.0);
 
 glVertex3f(bottomRightX/300.0,(300-topLeftY)/300.0,0.0);
 glEnd();
 glFlush();
}
void MyMouseClick(GLint button, GLint state, GLint x, GLint y)
{
 if(button==GLUT_LEFT_BUTTON && state ==GLUT_DOWN)
 {
  topLeftX=x;
  topLeftY=y;
 }
}
void MyMouseMove(GLint x, GLint y)
{
 bottomRightX=x;
 bottomRightY=y;

 glutPostRedisplay();
}
int main(int argc,char** argv)
{
 glutInit(&argc,argv);
 glutInitDisplayMode(GLUT_RGB);
 glutInitWindowSize(300,300);
 glutInitWindowPosition(0,0);
 glutCreateWindow("Mouse Test");
 glMatrixMode(GL_PROJECTION);
 glLoadIdentity();
 glClearColor(1.0,1.0,1.0,1.0);
 glOrtho(0.0,1.0,0.0,1.0,-1.0,1.0);

 glutDisplayFunc(MyDisplay);
 glutMouseFunc(MyMouseClick);
 glutMotionFunc(MyMouseMove);
 glutMainLoop();
}