clicking a square mesh and printing the value of the square

Dear All,
I have one more doubt,

When I click the mouse on a square(say 3rd square on the 5th row), in the mesh it should print
the print as row = 5 and colum = 3)

I used glutMouseFunc(mouse) and wrote the following code for mouse call back. But it is not printing the exact row column value.

 

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

void make_mesh()
{
   float x, y;
   glBegin(GL_LINES);
   for (x = -5; x <= 5; x += 1.0f)						// x += 1.0f Stands For 1 Meter Of Space In This Example
   {
		glVertex3f(x, 5.0, 0);
		glVertex3f(x, -5.0, 0);
   }
  // Draw The Horizontal Lines
   for (y = -5; y <= 5; y += 1.0f)						// y += 1.0f Stands For 1 Meter Of Space In This Example
   {
		glVertex3f( 5.0, y, 0);
		glVertex3f( -5.0, y, 0);
   }
   glEnd();
}

void init(void) 
{
   glClearColor (0.0, 0.0, 0.0, 0.0);
   glShadeModel (GL_FLAT);
}

void display(void)
{
   glClear (GL_COLOR_BUFFER_BIT);
   glColor3f (1.0, 1.0, 1.0);
   glLoadIdentity();
		make_mesh();
   glFlush();
}


void reshape (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h); 
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
   glOrtho(-5.0, 5.0, -5.0, 5.0, -1.0, 1.0);
   glMatrixMode (GL_MODELVIEW);
}

void mouse(int button, int state, int x, int y)
{
	int mx = x * 10/500;
	int my = y * 10/500;
	printf("Value of x = %d
", x);
	printf("Value of y = %d
", y);

}
void keyboard(unsigned char key, int x, int y)
{
   switch (key) {
      case 27:
         exit(0);
         break;
   }
}

int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
   glutInitWindowSize (500, 500); 
   glutInitWindowPosition (100, 100);
   glutCreateWindow (argv[0]);
   init();
   glutDisplayFunc(display); 
   glutReshapeFunc(reshape);
   glutKeyboardFunc(keyboard);
   glutMouseFunc(mouse);
   glutMainLoop();
   return 0;
}


 

I think the problem is that you’re using integer values for your calculations.

in

if x10/500 is evaluated as x(10/500) then 10/500 in integer calculus is 0.

Try this:

void mouse(int button, int state, int x, int y)

{

int mx = int(x*10.0/500.0);

int my = int(y*10.0/500.0);

printf("Value of x = %d
", x);

printf("Value of y = %d
", y);


}

P.S. I believe in glut y=0 is the top of the screen and not the bottom like in OpenGL.

Nico

Yeah I changed, But it is still not working

hey iris_raj, try this:

void mouse(int button, int state, int x, int y)
{	
    int mx = (x * 10)/screenWidth;	
    int my = (y * 10)/screenHeight;	

    // you had a typo here, mx not x, my not y!
    printf("Value of x = %d
", mx);	
    printf("Value of y = %d
", my);
}