/*  Two Windows Example

This program uses materials from Mark J. Kilgard in order to display
two different windows.  It uses a function to tell which window is
active, and also shows the use of mouse functions in different windows.
The program creates two objects that are defined by a display list
and called when needed.  This approach is more efficient for certain
problems. 

*/

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

GLfloat light_diffuse[] = {2.0, 2.0, 1.0, 1.0};
GLfloat light_position[] = {5.0, 5.0, 5.0, 0.0};
GLUquadricObj *qobj;

// Window variables
int win1, win2; 

// Display List
int list = 1;

void display(void) // Display routine for both Window 1 and 2
{
  glClearColor(0.4, 0.4, 0.6, 1.0);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  if (glutGetWindow() == win1) 
    { // Displaying Window 1
      glColor3f(1.0, 0.0, 0.0);
      glPushMatrix();
        glRotatef(60.0, 0.0, 1.0, 0.0);
        glutWireCube(3.0);
      glPopMatrix();
      glCallList(list);   /* render sphere display list for object 1 */
    }
   else 
    { // Displaying Window 2
      glCallList(1);      /* render sphere display list for object 1 */
      glPushMatrix();
        glTranslatef(0.6, 0.6, 0.8); 
        glCallList(2);    /* render sphere display list for object 2 */
      glPopMatrix();
    }
  glutSwapBuffers();
}

void display_win1(void)  // Initial Window 1 display calls the other routine
{
  glPushMatrix();
  glTranslatef(0.0, 0.0, -3.0);
  display();
  glPopMatrix();
}
 
// This function can tell which window is being left or entered
void which_window(int state)
{
  printf("%s  Window %d \n",
    state == GLUT_LEFT ? "Leaving" : "Entering",
    glutGetWindow());
}


// Simple Mouse Function
void mouse(int button, int state, int x, int y)
{
  printf("button: %d %s %d,%d\n", button, state == GLUT_UP ? "UP" : "down", x, y);
}

void init(void)
{
  // Define first Quadric Object, a solid sphere as a call list.
  gluQuadricDrawStyle(qobj, GLU_FILL);
  glNewList(1, GL_COMPILE);  /* create sphere display list for Object 1*/
    gluSphere(qobj,  1.0,  20,  20);
  glEndList();

  // Create a second Quadric Object, a wireframe sphere
  gluQuadricDrawStyle(qobj, GLU_LINE);
  glNewList(2, GL_COMPILE);  /* create sphere display list for Object 2*/
    gluSphere(qobj,  0.5,  10,  10);
  glEndList();

  glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
  glLightfv(GL_LIGHT0, GL_POSITION, light_position);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_DEPTH_TEST);

  glMatrixMode(GL_PROJECTION);
  gluPerspective( 40.0, 1.0, 1.0,  20.0);
  glMatrixMode(GL_MODELVIEW);
  gluLookAt(0.0, 0.0, 5.0,  0.0, 0.0, 0.0,  0.0, 1.0, 0.); 
  glTranslatef(0.0, 0.0, -1.0);
}

int main(int argc, char **argv)
{
  qobj = gluNewQuadric();
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);

// Create First Window
  win1 = glutCreateWindow("First Window");
  glutEntryFunc(which_window);
  glutMouseFunc(mouse);
  init();
  glutDisplayFunc(display_win1);

// Create Second Window
  win2 = glutCreateWindow("Second Window");
  glutEntryFunc(which_window);
  glutMouseFunc(mouse);
  init();
  glutDisplayFunc(display);

  glutMainLoop();
  return 0;             /* ANSI C requires main to return int. */
}