/*
 * share-lists.c:
 * Simple display list sharing example.
 *
 * written by Naofumi Yasufuku  <naofumi@users.sourceforge.net>
 */

#include <stdlib.h>

#include <gtk/gtk.h>

#include <gtk/gtkgl.h>

#ifdef G_OS_WIN32
#define WIN32_LEAN_AND_MEAN 1
#include <windows.h>
#endif

#include <GL/gl.h>
#include <GL/glu.h>

static GLfloat red[]    = {1.0, 0.0, 0.0, 1.0};
static GLfloat yellow[] = {1.0, 1.0, 0.0, 1.0};
static GLfloat green[]  = {0.0, 1.0, 0.0, 1.0};

static void
init_gl (GLfloat *light_diffuse)
{
  static GLfloat light_position[] = {1.0, 1.0, 1.0, 0.0};

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

  glClearColor (1.0, 1.0, 1.0, 1.0);
  glClearDepth (1.0);

  glMatrixMode (GL_PROJECTION);
  glLoadIdentity ();
  gluPerspective (40.0, 1.0, 1.0, 10.0);

  glMatrixMode (GL_MODELVIEW);
  glLoadIdentity ();
  gluLookAt (0.0, 0.0, 3.0,
             0.0, 0.0, 0.0,
             0.0, 1.0, 0.0);
  glTranslatef (0.0, 0.0, -3.0);
}

static void
realize_main (GtkWidget *widget,
              GLfloat   *light_diffuse)
{
  GdkGLContext *glcontext = gtk_widget_get_gl_context (widget);
  GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (widget);

  GLUquadricObj *qobj;

  /*** OpenGL BEGIN ***/
  if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
    return;

  /* Create display list #1 */
  qobj = gluNewQuadric ();
  gluQuadricDrawStyle (qobj, GLU_FILL);
  glNewList (1, GL_COMPILE);
  gluSphere (qobj, 1.0, 20, 20);
  glEndList ();

  /* Initialize rendering context */
  init_gl (light_diffuse);

  gdk_gl_drawable_gl_end (gldrawable);
  /*** OpenGL END ***/
}

static void
realize_sub (GtkWidget *widget,
             GLfloat   *light_diffuse)
{
  GdkGLContext *glcontext = gtk_widget_get_gl_context (widget);
  GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (widget);

  /*** OpenGL BEGIN ***/
  if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
    return;

  /* Initialize rendering context */
  init_gl (light_diffuse);

  gdk_gl_drawable_gl_end (gldrawable);
  /*** OpenGL END ***/
}

static gboolean
configure_event (GtkWidget         *widget,
                 GdkEventConfigure *event,
                 gpointer           data)
{
  GdkGLContext *glcontext = gtk_widget_get_gl_context (widget);
  GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (widget);

  /*** OpenGL BEGIN ***/
  if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
    return FALSE;

  glViewport (0, 0,
              widget->allocation.width, widget->allocation.height);

  gdk_gl_drawable_gl_end (gldrawable);
  /*** OpenGL END ***/

  return TRUE;
}

static gboolean
expose_event (GtkWidget      *widget,
              GdkEventExpose *event,
              gpointer        data)
{
  GdkGLContext *glcontext = gtk_widget_get_gl_context (widget);
  GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (widget);

  /*** OpenGL BEGIN ***/
  if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
    return FALSE;

  glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  glCallList (1);

  if (gdk_gl_drawable_is_double_buffered (gldrawable))
    gdk_gl_drawable_swap_buffers (gldrawable);
  else
    glFlush ();

  gdk_gl_drawable_gl_end (gldrawable);
  /*** OpenGL END ***/

  return TRUE;
}

int
main (int   argc,
      char *argv[])
{
  GdkGLConfig *glconfig;
  GdkGLContext *glcontext;

  GtkWidget *window;
  GtkWidget *vbox;
  GtkWidget *drawing_area;
  GtkWidget *button;

  /*
   * Init GTK.
   */

  gtk_init (&argc, &argv);

  /*
   * Init GtkGLExt.
   */

  gtk_gl_init (&argc, &argv);

  /*
   * Configure OpenGL-capable visual.
   */

  /* Try double-buffered visual */
  glconfig = gdk_gl_config_new_by_mode (GDK_GL_MODE_RGB    |
                                        GDK_GL_MODE_DEPTH  |
                                        GDK_GL_MODE_DOUBLE);
  if (glconfig == NULL)
    {
      g_print ("*** Cannot find the double-buffered visual.\n");
      g_print ("*** Trying single-buffered visual.\n");

      /* Try single-buffered visual */
      glconfig = gdk_gl_config_new_by_mode (GDK_GL_MODE_RGB   |
                                            GDK_GL_MODE_DEPTH);
      if (glconfig == NULL)
        {
          g_print ("*** No appropriate OpenGL-capable visual found.\n");
          exit (1);
        }
    }

  /*
   * Top-level window.
   */

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title (GTK_WINDOW (window), "share-lists");

  /* Get automatically redrawn if any of their children changed allocation. */
  gtk_container_set_reallocate_redraws (GTK_CONTAINER (window), TRUE);
  /* Set border width */
  gtk_container_set_border_width (GTK_CONTAINER (window), 10);

  g_signal_connect (G_OBJECT (window), "delete_event",
                    G_CALLBACK (gtk_main_quit), NULL);

  /*
   * VBox.
   */

  vbox = gtk_vbox_new (FALSE, 10);
  gtk_container_add (GTK_CONTAINER (window), vbox);
  gtk_widget_show (vbox);

  /*
   * OpenGL drawing area #1 (main: creates display lists).
   */

  drawing_area = gtk_drawing_area_new ();
  gtk_widget_set_size_request (drawing_area, 120, 120);

  gtk_widget_set_gl_capability (drawing_area,
                                glconfig,
                                NULL,
                                TRUE,
                                GDK_GL_RGBA_TYPE);

  g_signal_connect_after (G_OBJECT (drawing_area), "realize",
                          G_CALLBACK (realize_main), red);
  g_signal_connect (G_OBJECT (drawing_area), "configure_event",
		    G_CALLBACK (configure_event), NULL);
  g_signal_connect (G_OBJECT (drawing_area), "expose_event",
		    G_CALLBACK (expose_event), NULL);

  gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);

  gtk_widget_show (drawing_area);

  /*
   * Get OpenGL rendering context.
   */

  gtk_widget_realize (drawing_area);
  glcontext = gtk_widget_get_gl_context (drawing_area);

  /*
   * OpenGL drawing area #2 (sub: shares display lists).
   */

  drawing_area = gtk_drawing_area_new ();
  gtk_widget_set_size_request (drawing_area, 120, 120);

  gtk_widget_set_gl_capability (drawing_area,
                                glconfig,
                                glcontext, /* share_list */
                                TRUE,
                                GDK_GL_RGBA_TYPE);

  g_signal_connect_after (G_OBJECT (drawing_area), "realize",
                          G_CALLBACK (realize_sub), yellow);
  g_signal_connect (G_OBJECT (drawing_area), "configure_event",
		    G_CALLBACK (configure_event), NULL);
  g_signal_connect (G_OBJECT (drawing_area), "expose_event",
		    G_CALLBACK (expose_event), NULL);

  gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);

  gtk_widget_show (drawing_area);

  /*
   * OpenGL drawing area #3 (sub: shares display lists).
   */

  drawing_area = gtk_drawing_area_new ();
  gtk_widget_set_size_request (drawing_area, 120, 120);

  gtk_widget_set_gl_capability (drawing_area,
                                glconfig,
                                glcontext, /* share_list */
                                TRUE,
                                GDK_GL_RGBA_TYPE);

  g_signal_connect_after (G_OBJECT (drawing_area), "realize",
                          G_CALLBACK (realize_sub), green);
  g_signal_connect (G_OBJECT (drawing_area), "configure_event",
		    G_CALLBACK (configure_event), NULL);
  g_signal_connect (G_OBJECT (drawing_area), "expose_event",
		    G_CALLBACK (expose_event), NULL);

  gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);

  gtk_widget_show (drawing_area);

  /*
   * Simple quit button.
   */

  button = gtk_button_new_with_label ("Quit");

  g_signal_connect (G_OBJECT (button), "clicked",
                    G_CALLBACK (gtk_main_quit), NULL);

  gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);

  gtk_widget_show (button);

  /*
   * Show window.
   */

  gtk_widget_show (window);

  /*
   * Main loop.
   */

  gtk_main ();

  return 0;
}