/* 
 * Original program:
 *
 * gtkglarea-1.2.1/examples/viewlw.c
 * Copyright (C) 1998 Janne Löf <jlof@mail.student.oulu.fi>
 *
 * Conversion to Helium by Edouard.Thiel@lif.univ-mrs.fr
*/


#include <heliumGL.h>
#include "lw.h"


He_node *princ, *panel, *mess, *b_quit, *text, *glarea;
He_trackball info_tb;
lwObject *ze_lwobject = NULL;   /* lightwave object mesh */

int load_lwobject(char *lwobject_name);


void glarea_init (He_node *hn)
{
  GLfloat light0_pos[4]   = { -50.0, 50.0, 0.0, 0.0 };
  GLfloat light0_color[4] = { .6, .6, .6, 1.0 }; /* white light */
  GLfloat light1_pos[4]   = {  50.0, 50.0, 0.0, 0.0 };
  GLfloat light1_color[4] = { .4, .4, 1, 1.0 };  /* cold blue light */

  /* remove back faces */
  glDisable(GL_CULL_FACE);
  glEnable(GL_DEPTH_TEST);
  
  /* speedups */
  glEnable(GL_DITHER);
  glShadeModel(GL_SMOOTH);
  glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST);
  glHint(GL_POLYGON_SMOOTH_HINT, GL_FASTEST);

  /* light */
  glLightfv(GL_LIGHT0, GL_POSITION, light0_pos);
  glLightfv(GL_LIGHT0, GL_DIFFUSE,  light0_color);  
  glLightfv(GL_LIGHT1, GL_POSITION, light1_pos);
  glLightfv(GL_LIGHT1, GL_DIFFUSE,  light1_color);
  glEnable(GL_LIGHT0);
  glEnable(GL_LIGHT1);
  glEnable(GL_LIGHTING);
    
  glColorMaterial(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE);
  glEnable(GL_COLOR_MATERIAL);  
}


void glarea_repaint (He_node *hn)
{
    /* Mode perspective : au lieu de le faire une seule fois dans 
     * l'InitProc, on le fait à chaque fois : ça permet de conserver
     * les proportions de perspective.
    */
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective( HeTbGetFovy(&info_tb), 
                    (GLdouble) HeGetWidth(hn)/HeGetHeight(hn), 
                    1, 100 );

    /* Coordonnées de la scène :
     * on recule tout ce qui va être dessiné ; de la sorte on peut 
     * travailler avec des z autour de 0, et pas uniquement < 0.
    */
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslated (0, 0, -HeTbGetZdist(&info_tb));

    /* On tourne le repère d'après le trackball */
    HeTbMultRotations(&info_tb);
      
    /* Init du fond (bleu opaque) et du Zbuffer */
    glClearColor(.3,.4,.6,1);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    /* On charge l'objet */
    lw_object_show(ze_lwobject);
}

int test_lecture (char *name)
{
    FILE *f = fopen(name, "rb");
    if (f) { fclose(f); return TRUE; }
    return FALSE;
}

void dialog_error (char *message, char *filename)
{
    HeSimpleDialog (
	HE_DIALOG_BELL,
        HE_DIALOG_TITLE,   "WARNING",
        HE_DIALOG_MESSAGE, message,
        HE_DIALOG_QUOTED,  filename,
        HE_DIALOG_BUTTOK,  "OK",
        0);
}

int load_lwobject(char *lwobject_name)
{
    lwObject *lwobject;

    /* read lightwave object */
    if (!test_lecture(lwobject_name)) {
        dialog_error ("Can't open file", lwobject_name);
	return FALSE;
    }
    if (!lw_is_lwobject(lwobject_name)) {
        dialog_error ("This is not a LightWave 3D object", lwobject_name);
	return FALSE;
    }
    lwobject = lw_object_read(lwobject_name);
    if (lwobject == NULL) {
        dialog_error ("Can't read LightWave 3D object", lwobject_name);
	return FALSE;
    }
    lw_object_scale(lwobject, 10.0 / lw_object_radius(lwobject));

    /* set up ze_lwobject and init trackball */
    lw_object_free(ze_lwobject);
    ze_lwobject = lwobject;
    HeTbInitRotations(&info_tb);
    HeTbInitFovy(&info_tb, 45, 5, 120);
    HeTbInitZdist(&info_tb, 30, 10, 50);

    return TRUE;
}


void glarea_event (He_node *hn, He_event *hev)
{
    switch (hev->type) {
    
	case ButtonPress : 
	    HeTbMemoPointer (&info_tb, hev);
            break;
        
	case MotionNotify :
            switch (hev->sb) {
                case 1 : HeTbEventRotations(&info_tb, hn, hev);
                	 HePostRepaint(hn);
                         break;
                case 2 : HeTbEventFovy (&info_tb, hn, hev);
                	 HePostRepaint(hn);
                         break;
                case 3 : HeTbEventZdist (&info_tb, hn, hev);
                	 HePostRepaint(hn);
                         break;
            }
            break;
    }
}


void text_notify_proc (He_node *hn)
{
    char *name = HeGetTextValue (hn);
    
    /* charge le fichier */
    if (load_lwobject (name));
	HePostRepaint (glarea);
}


void princ_resize (He_node *hn, int width, int height)
{
    int wmin = HeGetWidth(mess) + HeGetWidth (b_quit) + 100;
    if (width < wmin) { 
	HeSetWidth (hn, wmin);
    } else {
        HeSetWidth (panel, width);
        HeJustify (b_quit, NULL, HE_RIGHT);
        HeExpand (text, b_quit, HE_RIGHT);
        HeExpand (glarea, NULL, HE_BOTTOM_RIGHT);
    }
    HeFlushDisplay();
}

void butt_proc (He_node *hn)
{
    char *name = HeGetButtonLabel (hn);
    
    if (strcmp (name, "Quit") == 0) HeQuit(0);
}

int main (int argc, char *argv[])
{
    int attr_list[] = {
      GLX_RGBA,
      GLX_DOUBLEBUFFER,
      GLX_DEPTH_SIZE, 1,
      None
    };
  
    HeInit (&argc, &argv);
    
    if (argc != 2) {
        printf ("USAGE: %s [options] file.lwo\n", he_base_name);
        printf ("Type \"%s -help\" to get options\n", he_base_name);
        HeQuit (1);
    }

    princ = HeCreateFrame();
    HeSetFrameLabel (princ, "View LightWave 3D objects");
    HeSetFrameResizeProc (princ, princ_resize);
    
    panel = HeCreatePanel (princ);
    
    mess = HeCreateMessageP (panel, "File:", TRUE);
    text = HeCreateText (panel);
    HeSetTextNotifyProc (text, text_notify_proc);
    HeSetTextCompletion (text, TRUE);
    HeSetWidth (text, 20);
    HeSetTextValue (text, argv[1]);

    b_quit = HeCreateButtonP (panel, "Quit", butt_proc, NULL);
        
    HeFit (panel);
    
    glarea = HeCreateGLArea (princ, attr_list, NULL);
    HeSetY (glarea, HeGetHeight(panel)+2);
    HeSetWidth (glarea, 300);
    HeSetHeight (glarea, 300);
    HeSetGLAreaInitProc (glarea, glarea_init);
    HeSetGLAreaRepaintProc (glarea, glarea_repaint);
    HeSetGLAreaEventProc (glarea, glarea_event);
    
    load_lwobject(HeGetTextValue(text));
    
    HeSetTip (glarea,
	"Bouton 1 : rotations\n"
	"Bouton 2 : angle de vue\n"
	"Bouton 3 : distance" );
   
    HeFit (princ);
    
    return HeMainLoop (princ);
}