/****************************************************************************

 Copyright (C) 2002-2006 Gilles Debunne (Gilles.Debunne@imag.fr)

This file is part of the QGLViewer library.
 Version 2.2.4-1, released on December 12, 2006.

 http://artis.imag.fr/Members/Gilles.Debunne/QGLViewer

 libQGLViewer is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 libQGLViewer is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with libQGLViewer; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*****************************************************************************/

// TP OpenGL: Joerg Liebelt, Serigne Sow
#include "sky.h"


bool SKY::LoadTexture( int side, char* filename )
{
  QImage image;
  if (image.load(filename))
    {
      textures[side] = QGLWidget::convertToGLFormat(image);

      //construire les textures openGL
      glGenTextures( 1, &(texIDs[side]) );
      glBindTexture( GL_TEXTURE_2D, (texIDs[side]) );
      glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
      glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );

      //les deux commandes suivantes servent a elargir la texture pq. la surface soit remplie;
      //.. clamp_to_edge = repeter la derniere ligne de la texture (marche bien ici)
      glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
      glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
      glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, textures[side].width(), textures[side].height(), 0,
		    GL_RGBA, GL_UNSIGNED_BYTE, textures[side].bits() );
    }
  else
    {
      qWarning("Sky texture loading failed for side %d",side);
      return false;
    }
  return true;
}


void SKY::Render()
{
  //on ne veut pas que le background disparaisse (POURTANT, IL DISPARAIT!! J'y arrive pas...)
  //glDisable( GL_CULL_FACE );
  //glDisable( GL_DEPTH_TEST );
  //glDepthMask( GL_FALSE );
  glDisable(GL_LIGHTING);

  glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
  glEnable( GL_TEXTURE_2D );
  glPushMatrix( );
  //on construit a partir de la position de la camera (ou du milieu...)
  glTranslatef( vecCenter[0], vecCenter[1], vecCenter[2] );

  //face
  glBindTexture( GL_TEXTURE_2D, texIDs[SKY_FRONT] );
  glBegin( GL_TRIANGLE_FAN );
  glTexCoord2f( 1.0f, 1.0f ); glVertex3f( vecMax[0], vecMax[1], vecMax[2] );
  glTexCoord2f( 1.0f, 0.0f ); glVertex3f( vecMax[0], vecMin[1], vecMax[2] );
  glTexCoord2f( 0.0f, 0.0f ); glVertex3f( vecMin[0], vecMin[1], vecMax[2] );
  glTexCoord2f( 0.0f, 1.0f ); glVertex3f( vecMin[0], vecMax[1], vecMax[2] );
  glEnd( );

  //derriere
  glBindTexture( GL_TEXTURE_2D, texIDs[SKY_BACK]);
  glBegin( GL_TRIANGLE_FAN );
  glTexCoord2f( 1.0f, 1.0f ); glVertex3f( vecMin[0], vecMax[1], vecMin[2] );
  glTexCoord2f( 1.0f, 0.0f ); glVertex3f( vecMin[0], vecMin[1], vecMin[2] );
  glTexCoord2f( 0.0f, 0.0f ); glVertex3f( vecMax[0], vecMin[1], vecMin[2] );
  glTexCoord2f( 0.0f, 1.0f ); glVertex3f( vecMax[0], vecMax[1], vecMin[2] );
  glEnd( );

  //droite
  glBindTexture( GL_TEXTURE_2D, texIDs[SKY_RIGHT] );
  glBegin( GL_TRIANGLE_FAN );
  glTexCoord2f( 1.0f, 1.0f ); glVertex3f( vecMax[0], vecMax[1], vecMin[2] );
  glTexCoord2f( 1.0f, 0.0f ); glVertex3f( vecMax[0], vecMin[1], vecMin[2] );
  glTexCoord2f( 0.0f, 0.0f ); glVertex3f( vecMax[0], vecMin[1], vecMax[2] );
  glTexCoord2f( 0.0f, 1.0f ); glVertex3f( vecMax[0], vecMax[1], vecMax[2] );
  glEnd( );

  //gauche
  glBindTexture( GL_TEXTURE_2D, texIDs[SKY_LEFT] );
  glBegin( GL_TRIANGLE_FAN );
  glTexCoord2f( 1.0f, 1.0f ); glVertex3f( vecMin[0], vecMax[1], vecMax[2] );
  glTexCoord2f( 1.0f, 0.0f ); glVertex3f( vecMin[0], vecMin[1], vecMax[2] );
  glTexCoord2f( 0.0f, 0.0f ); glVertex3f( vecMin[0], vecMin[1], vecMin[2] );
  glTexCoord2f( 0.0f, 1.0f ); glVertex3f( vecMin[0], vecMax[1], vecMin[2] );
  glEnd( );

  //au-dessus
  glBindTexture( GL_TEXTURE_2D, texIDs[SKY_TOP] );
  glBegin( GL_TRIANGLE_FAN );
  glTexCoord2f( 0.0f, 0.0f ); glVertex3f( vecMin[0], vecMax[1], vecMax[2] );
  glTexCoord2f( 0.0f, 1.0f ); glVertex3f( vecMin[0], vecMax[1], vecMin[2] );
  glTexCoord2f( 1.0f, 1.0f ); glVertex3f( vecMax[0], vecMax[1], vecMin[2] );
  glTexCoord2f( 1.0f, 0.0f ); glVertex3f( vecMax[0], vecMax[1], vecMax[2] );
  glEnd( );

  //au-dessous
  glBindTexture( GL_TEXTURE_2D, texIDs[SKY_BOTTOM] );
  glBegin( GL_TRIANGLE_FAN );
  glTexCoord2f( 0.0f, 0.0f ); glVertex3f( vecMin[0], vecMin[1], vecMin[2] );
  glTexCoord2f( 0.0f, 1.0f ); glVertex3f( vecMin[0], vecMin[1], vecMax[2] );
  glTexCoord2f( 1.0f, 1.0f ); glVertex3f( vecMax[0], vecMin[1], vecMax[2] );
  glTexCoord2f( 1.0f, 0.0f ); glVertex3f( vecMax[0], vecMin[1], vecMin[2] );
  glEnd( );
  glPopMatrix( );
  //glDepthMask( GL_TRUE );
  //glEnable( GL_DEPTH_TEST );
  //glEnable( GL_CULL_FACE );
}