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

 Copyright (C) 2002-2008 Gilles Debunne. All rights reserved.

 This file is part of the QGLViewer library version 2.3.9.

 http://www.libqglviewer.com - contact@libqglviewer.com

 This file may be used under the terms of the GNU General Public License 
 versions 2.0 or 3.0 as published by the Free Software Foundation and
 appearing in the LICENSE file included in the packaging of this file.
 In addition, as a special exception, Gilles Debunne gives you certain 
 additional rights, described in the file GPL_EXCEPTION in this package.

 libQGLViewer uses dual licensing. Commercial/proprietary software must
 purchase a libQGLViewer Commercial License.

 This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

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

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


bool SKY::LoadTexture( int side, const QString& 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 );
}