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

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

 This file is part of the QGLViewer library version 2.3.1.

 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 "tree.h"

using namespace qglviewer;

bool TREE::LoadTexture(const QString& filename )
{
  QImage image;
  if (image.load(filename))
    {
      texture= QGLWidget::convertToGLFormat(image);

      //construire les textures openGL
      glGenTextures( 1, &(texID) );
      glBindTexture( GL_TEXTURE_2D, (texID) );

      glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
      glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR);

      gluBuild2DMipmaps( GL_TEXTURE_2D, GL_RGBA, texture.width(), texture.height(),
			 GL_RGBA, GL_UNSIGNED_BYTE, texture.bits() );
    }
  else
    {
      printf(" treetexture failed\n");
      return false;
    }
  return true;
}


void TREE::initTrees(QUADTREE ter, int num, float waterLevel)
{
  int i;
  myTerrain = ter;
  numTrees = num;
  treeInfo = new Vec[numTrees];
  qsrand( QTime::currentTime().elapsed() );
  for (i=0;i<numTrees;i++)
    {
      do {
	treeInfo[i].setValue(rand( )%myTerrain.sizeHeightMap,
			     rand( )%myTerrain.sizeHeightMap,
			     rand()%myTerrain.sizeHeightMap*treeSizeFactor/myTerrain.sizeHeightMap);
      } while (myTerrain.GetScaledHeightAtPoint((int)treeInfo[i].x,(int)treeInfo[i].y) <= waterLevel);
    }
}

void TREE::Render()
{
  float dim;
  int i;
  glDisable(GL_LIGHTING);

  glAlphaFunc(GL_GREATER, 0.5);	//on enleve automatiquement les pixels de la texture marques "transparent"
  glEnable(GL_ALPHA_TEST);

  glEnable( GL_TEXTURE_2D );

  for (i=0;i<numTrees;i++)
    {
      //on place l'arbre a une hauteur reduit de 5%, car les surface n'ont souvent pas l'hauteur exact et
      // .. les arbres ont tendance a "voler" dans l'air...
      glPushMatrix( );

      glTranslatef( treeInfo[i].x/myTerrain.sizeHeightMap,
		    myTerrain.GetScaledHeightAtPoint((int)treeInfo[i].x,
						     (int)treeInfo[i].y)/myTerrain.sizeHeightMap*0.99,
		    treeInfo[i].y/myTerrain.sizeHeightMap);
      dim = treeInfo[i].z;
      glBindTexture( GL_TEXTURE_2D, texID);
      glBegin( GL_TRIANGLE_FAN );
      glTexCoord2f( 1.0f, 1.0f ); glVertex3f( dim, dim,0 );
      glTexCoord2f( 1.0f, 0.0f ); glVertex3f( dim, 0,0 );
      glTexCoord2f( 0.0f, 0.0f ); glVertex3f( 0, 0,0 );
      glTexCoord2f( 0.0f, 1.0f ); glVertex3f( 0, dim,0 );
      glEnd( );
      glBindTexture( GL_TEXTURE_2D, texID);
      glBegin( GL_TRIANGLE_FAN );
      glTexCoord2f( 1.0f, 1.0f ); glVertex3f( dim/2, dim,-dim/2 );
      glTexCoord2f( 1.0f, 0.0f ); glVertex3f( dim/2, 0,-dim/2 );
      glTexCoord2f( 0.0f, 0.0f ); glVertex3f( dim/2, 0,dim/2 );
      glTexCoord2f( 0.0f, 1.0f ); glVertex3f( dim/2, dim,dim/2 );
      glEnd( );

      glPopMatrix( );
    }


  glDisable(GL_ALPHA_TEST);
}