qgschunkloader_p.cpp

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/***************************************************************************
  qgschunkloader_p.cpp
  --------------------------------------
  Date                 : October 2020
  Copyright            : (C) 2020 by Martin Dobias
  Email                : wonder dot sk at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   This program 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.                                   *
 *                                                                         *
 ***************************************************************************/
 
#include "qgschunkloader_p.h"
 
#include "qgschunknode_p.h"
#include <QVector>
 
QgsQuadtreeChunkLoaderFactory::QgsQuadtreeChunkLoaderFactory() = default;
 
QgsQuadtreeChunkLoaderFactory::~QgsQuadtreeChunkLoaderFactory() = default;
 
void QgsQuadtreeChunkLoaderFactory::setupQuadtree( const QgsAABB &rootBbox, float rootError, int maxLevel )
{
  mRootBbox = rootBbox;
  mRootError = rootError;
  mMaxLevel = maxLevel;
}
 
QgsChunkNode *QgsQuadtreeChunkLoaderFactory::createRootNode() const
{
  return new QgsChunkNode( QgsChunkNodeId( 0, 0, 0 ), mRootBbox, mRootError );
}
 
QVector<QgsChunkNode *> QgsQuadtreeChunkLoaderFactory::createChildren( QgsChunkNode *node ) const
{
  QVector<QgsChunkNode *> children;
 
  if ( node->level() >= mMaxLevel )
    return children;
 
  QgsChunkNodeId nodeId = node->tileId();
  float childError = node->error() / 2;
  QgsAABB bbox = node->bbox();
  float xc = bbox.xCenter(), zc = bbox.zCenter();
 
  for ( int i = 0; i < 4; ++i )
  {
    int dx = i & 1, dy = !!( i & 2 );
    QgsChunkNodeId childId( nodeId.d + 1, nodeId.x * 2 + dx, nodeId.y * 2 + ( dy ? 0 : 1 ) );  // TODO: inverse dy?
    // the Y and Z coordinates below are intentionally flipped, because
    // in chunk node IDs the X,Y axes define horizontal plane,
    // while in our 3D scene the X,Z axes define the horizontal plane
    float chXMin = dx ? xc : bbox.xMin;
    float chXMax = dx ? bbox.xMax : xc;
    float chZMin = dy ? zc : bbox.zMin;
    float chZMax = dy ? bbox.zMax : zc;
    float chYMin = bbox.yMin;
    float chYMax = bbox.yMax;
    children << new QgsChunkNode( childId, QgsAABB( chXMin, chYMin, chZMin, chXMax, chYMax, chZMax ), childError, node );
  }
  return children;
}