container_2d.cpp

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2015-2016 Mario Luzeiro <[email protected]>
 * Copyright (C) 2015-2020 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * 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.
 *
 * This program 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 this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include "container_2d.h"
#include "../ray.h"
#include <boost/range/algorithm/partition.hpp>
#include <boost/range/algorithm/nth_element.hpp>
#include <wx/debug.h>


CONTAINER_2D_BASE::CONTAINER_2D_BASE( OBJECT_2D_TYPE aObjType )
{
 m_bbox.Reset();
}


void CONTAINER_2D_BASE::Clear()
{
 std::lock_guard<std::mutex> lock( m_lock );
 m_bbox.Reset();

 for( LIST_OBJECT2D::iterator ii = m_objects.begin(); ii != m_objects.end(); ++ii )
 {
 delete *ii;
 }

 m_objects.clear();
}


CONTAINER_2D_BASE::~CONTAINER_2D_BASE()
{
 Clear();
}


CONTAINER_2D::CONTAINER_2D() : CONTAINER_2D_BASE( OBJECT_2D_TYPE::CONTAINER )
{

}


void CONTAINER_2D::GetIntersectingObjects( const BBOX_2D& aBBox,
 CONST_LIST_OBJECT2D& aOutList ) const
{
}


bool CONTAINER_2D::IntersectAny( const RAYSEG2D& aSegRay ) const
{
 return false;
}


BVH_CONTAINER_2D::BVH_CONTAINER_2D() : CONTAINER_2D_BASE( OBJECT_2D_TYPE::BVHCONTAINER )
{
 m_isInitialized = false;
 m_bbox.Reset();
 m_elementsToDelete.clear();
 m_tree = nullptr;
}


void BVH_CONTAINER_2D::Clear()
{
 CONTAINER_2D_BASE::Clear();
 destroy();
}


void BVH_CONTAINER_2D::destroy()
{
 for( std::list<BVH_CONTAINER_NODE_2D*>::iterator ii = m_elementsToDelete.begin();
 ii != m_elementsToDelete.end();
 ++ii )
 {
 delete *ii;
 }

 m_elementsToDelete.clear();
 m_tree = nullptr;
 m_isInitialized = false;
}


BVH_CONTAINER_2D::~BVH_CONTAINER_2D()
{
 destroy();
}


#define BVH_CONTAINER2D_MAX_OBJ_PER_LEAF 4


void BVH_CONTAINER_2D::BuildBVH()
{
 if( m_isInitialized )
 destroy();

 m_isInitialized = true;

 if( m_objects.empty() )
 {
 return;
 }

 m_tree = new BVH_CONTAINER_NODE_2D;

 m_elementsToDelete.push_back( m_tree );
 m_tree->m_BBox = m_bbox;

 for( LIST_OBJECT2D::const_iterator ii = m_objects.begin(); ii != m_objects.end(); ++ii )
 {
 m_tree->m_LeafList.push_back( static_cast<const OBJECT_2D*>( *ii ) );
 }

 recursiveBuild_MIDDLE_SPLIT( m_tree );
}


// Based on a blog post by VADIM KRAVCENKO
// http://www.vadimkravcenko.com/bvh-tree-building
// Implements:

// "Split in the middle of the longest Axis"
// "Creates a binary tree with Top-Down approach.
// Fastest BVH building, but least [speed] accuracy."
static bool sortByCentroidX( const OBJECT_2D* a, const OBJECT_2D* b )
{
 return a->GetCentroid()[0] < b->GetCentroid()[0];
}


static bool sortByCentroidY( const OBJECT_2D* a, const OBJECT_2D* b )
{
 return a->GetCentroid()[0] < b->GetCentroid()[0];
}


static bool sortByCentroidZ( const OBJECT_2D* a, const OBJECT_2D* b )
{
 return a->GetCentroid()[0] < b->GetCentroid()[0];
}


void BVH_CONTAINER_2D::recursiveBuild_MIDDLE_SPLIT( BVH_CONTAINER_NODE_2D* aNodeParent )
{
 wxASSERT( aNodeParent != nullptr );
 wxASSERT( aNodeParent->m_BBox.IsInitialized() == true );
 wxASSERT( aNodeParent->m_LeafList.size() > 0 );

 if( aNodeParent->m_LeafList.size() > BVH_CONTAINER2D_MAX_OBJ_PER_LEAF )
 {
 // Create Leaf Nodes
 BVH_CONTAINER_NODE_2D* leftNode = new BVH_CONTAINER_NODE_2D;
 BVH_CONTAINER_NODE_2D* rightNode = new BVH_CONTAINER_NODE_2D;
 m_elementsToDelete.push_back( leftNode );
 m_elementsToDelete.push_back( rightNode );

 leftNode->m_BBox.Reset();
 rightNode->m_BBox.Reset();
 leftNode->m_LeafList.clear();
 rightNode->m_LeafList.clear();

 // Decide which axis to split
 const unsigned int axis_to_split = aNodeParent->m_BBox.MaxDimension();

 // Divide the objects
 switch( axis_to_split )
 {
 case 0: aNodeParent->m_LeafList.sort( sortByCentroidX ); break;
 case 1: aNodeParent->m_LeafList.sort( sortByCentroidY ); break;
 case 2: aNodeParent->m_LeafList.sort( sortByCentroidZ ); break;
 }

 unsigned int i = 0;

 for( CONST_LIST_OBJECT2D::const_iterator ii = aNodeParent->m_LeafList.begin();
 ii != aNodeParent->m_LeafList.end();
 ++ii )
 {
 const OBJECT_2D* object = static_cast<const OBJECT_2D*>( *ii );

 if( i < (aNodeParent->m_LeafList.size() / 2 ) )
 {
 leftNode->m_BBox.Union( object->GetBBox() );
 leftNode->m_LeafList.push_back( object );
 }
 else
 {
 rightNode->m_BBox.Union( object->GetBBox() );
 rightNode->m_LeafList.push_back( object );
 }

 i++;
 }

 wxASSERT( leftNode->m_LeafList.size() > 0 );
 wxASSERT( rightNode->m_LeafList.size() > 0 );
 wxASSERT( ( leftNode->m_LeafList.size() + rightNode->m_LeafList.size() ) ==
 aNodeParent->m_LeafList.size() );

 aNodeParent->m_Children[0] = leftNode;
 aNodeParent->m_Children[1] = rightNode;
 aNodeParent->m_LeafList.clear();

 recursiveBuild_MIDDLE_SPLIT( leftNode );
 recursiveBuild_MIDDLE_SPLIT( rightNode );

 wxASSERT( aNodeParent->m_LeafList.size() == 0 );
 }
 else
 {
 // It is a Leaf
 aNodeParent->m_Children[0] = nullptr;
 aNodeParent->m_Children[1] = nullptr;
 }

 wxASSERT( aNodeParent != nullptr );
 wxASSERT( aNodeParent->m_BBox.IsInitialized() == true );
}


bool BVH_CONTAINER_2D::IntersectAny( const RAYSEG2D& aSegRay ) const
{
 wxASSERT( m_isInitialized == true );

 if( m_tree )
 return recursiveIntersectAny( m_tree, aSegRay );

 return false;
}


bool BVH_CONTAINER_2D::recursiveIntersectAny( const BVH_CONTAINER_NODE_2D* aNode,
 const RAYSEG2D& aSegRay ) const
{
 wxASSERT( aNode != nullptr );

 if( aNode->m_BBox.Inside( aSegRay.m_Start ) || aNode->m_BBox.Inside( aSegRay.m_End ) ||
 aNode->m_BBox.Intersect( aSegRay ) )
 {
 if( !aNode->m_LeafList.empty() )
 {
 wxASSERT( aNode->m_Children[0] == nullptr );
 wxASSERT( aNode->m_Children[1] == nullptr );

 // Leaf
 for( const OBJECT_2D* obj : aNode->m_LeafList )
 {
 if( obj->IsPointInside( aSegRay.m_Start ) ||
 obj->IsPointInside( aSegRay.m_End ) ||
 obj->Intersect( aSegRay, nullptr, nullptr ) )
 return true;
 }
 }
 else
 {
 wxASSERT( aNode->m_Children[0] != nullptr );
 wxASSERT( aNode->m_Children[1] != nullptr );

 // Node
 if( recursiveIntersectAny( aNode->m_Children[0], aSegRay ) )
 return true;

  if( recursiveIntersectAny( aNode->m_Children[1], aSegRay ) )
 return true;
 }
 }

 return false;
}


void BVH_CONTAINER_2D::GetIntersectingObjects( const BBOX_2D& aBBox,
 CONST_LIST_OBJECT2D& aOutList ) const
{
 wxASSERT( aBBox.IsInitialized() == true );
 wxASSERT( m_isInitialized == true );

 aOutList.clear();

 if( m_tree )
 recursiveGetListObjectsIntersects( m_tree, aBBox, aOutList );
}


void BVH_CONTAINER_2D::recursiveGetListObjectsIntersects( const BVH_CONTAINER_NODE_2D* aNode,
  const BBOX_2D& aBBox,
 CONST_LIST_OBJECT2D& aOutList ) const
{
 wxASSERT( aNode != nullptr );
 wxASSERT( aBBox.IsInitialized() == true );

 if( aNode->m_BBox.Intersects( aBBox ) )
 {
 if( !aNode->m_LeafList.empty() )
 {
 wxASSERT( aNode->m_Children[0] == nullptr );
 wxASSERT( aNode->m_Children[1] == nullptr );

 // Leaf
 for( CONST_LIST_OBJECT2D::const_iterator ii = aNode->m_LeafList.begin();
 ii != aNode->m_LeafList.end();
 ++ii )
 {
 const OBJECT_2D* obj = static_cast<const OBJECT_2D*>( *ii );

 if( obj->Intersects( aBBox ) )
 aOutList.push_back( obj );
 }
 }
 else
 {
 wxASSERT( aNode->m_Children[0] != nullptr );
 wxASSERT( aNode->m_Children[1] != nullptr );

 // Node
 recursiveGetListObjectsIntersects( aNode->m_Children[0], aBBox, aOutList );
 recursiveGetListObjectsIntersects( aNode->m_Children[1], aBBox, aOutList );
 }
 }
}