TeslaRel410/CODE/RP/MUNGA/BOXLIST.CPP

//===========================================================================//
// File:	boxlist.cc                                                          //
// Project: MUNGA           Brick: Spatializer Library                       //
// Contents: Implementation details of bounding-box based spatialization     //
//---------------------------------------------------------------------------//
//   Date    Who  Modification                                               //
// --------  ---  ---------------------------------------------------------- //
// 01/08/95  JMA  Initial port back to C++                                   //
//---------------------------------------------------------------------------//
// Copyright (C) 1993-1995, Virtual World Entertainment, Inc.                //
// All Rights reserved worldwide                                             //
// This unpublished sourcecode is PROPRIETARY and CONFIDENTIAL               //
//===========================================================================//

#include <munga.hpp>
#pragma hdrstop

#if !defined(BOXLIST_HPP)
#	include <boxlist.hpp>
#endif

//#############################################################################
//#########################    BoundingBoxListNode    #########################
//#############################################################################

MemoryBlock
	BoundingBoxListNode::AllocatedMemory(
		sizeof(BoundingBoxListNode),
		500,
		50,
      "BoundingBoxList Nodes"
	);

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
Logical
	BoundingBoxListNode::TestInstance() const
{
	return True;
}

//#############################################################################
//###########################    BoundingBoxList    ###########################
//#############################################################################

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
BoundingBoxList::BoundingBoxList()
{
	root = NULL;
	nodeCount = 0;
	scoreBoard = NULL;
	boundingBoxIndex = NULL;
	isXMajorAxis = True;
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
BoundingBoxList::~BoundingBoxList()
{
	if (scoreBoard)
	{
		Unregister_Pointer(scoreBoard);
		delete scoreBoard;
	}
	if (boundingBoxIndex)
	{
		Unregister_Pointer(boundingBoxIndex);
		delete boundingBoxIndex;
	}
	EraseList();
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
void
	BoundingBoxList::Add(
		BoundingBox* volume,
		const ExtentBox &slice
	)
{
	Check(this);
	Check(volume);

	++nodeCount;
	BoundingBoxListNode *node = new BoundingBoxListNode(volume, slice);
	Register_Object(node);
	node->previousNode = root;
	root = node;
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
void
	BoundingBoxList::Remove(BoundingBox* volume)
{
	Check(this);
	Check(volume);

	//
	//--------------------------------------------------------------------------
	// Spin through all the boxes until we find the one we are after or until we
	// run off the list
	//--------------------------------------------------------------------------
	//
	BoundingBoxListNode
		*p = NULL,
		*c = root;
	while (c)
	{
		Check(c);
		if (c->boundingBox == volume)
		{
			break;
		}
		p = c;
		c = c->previousNode;
	}

	//
	//----------------------------------------------
	// Unlink the node from the list if it was found
	//----------------------------------------------
	//
	if (!c)
	{
		return;
	}

	Check(c);
	if (p)
	{
		Check(p);
		p->previousNode = c->previousNode;
	}
	else
	{
		root = c->previousNode;
	}

	//
	//-----------------
	// Delete this node
	//-----------------
	//
	--nodeCount;
	Unregister_Object(c);
	delete c;
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
void
	BoundingBoxList::EraseList()
{
	Check(this);

	//
	//-----------------------------
	// Delete each node in the list
	//-----------------------------
	//
	BoundingBoxListNode *p = root;
	while (p)
	{
		Check(p);
		BoundingBoxListNode *q = p;
		p = p->previousNode;
		Unregister_Object(q);
		delete q;
	}
	root = NULL;
   nodeCount = 0;
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
BoundingBox*
	BoundingBoxList::FindBoundingBoxContaining(const Point3D &point)
{
	Check(this);
	Check(&point);

	//
	//--------------------------------------------------------------------------
	// Spin through each of the boxes in reverse order until we find a box which
	// contains the specified point.  It will be default have priority over any
	// boxes put in before it
	//--------------------------------------------------------------------------
	//
	for (BoundingBoxListNode *p=root; p; p = p->previousNode)
	{
		Check(p);
		BoundingBox *box = p->boundingBox;
		Check(box);
		if (box->Contains(point))
		{
			return box;
		}
	}
	return NULL;
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
void
	BoundingBoxList::FindBoundingBoxesContaining(
		BoundingBox *volume,
		BoundingBoxCollisionList &list
	)
{
	Check(this);
	Check(volume);
	Check(&list);

	//
	//-------------------------------------------------------------
	// Spin through each of the boxes in reverse order, looking for
	// intesections between the test volume and the box list
	//-------------------------------------------------------------
	//
	for (BoundingBoxListNode *p=root; p; p = p->previousNode)
	{
		Check(p);
		BoundingBox *box = p->boundingBox;
		Check(box);
		if (box->ExtentBox::Intersects(*volume))
		{
			//
			//----------------------------------------------------------------
			// Build the intersection slice, and make sure that it really does
			// intersect the list box
			//----------------------------------------------------------------
			//
			ExtentBox slice;
			slice.Intersect(*volume, *box);
			if (box->IntersectsBounded(slice))
			{

				//
				//------------------------------------------------------------
				// It intersects, so add this to the list.  If we are out of
				// collisions in the list, we are finished detecting, and just
				// return
				//------------------------------------------------------------
				//
				Verify(list.collisionsLeft);
				list.AddCollisionToList(box, slice);
				if (!list.collisionsLeft)
				{
					return;
				}
			}
		}
	}
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
BoundingBox*
	BoundingBoxList::FindBoundingBoxUnder(
		const Point3D &point,
		Scalar *height
	)
{
	Check(this);
	Check(&point);
	Check_Pointer(height);

	//
	//-----------------------------------------------------------------------
	// Spin through each of the bounding boxes, keeping track of which box is
	// hit after the shortest distance
	//-----------------------------------------------------------------------
	//
	BoundingBox *best_box = NULL;
	*height = -1.0f;
	for (BoundingBoxListNode *p=root; p; p = p->previousNode)
	{
		Check(p);
		BoundingBox *box = p->boundingBox;
		Check(box);

		Scalar h = box->FindDistanceBelow(point);
		if (h != -1.0f)
		{
			if (!best_box || *height > h)
			{
				best_box = box;
				*height = h;
			}
		}
	}
	return best_box;
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
BoundingBox*
	BoundingBoxList::FindBoundingBoxHitBy(Line *line)
{
	//
	//-----------------------------------------------------------------------
	// Spin through each of the boxes, letting each box in turn clip the line
	// lengths
	//-----------------------------------------------------------------------
	//
	BoundingBox *best_box = NULL;
	for (BoundingBoxListNode *p=root; p; p = p->previousNode)
	{
		Check(p);
		BoundingBox *box = p->boundingBox;
		Check(box);

		Logical h = box->HitBy(line);
		if (h)
		{
			best_box = box;
		}
	}
	return best_box;
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
Logical
	BoundingBoxList::TestInstance() const
{
	return True;
}