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

 Copyright (c) 2009, Charles McGarvey
 All rights reserved.
 
 Redistribution   and   use  in  source  and  binary  forms,  with  or  without
 modification, are permitted provided that the following conditions are met:
 
   * Redistributions  of  source  code  must retain the above copyright notice,
     this list of conditions and the following disclaimer.
   * Redistributions  in binary form must reproduce the above copyright notice,
     this  list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.
 
 THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 DAMAGES  (INCLUDING,  BUT  NOT  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES;  LOSS  OF  USE,  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 CAUSED  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 OR  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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

#include "Camera.hh"
#include "Log.hh"
#include "Octree.hh"
	

namespace Mf {


void Octree::sort()
{
	stlplus::ntree<OctreeNode>::prefix_iterator it;

	for (it = tree_.prefix_begin(); it != tree_.prefix_end(); ++it)
	{
		it->sort();
	}
}


OctreeNodeP Octree::insert(EntityP entity, OctreeNodeP node)
{
	ASSERT(node.valid() && "invalid node passed");
	ASSERT(entity && "null entity passed");

	int octantNum = -1;

	Plane::Halfspace halfspace;

	// TODO this method needs a lot of work
	Plane xy = node->getAabb().getPlaneXY();


	// make sure the entity is fully inside the volume
	if (!(entity->getAabb().max[0] < node->getAabb().max[0] &&
			entity->getAabb().min[0] > node->getAabb().min[0] &&
			entity->getAabb().max[1] < node->getAabb().max[1] &&
			entity->getAabb().min[1] > node->getAabb().min[1] &&
			entity->getAabb().max[2] < node->getAabb().max[2] &&
			entity->getAabb().min[2] > node->getAabb().min[2]))
	{
		// TODO this check is only needed for the root node, if we're inside the
		// volume of the root node, we'll be fully inside the child as
		// determined by trying to insert the parent node
		goto done;
	}

	halfspace = xy.intersects(entity->getSphere());
	if (halfspace == Plane::INTERSECT)
	{
		halfspace = xy.intersects(entity->getAabb());
	}

	if (halfspace == Plane::POSITIVE)
	{
		Plane xz = node->getAabb().getPlaneXZ();
		halfspace = xz.intersects(entity->getSphere());
		if (halfspace == Plane::INTERSECT)
		{
			halfspace = xz.intersects(entity->getAabb());
		}

		if (halfspace == Plane::POSITIVE)
		{
			Plane yz = node->getAabb().getPlaneYZ();
			halfspace = yz.intersects(entity->getSphere());
			if (halfspace == Plane::INTERSECT)
			{
				halfspace = yz.intersects(entity->getAabb());
			}

			if (halfspace == Plane::POSITIVE)
			{
				octantNum = 2;
			}
			else if (halfspace == Plane::NEGATIVE)
			{
				octantNum = 3;
			}
		}
		else if (halfspace == Plane::NEGATIVE)
		{
			Plane yz = node->getAabb().getPlaneYZ();
			halfspace = yz.intersects(entity->getSphere());
			if (halfspace == Plane::INTERSECT)
			{
				halfspace = yz.intersects(entity->getAabb());
			}

			if (halfspace == Plane::POSITIVE)
			{
				octantNum = 1;
			}
			else if (halfspace == Plane::NEGATIVE)
			{
				octantNum = 0;
			}
		}
	}
	else if (halfspace == Plane::NEGATIVE)
	{
		Plane xz = node->getAabb().getPlaneXZ();
		halfspace = xz.intersects(entity->getSphere());
		if (halfspace == Plane::INTERSECT)
		{
			halfspace = xz.intersects(entity->getAabb());
		}

		if (halfspace == Plane::POSITIVE)
		{
			Plane yz = node->getAabb().getPlaneYZ();
			halfspace = yz.intersects(entity->getSphere());
			if (halfspace == Plane::INTERSECT)
			{
				halfspace = yz.intersects(entity->getAabb());
			}

			if (halfspace == Plane::POSITIVE)
			{
				octantNum = 6;
			}
			else if (halfspace == Plane::NEGATIVE)
			{
				octantNum = 7;
			}
		}
		else if (halfspace == Plane::NEGATIVE)
		{
			Plane yz = node->getAabb().getPlaneYZ();
			halfspace = yz.intersects(entity->getSphere());
			if (halfspace == Plane::INTERSECT)
			{
				halfspace = yz.intersects(entity->getAabb());
			}

			if (halfspace == Plane::POSITIVE)
			{
				octantNum = 5;
			}
			else if (halfspace == Plane::NEGATIVE)
			{
				octantNum = 4;
			}
		}
	}

done:

	if (octantNum == -1)
	{
		node->objects.push_front(entity);
		return node;
	}
	else
	{
		if ((int)tree_.children(node) <= octantNum)
		{
			addChild(node, octantNum);
		}

		OctreeNodeP child = tree_.child(node, octantNum);
		ASSERT(child.valid() && "expected valid child node");

		return insert(entity, child);
	}
}

OctreeNodeP Octree::reinsert(EntityP entity, OctreeNodeP node)
{
	ASSERT(entity && "null entity passed");
	ASSERT(node.valid() && "invalid node passed");

	std::list<EntityP>::iterator it;
	it = std::find(node->objects.begin(), node->objects.end(), entity);

	if (it != node->objects.end())
	{
		node->objects.erase(it);
	}

	return insert(entity);
}


void Octree::addChild(OctreeNodeP node, int index)
{
	ASSERT(node.valid() && "invalid node passed");

	Aabb octant;

	for (int i = tree_.children(node); i <= index; ++i)
	{
		node->getAabb().getOctant(octant, i);
		tree_.append(node, octant);
	}
}


void Octree::draw(Scalar alpha, OctreeNodeP node)
{
	ASSERT(node.valid() && "invalid node passed");

	node->draw(alpha);

	for (unsigned i = 0; i < tree_.children(node); ++i)
	{
		OctreeNodeP child = tree_.child(node, i);
		ASSERT(child.valid() && "expected valid child node");

		draw(alpha, child);
	}
}

void Octree::drawIfVisible(Scalar alpha, const Camera& cam, OctreeNodeP node)
{
	ASSERT(node.valid() && "invalid node passed");

	// try to cull by sphere
	Frustum::Collision collision =
		cam.getFrustum().contains(node->getSphere());
	if (collision == Frustum::OUTSIDE) return;

	// try to cull by aabb
	collision = cam.getFrustum().contains(node->getAabb());
	if (collision == Frustum::OUTSIDE) return;


	if (collision == Frustum::INSIDE)
	{
		node->draw(alpha);
	}
	else // collision == Frustum::INTERSECT
	{
		node->drawIfVisible(alpha, cam);
	}

	if (tree_.children(node) > 0)
	{
		if (collision == Frustum::INSIDE)
		{
			for (unsigned i = 0; i < tree_.children(node); ++i)
			{
				OctreeNodeP child = tree_.child(node, i);
				ASSERT(child.valid() && "expected valid child node");

				draw(alpha, child);
			}
		}
		else // collision == Frustum::INTERSECT
		{
			for (unsigned i = 0; i < tree_.children(node); ++i)
			{
				OctreeNodeP child = tree_.child(node, i);
				ASSERT(child.valid() && "expected valid child node");

				drawIfVisible(alpha, cam, child);
			}
		}
	}
}


} // namespace Mf

/** vim: set ts=4 sw=4 tw=80: *************************************************/