//
//  Filename         : OccluderSource.h
//  Author(s)        : Alexander Beels
//  Purpose          : Class to define a cell grid surrounding
//                     the projected image of a scene
//  Date of creation : 2010-12-21
//
///////////////////////////////////////////////////////////////////////////////


//
//  Copyright (C) : Please refer to the COPYRIGHT file distributed 
//   with this source distribution. 
//
//  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, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//
///////////////////////////////////////////////////////////////////////////////

#include "OccluderSource.h"
#include <algorithm>

OccluderSource::OccluderSource (const GridHelpers::Transform& t, WingedEdge& we) : wingedEdge(we), valid(false), transform(t) {
	begin();
}

OccluderSource::~OccluderSource() {
}

void OccluderSource::buildCachedPolygon() {
	vector<Vec3r> vertices(GridHelpers::enumerateVertices((*currentFace)->getEdgeList()));
	// This doesn't work, because our functor's polymorphism won't survive the copy:
	// std::transform(vertices.begin(), vertices.end(), vertices.begin(), transform);
	// so we have to do:
	for ( vector<Vec3r>::iterator i = vertices.begin(); i != vertices.end(); ++i ) {
		(*i) = transform(*i);
	}
	cachedPolygon = Polygon3r(vertices, transform((*currentFace)->GetNormal()));
}

void OccluderSource::begin() {
 	vector<WShape*>& wshapes = wingedEdge.getWShapes();
	currentShape = wshapes.begin();
	shapesEnd = wshapes.end();
	valid = false;
	if ( currentShape != shapesEnd ) {
		vector<WFace*>& wFaces = (*currentShape)->GetFaceList();
		currentFace = wFaces.begin();
		facesEnd = wFaces.end();

		if ( currentFace != facesEnd ) {
			buildCachedPolygon();
			valid = true;
		}
	}
}

bool OccluderSource::next() {
	if ( valid ) {
		++currentFace;
		while ( currentFace == facesEnd ) {
			++currentShape;
			if ( currentShape == shapesEnd ) {
				valid = false;
				return false;
			} else {
				vector<WFace*>& wFaces = (*currentShape)->GetFaceList();
				currentFace = wFaces.begin();
				facesEnd = wFaces.end();
			}
		}
		buildCachedPolygon();
		return true;
	}
	return false;
}

bool OccluderSource::isValid() {
	// Or:
	// return currentShapes != shapesEnd && currentFace != facesEnd;
	return valid;
}

WFace* OccluderSource::getWFace() {
	return valid ? *currentFace : NULL;
}

Polygon3r OccluderSource::getCameraSpacePolygon() {
	return Polygon3r(GridHelpers::enumerateVertices((*currentFace)->getEdgeList()), (*currentFace)->GetNormal());
}

Polygon3r& OccluderSource::getGridSpacePolygon() {
	return cachedPolygon;
}

void OccluderSource::getOccluderProscenium(real proscenium[4]) {
	begin();
	const Vec3r& initialPoint = cachedPolygon.getVertices()[0];
	proscenium[0] = proscenium[1] = initialPoint[0];
	proscenium[2] = proscenium[3] = initialPoint[1];
	while ( isValid() ) {
		GridHelpers::expandProscenium (proscenium, cachedPolygon);
		next();
	}
	cout << "Proscenium: (" << proscenium[0] << ", " << proscenium[1] << ", " << proscenium[2] << ", " << proscenium[3] << ")" << endl;
}

real OccluderSource::averageOccluderArea() {
	real area = 0.0;
	unsigned numFaces = 0;
	for ( begin(); isValid(); next() ) {
		Vec3r min, max;
		cachedPolygon.getBBox(min, max);
		area += (max[0] - min[0]) * (max[1] - min[1]);
		++numFaces;
	}
	area /= numFaces;
	return area;
}