/* -*- C++ -*-
 * Copyright ©2004 Hugo Mills <hugo@carfax.org.uk>
 *
 * This software is distributed under the terms of the GNU GPL v3
 * For more information on the GPL, see the file COPYING or 
 * visit http://www.gnu.org/
 *
 * This software is distributed without warranty
 */

#include "xfmap_planarequidistant.h"

extern "C" PluginInfo* getmodules(int i)
{
	if(i==0)
	{
		PluginInfo_Map* pi = new PluginInfo_Map();

		pi->name = "Planar Equidistant";
		pi->author = "Hugo Mills";
		pi->copyright = "©2005 Hugo Mills";
		pi->version = 0x10000;
		pi->parser = XfMap_PlanarEquidistant::parser;
		return pi;
	}
	else
		return NULL;
}

XfMap* XfMap_PlanarEquidistant::parser(
	ConfigLexer* lex,
	const std::string& type,
	const std::string& subtype
	)
{
	if(type != "planar")
		return NULL;
	if(subtype != "equidistant")
		return NULL;

	double limit = 180.0;

	while(!lex->eos()) {
		if(!readkeyedvalue(lex, "limit", &limit))
			throw(UnknownConfigToken(lex));
	}
	
	return new XfMap_PlanarEquidistant(degrad(limit));
}

bool XfMap_PlanarEquidistant::f(dvec2& result, const dvec3& pos) const
{
	double r = acos(pos[2]);
	if(r > limit)
		return false;
	double xyr = sqrt(pos[0]*pos[0] + pos[1]*pos[1]);
	double m = r / xyr / M_PI;

	result[0] = m * pos[0];
	result[1] = m * pos[1];

	return true;
}

bool XfMap_PlanarEquidistant::g(dvec3& result, const dvec2& pos) const
{
	double r = sqrt(pos[0]*pos[0] + pos[1]*pos[1]);
	if(r * M_PI > limit)
		return false;

	result[2] = cos(r * M_PI);
	double z2 = sqrt(1-result[2]*result[2]);
	double m;
	if(r == 0.0)
		m = 0;
	else
		m = z2 / r;

	result[0] = m * pos[0];
	result[1] = m * pos[1];

	return true;
}