## Introduction ##

Nethrar is an attempt at a strict and somewhat faithful reproduction of the
portal behavior found in Minecraft Survival Single Player (SSP) for the Bukkit
mod plugin system, with some extensions. Don't ask about the name.

Portals are created with a direct spatial mapping from normal world coordinates
to Nether world coordinates. Portals create a small air pocket and platform
when first created, excepting obsidian blocks. So, a portal that is on solid
ground in the normal world may create a portal in mid-air in the nether, and a
portal from the Nether may appear underwater in the normal world. Portals will
not create themselves in configurations which are otherwise invalid in SSP, such
as two portals directly face-to-face adjacent. Other valid configurations may
not appear, however no directly contradictory configuration should appear.
Portals from the Nether to the real world also follow an extremely conservative
approach to generating new portals. A portal newly entered from the Nether will
check all areas of them normal world for a portal that would link to said portal
in the Nether. It will then choose the closest one to link to, and teleport the
player to that portal.

Portals currently operate under the "as if it were a door" policy - walking
through the portal should be like walking through a door. Your facing and
momentum should be preserved. So, if you walk into a portal straight-on, you
should exit facing away. If you back into a portal, you should exit facing the
portal. Similarly, momentum is preserved. If you ride a minecart into a portal,
the minecart preserves momentum through the portal.

## Building ##

This assumes your system has a sensible Java installation and appropriate path
settings. Adapt these instructions as needed for your system.

1) Download a copy of Bukkit/CraftBukkit from http://wiki.bukkit.org/Main_Page
   to somewhere on your filesystem.
2) Edit the BUKKIT_API variable in Makefile.generic to point to the jar file you
   downloaded.
3) make -f Makefile.generic
4) Install the resulting .jar file and config.yml into the plugins/ directory
   of your CraftBukkit server as normal.

## Misc comments ##

Note that due to a flaw in how minecarts are spawned it is necessary to spawn a
new minecart with a y-value 1 higher than the one which entered the portal to
avoid it falling into (as opposed to onto) the floor on the other side of the
portal. A y value of only +.11 is sufficient if there are rails on the other
side of the portal, but not if there are none.

## License ##

Copyright (C) 2011 Andrew Krieger

Ths program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.