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/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
This 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 2.1 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, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "database.h"
#include "irrlichttypes.h"
/****************
* Black magic! *
****************
* The position hashing is very messed up.
* It's a lot more complicated than it looks.
*/
static inline s16 unsigned_to_signed(u16 i, u16 max_positive)
{
if (i < max_positive) {
return i;
} else {
return i - (max_positive * 2);
}
}
// Modulo of a negative number does not work consistently in C
static inline s64 pythonmodulo(s64 i, s16 mod)
{
if (i >= 0) {
return i % mod;
}
return mod - ((-i) % mod);
}
s64 Database::getBlockAsInteger(const v3s16 &pos)
{
return (u64) pos.Z * 0x1000000 +
(u64) pos.Y * 0x1000 +
(u64) pos.X;
}
v3s16 Database::getIntegerAsBlock(s64 i)
{
v3s16 pos;
pos.X = unsigned_to_signed(pythonmodulo(i, 4096), 2048);
i = (i - pos.X) / 4096;
pos.Y = unsigned_to_signed(pythonmodulo(i, 4096), 2048);
i = (i - pos.Y) / 4096;
pos.Z = unsigned_to_signed(pythonmodulo(i, 4096), 2048);
return pos;
}
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