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/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
* Copyright (C) 2015-2016 Mario Luzeiro <mrluzeiro@ua.pt>
* Copyright (C) 1992-2016 KiCad Developers, see AUTHORS.txt for contributors.
*
* 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, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
/**
* @file mortoncodes.cpp
* @brief Implementes Morton Codes base on the implementation of Fabian “ryg” Giesen
* https://fgiesen.wordpress.com/2009/12/13/decoding-morton-codes/
*/
#include "mortoncodes.h"
// "Insert" a 0 bit after each of the 16 low bits of x
uint32_t Part1By1( uint32_t x )
{
x &= 0x0000ffff; // x = ---- ---- ---- ---- fedc ba98 7654 3210
x = (x ^ (x << 8)) & 0x00ff00ff; // x = ---- ---- fedc ba98 ---- ---- 7654 3210
x = (x ^ (x << 4)) & 0x0f0f0f0f; // x = ---- fedc ---- ba98 ---- 7654 ---- 3210
x = (x ^ (x << 2)) & 0x33333333; // x = --fe --dc --ba --98 --76 --54 --32 --10
x = (x ^ (x << 1)) & 0x55555555; // x = -f-e -d-c -b-a -9-8 -7-6 -5-4 -3-2 -1-0
return x;
}
// "Insert" two 0 bits after each of the 10 low bits of x
uint32_t Part1By2( uint32_t x )
{
x &= 0x000003ff; // x = ---- ---- ---- ---- ---- --98 7654 3210
x = (x ^ (x << 16)) & 0xff0000ff; // x = ---- --98 ---- ---- ---- ---- 7654 3210
x = (x ^ (x << 8)) & 0x0300f00f; // x = ---- --98 ---- ---- 7654 ---- ---- 3210
x = (x ^ (x << 4)) & 0x030c30c3; // x = ---- --98 ---- 76-- --54 ---- 32-- --10
x = (x ^ (x << 2)) & 0x09249249; // x = ---- 9--8 --7- -6-- 5--4 --3- -2-- 1--0
return x;
}
// Inverse of Part1By1 - "delete" all odd-indexed bits
uint32_t Compact1By1( uint32_t x )
{
x &= 0x55555555; // x = -f-e -d-c -b-a -9-8 -7-6 -5-4 -3-2 -1-0
x = (x ^ (x >> 1)) & 0x33333333; // x = --fe --dc --ba --98 --76 --54 --32 --10
x = (x ^ (x >> 2)) & 0x0f0f0f0f; // x = ---- fedc ---- ba98 ---- 7654 ---- 3210
x = (x ^ (x >> 4)) & 0x00ff00ff; // x = ---- ---- fedc ba98 ---- ---- 7654 3210
x = (x ^ (x >> 8)) & 0x0000ffff; // x = ---- ---- ---- ---- fedc ba98 7654 3210
return x;
}
// Inverse of Part1By2 - "delete" all bits not at positions divisible by 3
uint32_t Compact1By2( uint32_t x )
{
x &= 0x09249249; // x = ---- 9--8 --7- -6-- 5--4 --3- -2-- 1--0
x = (x ^ (x >> 2)) & 0x030c30c3; // x = ---- --98 ---- 76-- --54 ---- 32-- --10
x = (x ^ (x >> 4)) & 0x0300f00f; // x = ---- --98 ---- ---- 7654 ---- ---- 3210
x = (x ^ (x >> 8)) & 0xff0000ff; // x = ---- --98 ---- ---- ---- ---- 7654 3210
x = (x ^ (x >> 16)) & 0x000003ff; // x = ---- ---- ---- ---- ---- --98 7654 3210
return x;
}
uint32_t EncodeMorton2( uint32_t x, uint32_t y )
{
return ( Part1By1( y ) << 1 ) + Part1By1( x );
}
uint32_t EncodeMorton3( uint32_t x, uint32_t y, uint32_t z )
{
return ( Part1By2( z ) << 2 ) + ( Part1By2( y ) << 1 ) + Part1By2( x );
}
uint32_t DecodeMorton2X( uint32_t code )
{
return Compact1By1( code >> 0 );
}
uint32_t DecodeMorton2Y( uint32_t code )
{
return Compact1By1( code >> 1 );
}
uint32_t DecodeMorton3X( uint32_t code )
{
return Compact1By2( code >> 0 );
}
uint32_t DecodeMorton3Y( uint32_t code )
{
return Compact1By2( code >> 1 );
}
uint32_t DecodeMorton3Z( uint32_t code )
{
return Compact1By2( code >> 2 );
}
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