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/*******************************************************************************
* jitter.h
*
* ---------------------------------------------------------------------------
* Persistence of Vision Ray Tracer ('POV-Ray') version 3.7.
* Copyright 1991-2013 Persistence of Vision Raytracer Pty. Ltd.
*
* POV-Ray is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* POV-Ray 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
* ---------------------------------------------------------------------------
* POV-Ray is based on the popular DKB raytracer version 2.12.
* DKBTrace was originally written by David K. Buck.
* DKBTrace Ver 2.0-2.12 were written by David K. Buck & Aaron A. Collins.
* ---------------------------------------------------------------------------
* $File: //depot/public/povray/3.x/source/backend/support/jitter.h $
* $Revision: #1 $
* $Change: 6069 $
* $DateTime: 2013/11/06 11:59:40 $
* $Author: chrisc $
*******************************************************************************/
#ifndef POVRAY_BACKEND_JITTER_H
#define POVRAY_BACKEND_JITTER_H
#include "backend/frame.h"
namespace pov
{
#ifdef DYNAMIC_HASHTABLE
extern unsigned short *hashTable; // GLOBAL VARIABLE
#else
extern ALIGN16 unsigned short hashTable[]; // GLOBAL VARIABLE
#endif
extern const float JitterTable[]; // GLOBAL VARIABLE
inline DBL Jitter2d(int x, int y)
{
return JitterTable[int(hashTable[int(hashTable[int(x & 0xfff)] ^ y) & 0xfff]) & 0xff];
}
inline void Jitter2d(int x, int y, DBL& jx, DBL& jy)
{
jx = JitterTable[int(hashTable[int(hashTable[int((x + 1021) & 0xfff)] ^ (y + 1019)) & 0xfff]) & 0xff]; // Note that 1019 and 1021 are prime! [trf]
jy = JitterTable[int(hashTable[int(hashTable[int((x + 1019) & 0xfff)] ^ (y + 1021)) & 0xfff]) & 0xff]; // Note that 1019 and 1021 are prime! [trf]
}
inline DBL Jitter2d(DBL x, DBL y)
{
return JitterTable[int(hashTable[int(hashTable[(int(x * 1021.0) & 0xfff)] ^ int(y * 1021.0)) & 0xfff]) & 0xff]; // Note that 1021 is prime! [trf]
}
inline void Jitter2d(DBL x, DBL y, DBL& jx, DBL& jy)
{
jx = JitterTable[int(hashTable[int(hashTable[(int(x * 1021.0) & 0xfff)] ^ int(y * 1019.0)) & 0xfff]) & 0xff]; // Note that 1019 and 1021 are prime! [trf]
jy = JitterTable[int(hashTable[int(hashTable[(int(x * 1019.0) & 0xfff)] ^ int(y * 1021.0)) & 0xfff]) & 0xff]; // Note that 1019 and 1021 are prime! [trf]
}
}
#endif // POVRAY_BACKEND_JITTER_H
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