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/**
* @file llrand.h
* @brief Some useful math functions.
*
* Copyright (c) 2000-2007, Linden Research, Inc.
*
* The source code in this file ("Source Code") is provided by Linden Lab
* to you under the terms of the GNU General Public License, version 2.0
* ("GPL"), unless you have obtained a separate licensing agreement
* ("Other License"), formally executed by you and Linden Lab. Terms of
* the GPL can be found in doc/GPL-license.txt in this distribution, or
* online at http://secondlife.com/developers/opensource/gplv2
*
* There are special exceptions to the terms and conditions of the GPL as
* it is applied to this Source Code. View the full text of the exception
* in the file doc/FLOSS-exception.txt in this software distribution, or
* online at http://secondlife.com/developers/opensource/flossexception
*
* By copying, modifying or distributing this software, you acknowledge
* that you have read and understood your obligations described above,
* and agree to abide by those obligations.
*
* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
* COMPLETENESS OR PERFORMANCE.
*/
#ifndef LL_LLRAND_H
#define LL_LLRAND_H
// As long as you #include "llviewerprecompiledheaders.h",
// you can use "gLindenLabRandomNumber.llfrand( range );" which returns a
// random number F32 ranging from 0.0f to range.
// -Ventrella - Sept 30, 2005
// Slams Intel processors into Single Precision FP mode
// (which is not any faster on modern hardware)
void slamFPCW( void );
class LLRand
{
public:
LLRand(U32 seed) : mSeed(seed) {}
~LLRand() {}
void seed(U32 seed) { mSeed = seed; }
U32 llrand()
{
mSeed = U64L(1664525) * mSeed + U64L(1013904223);
return (U32)mSeed;
}
U32 llrand(U32 val)
{
mSeed = U64L(1664525) * mSeed + U64L(1013904223);
return (U32)(mSeed) % val;
}
// val is the maximum
F32 llfrand(F32 val)
{
const U32 FP_ONE = 0x3f800000;
const U32 FP_MASK = 0x007fffff;
U32 ir = llrand();
ir = FP_ONE | (FP_MASK & ir);
// generate random float
F32 fr = (*(F32 *)&ir);
// correct to [0..1)
fr -= 1.f;
fr *= val;
return fr;
}
public:
U64 mSeed;
};
F32 frand(F32 val);
extern LLRand gLindenLabRandomNumber;
#endif
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