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/*==LICENSE==*
CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011 Cyan Worlds, Inc.
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 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
You can contact Cyan Worlds, Inc. by email legal@cyan.com
or by snail mail at:
Cyan Worlds, Inc.
14617 N Newport Hwy
Mead, WA 99021
*==LICENSE==*/
/*****************************************************************************
*
* $/Plasma20/Sources/Plasma/NucleusLib/pnUtils/Private/pnUtRand.cpp
*
***/
#include "../Pch.h"
#pragma hdrstop
/*****************************************************************************
*
* Private
*
***/
class RandomContext {
dword m_seed;
dword m_value;
void UpdateValue ();
public:
RandomContext ();
void Reset ();
void SetSeed (unsigned seed);
float GetFloat ();
float GetFloat (float minVal, float maxVal);
unsigned GetUnsigned ();
unsigned GetUnsigned (unsigned minVal, unsigned maxVal);
};
/*****************************************************************************
*
* Private data
*
***/
static const dword kDefaultRandomSeed = 0x075bd924;
static RandomContext s_random;
/*****************************************************************************
*
* RandomContext
*
***/
//============================================================================
RandomContext::RandomContext ()
: m_seed(kDefaultRandomSeed)
{
Reset();
}
//============================================================================
void RandomContext::UpdateValue () {
const dword A = 0xbc8f;
const dword Q = 0xadc8;
const dword R = 0x0d47;
dword div = m_value / Q;
m_value = A * (m_value - Q * div) - R * div;
if (m_value > kRandomMax)
m_value -= kRandomMax + 1;
if (!m_value)
m_value = kDefaultRandomSeed;
}
//============================================================================
void RandomContext::Reset () {
m_value = m_seed;
}
//============================================================================
void RandomContext::SetSeed (unsigned seed) {
// Never allow a seed of zero
m_seed = seed ? seed : kDefaultRandomSeed;
Reset();
}
//============================================================================
float RandomContext::GetFloat () {
UpdateValue();
return m_value * (1.0f / kRandomMax);
}
//============================================================================
float RandomContext::GetFloat (float minVal, float maxVal) {
float value = GetFloat();
return minVal + value * (maxVal - minVal);
}
//============================================================================
unsigned RandomContext::GetUnsigned () {
UpdateValue();
return (unsigned)m_value;
}
//============================================================================
unsigned RandomContext::GetUnsigned (unsigned minVal, unsigned maxVal) {
unsigned value = GetUnsigned();
return minVal + value % (maxVal - minVal + 1);
}
/*****************************************************************************
*
* Exports
*
***/
//============================================================================
void RandReset () {
s_random.Reset();
}
//============================================================================
void RandSetSeed (unsigned seed) {
s_random.SetSeed(seed);
}
//============================================================================
float RandFloat () {
return s_random.GetFloat();
}
//============================================================================
float RandFloat (float minVal, float maxVal) {
return s_random.GetFloat(minVal, maxVal);
}
//============================================================================
unsigned RandUnsigned () {
return s_random.GetUnsigned();
}
//============================================================================
unsigned RandUnsigned (unsigned minVal, unsigned maxVal) {
return s_random.GetUnsigned(minVal, maxVal);
}