/*-------------------------------------------------------------------------------------
Copyright (c) 2006 John Judnich

This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
-------------------------------------------------------------------------------------*/

#ifndef __RandomTable_H__
#define __RandomTable_H__

#include <OgrePrerequisites.h>
#include <OgreMath.h>

#include <time.h> // for time
#include "MersenneTwister.h"

// random table class that speeds up PG a bit
class RandomTable
{
public:
	RandomTable(unsigned long size=0x8000);
	~RandomTable();

	void resetRandomIndex();
	float getUnitRandom();
	float getRangeRandom(float start, float end);

protected:
	unsigned long tableSize;
	float *table;
	unsigned long customRandomIndex;

	void generateRandomNumbers();	
};


// implementation below
inline RandomTable::RandomTable(unsigned long size) : tableSize(size), table(0), customRandomIndex(0)
{
	table = (float *)malloc(sizeof(float) * tableSize);
	generateRandomNumbers();
}

inline RandomTable::~RandomTable()
{
	if(table)
	{
		free(table);
		table=0;
	}
}

inline void RandomTable::resetRandomIndex()
{
	customRandomIndex = 0;
}

inline float RandomTable::getUnitRandom()
{
	// prevent against overflow
	if(customRandomIndex > tableSize - 1)
		customRandomIndex = 0;
	return table[customRandomIndex++];
}

inline float RandomTable::getRangeRandom(float start, float end)
{
	return (start + ((end - start) * getUnitRandom()));
}

inline void RandomTable::generateRandomNumbers()
{
#ifdef USE_OGRE_RANDOM
	// using ogre's Random
	//srand(0xFACE);
#ifdef WIN32
	srand(GetTickCount());
#else
	srand(time(NULL));
#endif
	for(unsigned long i = 0; i < tableSize; i++)
		table[i] = Ogre::Math::UnitRandom();
#else
	// using our Mersenne Twister (preferred way)
#ifdef WIN32
	MTRand mtrand(GetTickCount());
#else
	MTRand mtrand(time(NULL));
#endif
	for(unsigned long i = 0; i < tableSize; i++)
		table[i] = mtrand.rand();
#endif //USE_OGRE_RANDOM
}

#endif // __RandomTable_H__

