Cinder

include/cinder/Rand.h

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/*
 Copyright (c) 2010, The Barbarian Group
 All rights reserved.

 Redistribution and use in source and binary forms, with or without modification, are permitted provided that
 the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, this list of conditions and
    the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
    the following disclaimer in the documentation and/or other materials provided with the distribution.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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*/

#pragma once

#include <boost/random.hpp>
#include <boost/random/uniform_int.hpp>
#include <boost/random/uniform_real.hpp>
#include <boost/random/mersenne_twister.hpp>

#include "cinder/Vector.h"

namespace cinder {  
    
class Rand {
 public:
    Rand()
        : mBase( 214u ), mFloatGen( mBase, boost::uniform_real<float>( 0.0f, 1.0f ) ), mIntGen( mBase, boost::uniform_int<>( 0, 2147483647 ) )
    {}
    
    Rand( uint32_t seed )
        : mBase( seed ), mFloatGen( mBase, boost::uniform_real<float>( 0.0f, 1.0f ) ), mIntGen( mBase, boost::uniform_int<>( 0, 2147483647 ) )
    {}
    
    bool nextBool()
    {
        return mIntGen() & 1;
    }
    
    int32_t nextInt()
    {
        return mIntGen();
    }
    
    int32_t nextInt( int32_t v )
    {
        return mIntGen() % v;
    }
    
    int32_t nextInt( int32_t a, int32_t b )
    {
        return nextInt( b - a ) + a;
    }
    
    float nextFloat()
    {
        return mFloatGen();
    }
    
    float nextFloat( float v )
    {
        return mFloatGen() * v;
    }
    
    float nextFloat( float a, float b )
    {
        return mFloatGen() * ( b - a ) + a;
    }
    
    float posNegFloat( float a, float b )
    {
        if( nextBool() )
            return nextFloat( a, b );
        else
            return -nextFloat( a, b );
    }
    
    Vec3f nextVec3f()
    {
        float phi = nextFloat( (float)M_PI * 2.0f );
        float costheta = nextFloat( -1.0f, 1.0f );
        
        float rho = math<float>::sqrt( 1.0f - costheta * costheta ); 
        float x = rho * math<float>::cos( phi );
        float y = rho * math<float>::sin( phi );
        float z = costheta;
        
        return Vec3f( x, y, z );
    }

    Vec2f nextVec2f( )
    {
        float theta = nextFloat( (float)M_PI * 2.0f );
        return Vec2f( math<float>::cos( theta ), math<float>::sin( theta ) );
    }
    
    // STATICS
    static void randomize();
    
    static bool randBool()
    {
        return sIntGen() & 1;
    }
    
    static int32_t randInt()
    {
        return sIntGen();
    }
    
    static int32_t randInt( int32_t v )
    {
        if( v == 0 ) return 0;
        else return sIntGen() % v;
    }
    
    static int32_t randInt( int32_t a, int32_t b )
    {
        return randInt( b - a ) + a;
    }
    
    static float randFloat()
    {
        return sFloatGen();
    }
    
    static float randFloat( float v )
    {
        return sFloatGen() * v;
    }
    
    static float randFloat( float a, float b )
    {
        return sFloatGen() * ( b - a ) + a;
    }
    
    static float randPosNegFloat( float a, float b )
    {
        if( randBool() )
            return randFloat( a, b );
        else
            return -randFloat( a, b );
    }
    
    static Vec3f randVec3f()
    {
        float phi = randFloat( (float)M_PI * 2.0f );
        float costheta = randFloat( -1.0f, 1.0f );
        
        float rho = math<float>::sqrt( 1.0f - costheta * costheta ); 
        float x = rho * math<float>::cos( phi );
        float y = rho * math<float>::sin( phi );
        float z = costheta;
        
        return Vec3f( x, y, z );
    }

    static Vec2f randVec2f()
    {
        float theta = randFloat( (float)M_PI * 2.0f );
        return Vec2f( math<float>::cos( theta ), math<float>::sin( theta ) );
    }
    
private:
    boost::mt19937 mBase;
    boost::variate_generator<boost::mt19937&, boost::uniform_real<float> > mFloatGen;   
    boost::variate_generator<boost::mt19937&, boost::uniform_int<> > mIntGen;

    static boost::mt19937 sBase;
    static boost::variate_generator<boost::mt19937&, boost::uniform_real<float> > sFloatGen;
    static boost::variate_generator<boost::mt19937&, boost::uniform_int<> > sIntGen;
};

} // namespace cinder