//////////////////////////////////////////////////////////////////////////////////
// OpenGL Mathematics Copyright (c) 2005 - 2010 G-Truc Creation (www.g-truc.net)
//////////////////////////////////////////////////////////////////////////////////
// Created : 2006-01-16
// Updated : 2006-01-16
// Licence : This source is under MIT License
// File    : glm/gtx/random.inl
//////////////////////////////////////////////////////////////////////////////////

#include <ctime>
#include <cassert>

namespace glm{
namespace gtx{
namespace random
{
    template <>
	inline float signedRand1()
	{
		#if(GLM_COMPILER & GLM_COMPILER_VC)
		#define RAND_SHIFT_NUM 5
		#else
		#define RAND_SHIFT_NUM 0
		#endif
		return float((std::rand() - (RAND_MAX >> 1) - 1) << 1) / float(RAND_MAX - RAND_SHIFT_NUM);
	}

    template <>
	inline double signedRand1()
	{
		return double(signedRand1<float>());
	}

	template <typename T>
	inline detail::tvec2<T> signedRand2()
	{
		return detail::tvec2<T>(
			signedRand1<float>(),
			signedRand1<float>());
	}

	template <typename T>
	inline detail::tvec3<T> signedRand3()
	{
		return detail::tvec3<T>(
			signedRand1<float>(),
			signedRand1<float>(),
			signedRand1<float>());
	}

	template <typename T>
	inline detail::tvec4<T> signedRand4()
	{
		return detail::tvec4<T>(
			signedRand1<float>(),
			signedRand1<float>(),
			signedRand1<float>(),
			signedRand1<float>());
	}

    template <typename T>
    inline detail::tvec2<T> normalizedRand2()
    {
        T a = compRand1<T>(T(0), T(6.283185307179586476925286766559f));
        return detail::tvec2<T>(cos(a), sin(a));
    }

	template <typename T>
    inline detail::tvec3<T> normalizedRand3()
    {
	    T z = compRand1(T(-1), T(1));
	    T a = compRand1(T(0), T(6.283185307179586476925286766559f));

        T r = sqrt(T(1) - z * z);

	    T x = r * cos(a);
	    T y = r * sin(a);

        return detail::tvec3<T>(x, y, z);
    }

    template <typename T>
    inline detail::tvec3<T> normalizedRand3(
		T Min, 
		T Max)
    {
        return normalizedRand3<T>() * compRand1(Min, Max);
    }

	template <>
	inline float compRand1()
	{
		return float(std::rand()) / float(RAND_MAX);
	}

	template <>
	inline double compRand1()
	{
		return double(std::rand()) / double(RAND_MAX);
	}

	inline glm::half compRand1(
		glm::half Min, 
		glm::half Max)
	{
		return compRand1<glm::half>() * (Max - Min) + Min;
	}

	inline float compRand1(
		float Min, 
		float Max)
	{
		return compRand1<float>() * (Max - Min) + Min;
	}

	inline double compRand1(
		double Min, 
		double Max)
	{
		return compRand1<double>() * (Max - Min) + Min;
	}

	template <typename T>
	inline T compRand1(
		T Min, 
		T Max)
	{
		return T(compRand1<double>() * double(Max - Min) + double(Min));
	}

	template <typename T>
	inline detail::tvec2<T> compRand2(
		T Min, 
		T Max)
	{
		return detail::tvec2<T>(
			compRand1(Min, Max),
			compRand1(Min, Max));
	}

	template <typename T>
	inline detail::tvec3<T> compRand3(
		T Min, 
		T Max)
	{
		return detail::tvec3<T>(
			compRand1(Min, Max),
			compRand1(Min, Max),
			compRand1(Min, Max));
	}

	template <typename T>
	inline detail::tvec4<T> compRand4(
		T Min, 
		T Max)
	{
		return detail::tvec4<T>(
			compRand1(Min, Max),
			compRand1(Min, Max),
			compRand1(Min, Max),
			compRand1(Min, Max));
	}

	template <typename T>
	inline detail::tvec2<T> compRand2(
		T Min, 
		const detail::tvec2<T>& Max)
	{
		return detail::tvec2<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y));
	}

	template <typename T>
	inline detail::tvec3<T> compRand3(
		T Min, 
		const detail::tvec3<T>& Max)
	{
		return detail::tvec3<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y),
			compRand1(Min.z, Max.z));
	}

	template <typename T>
	inline detail::tvec4<T> compRand4(
		T Min, 
		const detail::tvec4<T>& Max)
	{
		return detail::tvec4<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y),
			compRand1(Min.z, Max.z),
			compRand1(Min.w, Max.w));
	}

	template <typename T>
	inline detail::tvec2<T> compRand2(
		const detail::tvec2<T>& Min, 
		T Max)
	{
		return detail::tvec2<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y));
	}

	template <typename T>
	inline detail::tvec3<T> compRand3(
		const detail::tvec3<T>& Min, 
		T Max)
	{
		return detail::tvec3<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y),
			compRand1(Min.z, Max.z));
	}

	template <typename T>
	inline detail::tvec4<T> compRand4(
		const detail::tvec4<T>& Min, 
		T Max)
	{
		return detail::tvec4<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y),
			compRand1(Min.z, Max.z),
			compRand1(Min.w, Max.w));
	}

	template <typename T>
	inline detail::tvec2<T> compRand2(
		const detail::tvec2<T>& Min, 
		const detail::tvec2<T>& Max)
	{
		return detail::tvec2<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y));
	}

	template <typename T>
	inline detail::tvec3<T> compRand3(
		const detail::tvec3<T>& Min, 
		const detail::tvec3<T>& Max)
	{
		return detail::tvec3<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y),
			compRand1(Min.z, Max.z));
	}

	template <typename T>
	inline detail::tvec4<T> compRand4(
		const detail::tvec4<T>& Min, 
		const detail::tvec4<T>& Max)
	{
		return detail::tvec4<T>(
			compRand1(Min.x, Max.x),
			compRand1(Min.y, Max.y),
			compRand1(Min.z, Max.z),
			compRand1(Min.w, Max.w));
	}

	template <typename T>
    inline detail::tvec2<float> vecRand2()
    {
		detail::tvec2<float> result(float(0));
		do
		{
			result = compRand2(float(-1), float(1));
		} while (length(result) > float(1));

        return result;
    }

	template <typename T>
    inline detail::tvec2<double> vecRand2()
    {
		detail::tvec2<double> result(double(0));
		do
		{
			result = compRand2(double(-1), double(1));
		} while (length(result) > double(1));

        return result;
    }

	template <typename T>
    inline detail::tvec2<T> vecRand2(
		T MinRadius, 
		T MaxRadius)
    {
		assert(MinRadius <= MaxRadius);

		detail::tvec2<T> Result(T(0));
		T LenRadius(0);

		do
		{
			Result = compRand2(-MaxRadius, MaxRadius);
			LenRadius = length(Result);
		}
		while(LenRadius > MaxRadius || LenRadius < MinRadius);

        return Result;
    }

	template <typename T>
    inline detail::tvec3<T> vecRand3()
    {
		detail::tvec3<T> Result(T(0));
		do
		{
			Result = compRand3(T(-1), T(1));
		}
		while(length(Result) > T(1));

        return Result;
    }

	template <typename T>
    inline detail::tvec3<T> vecRand3(
		T MinRadius, 
		T MaxRadius)
    {
		assert(MinRadius <= MaxRadius);

		detail::tvec3<T> Result(0);
		T LenRadius(0);

		do
		{
			Result = compRand3(-MaxRadius, MaxRadius);
			LenRadius = length(Result);
		}
		while(LenRadius > MaxRadius || LenRadius < MinRadius);

        return Result;
    }

	template <typename T>
    inline detail::tvec4<float> vecRand4()
    {
		detail::tvec4<float> result(float(0));
		do
		{
			result = compRand4(float(-1), float(1));
		} while (length(result) > float(1));

        return result;
    }

	template <typename T>
    inline detail::tvec4<double> vecRand4()
    {
		detail::tvec4<double> result(double(0));
		do
		{
			result = compRand4(double(-1), double(1));
		} while (length(result) > double(1));

        return result;
    }

	template <typename T>
    inline detail::tvec4<T> vecRand4(
		T MinRadius, 
		T MaxRadius)
    {
		assert(MinRadius <= MaxRadius);

		detail::tvec4<T> Result(T(0));
		T LenRadius(T(0));

		do
		{
			Result = compRand4(-MaxRadius, MaxRadius);
			LenRadius = length(Result);
		}
		while(LenRadius > MaxRadius || LenRadius < MinRadius);

        return Result;
    }

    template <typename T>
    inline T gaussRand1(
		T mean, 
		T std_deviation)
    {
        T w, x1, x2;

        do
        {
            x1 = compRand1(T(-1), T(1));
            x2 = compRand1(T(-1), T(1));

            w = x1 * x1 + x2 * x2;
        } while(w > T(1));

        return x2 * std_deviation * std_deviation * sqrt((T(-2) * log(w)) / w) + mean;
    }

    template <typename T>
    inline detail::tvec2<T> gaussRand2(
		T mean, 
		T std_deviation)
    {
        return detail::tvec2<T>(
            gaussRand1(mean, std_deviation),
            gaussRand1(mean, std_deviation));
    }

    template <typename T>
    inline detail::tvec3<T> gaussRand3(
		T mean, 
		T std_deviation)
    {
        return detail::tvec3<T>(
            gaussRand1(mean, std_deviation),
            gaussRand1(mean, std_deviation),
            gaussRand1(mean, std_deviation));
    }

    template <typename T>
    inline detail::tvec4<T> gaussRand4(
		T mean, 
		T std_deviation)
    {
        return detail::tvec4<T>(
            gaussRand1(mean, std_deviation),
            gaussRand1(mean, std_deviation),
            gaussRand1(mean, std_deviation),
            gaussRand1(mean, std_deviation));
    }

    template <typename T>
    inline detail::tvec2<T> gaussRand2(
		T mean, 
		const detail::tvec2<T>& std_deviation)
    {
        return detail::tvec2<T>(
            gaussRand1(mean, std_deviation.x),
            gaussRand1(mean, std_deviation.y));
    }

    template <typename T>
    inline detail::tvec3<T> gaussRand3(
		T mean, 
		const detail::tvec3<T>& std_deviation)
    {
        return detail::tvec3<T>(
            gaussRand1(mean, std_deviation.x),
            gaussRand1(mean, std_deviation.y),
            gaussRand1(mean, std_deviation.z));
    }

    template <typename T>
    inline detail::tvec4<T> gaussRand4(
		T mean, 
		const detail::tvec4<T>& std_deviation)
    {
        return detail::tvec4<T>(
            gaussRand1(mean, std_deviation.x),
            gaussRand1(mean, std_deviation.y),
            gaussRand1(mean, std_deviation.z),
            gaussRand1(mean, std_deviation.w));
    }

    template <typename T>
    inline detail::tvec2<T> gaussRand2(
		const detail::tvec2<T>& mean, 
		T std_deviation)
    {
        return detail::tvec2<T>(
            gaussRand1(mean.x, std_deviation),
            gaussRand1(mean.y, std_deviation));
    }

    template <typename T>
    inline detail::tvec3<T> gaussRand3(
		const detail::tvec3<T>& mean, 
		T std_deviation)
    {
        return detail::tvec3<T>(
            gaussRand1(mean.x, std_deviation),
            gaussRand1(mean.y, std_deviation),
            gaussRand1(mean.z, std_deviation));
    }

    template <typename T>
    inline detail::tvec4<T> gaussRand4(
		const detail::tvec4<T>& mean, 
		T std_deviation)
    {
        return detail::tvec4<T>(
            gaussRand1(mean.x, std_deviation),
            gaussRand1(mean.y, std_deviation),
            gaussRand1(mean.z, std_deviation),
            gaussRand1(mean.w, std_deviation));
    }

    template <typename T>
    inline detail::tvec2<T> gaussRand2(
		const detail::tvec2<T>& mean, 
		const detail::tvec2<T>& std_deviation)
    {
        return detail::tvec2<T>(
            gaussRand1(mean.x, std_deviation.x),
            gaussRand1(mean.y, std_deviation.y));
    }

    template <typename T>
    inline detail::tvec3<T> gaussRand3(
		const detail::tvec3<T>& mean, 
		const detail::tvec3<T>& std_deviation)
    {
        return detail::tvec3<T>(
            gaussRand1(mean.x, std_deviation.x),
            gaussRand1(mean.y, std_deviation.y),
            gaussRand1(mean.z, std_deviation.z));
    }

    template <typename T>
    inline detail::tvec4<T> gaussRand4(
		const detail::tvec4<T>& mean, 
		const detail::tvec4<T>& std_deviation)
    {
        return detail::tvec4<T>(
            gaussRand1(mean.x, std_deviation.x),
            gaussRand1(mean.y, std_deviation.y),
            gaussRand1(mean.z, std_deviation.z),
            gaussRand1(mean.w, std_deviation.w));
    }

}//namespace random
}//namespace gtx
}//namespace glm
