/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2011 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#ifndef __Math_H__
#define __Math_H__

#include "CmPrerequisitesUtil.h"

namespace CamelotFramework
{
	/** \addtogroup Core
	*  @{
	*/
	/** \addtogroup Math
	*  @{
	*/
	/** Wrapper class which indicates a given angle value is in Radians.
    @remarks
        Radian values are interchangeable with Degree values, and conversions
        will be done automatically between them.
    */
	class Radian
	{
		float mRad;

	public:
		explicit Radian ( float r=0 ) : mRad(r) {}
		Radian ( const Degree& d );
		Radian& operator = ( const float& f ) { mRad = f; return *this; }
		Radian& operator = ( const Radian& r ) { mRad = r.mRad; return *this; }
		Radian& operator = ( const Degree& d );

		float valueDegrees() const; // see bottom of this file
		float valueRadians() const { return mRad; }
		float valueAngleUnits() const;

        const Radian& operator + () const { return *this; }
		Radian operator + ( const Radian& r ) const { return Radian ( mRad + r.mRad ); }
		Radian operator + ( const Degree& d ) const;
		Radian& operator += ( const Radian& r ) { mRad += r.mRad; return *this; }
		Radian& operator += ( const Degree& d );
		Radian operator - () const { return Radian(-mRad); }
		Radian operator - ( const Radian& r ) const { return Radian ( mRad - r.mRad ); }
		Radian operator - ( const Degree& d ) const;
		Radian& operator -= ( const Radian& r ) { mRad -= r.mRad; return *this; }
		Radian& operator -= ( const Degree& d );
		Radian operator * ( float f ) const { return Radian ( mRad * f ); }
        Radian operator * ( const Radian& f ) const { return Radian ( mRad * f.mRad ); }
		Radian& operator *= ( float f ) { mRad *= f; return *this; }
		Radian operator / ( float f ) const { return Radian ( mRad / f ); }
		Radian& operator /= ( float f ) { mRad /= f; return *this; }

		bool operator <  ( const Radian& r ) const { return mRad <  r.mRad; }
		bool operator <= ( const Radian& r ) const { return mRad <= r.mRad; }
		bool operator == ( const Radian& r ) const { return mRad == r.mRad; }
		bool operator != ( const Radian& r ) const { return mRad != r.mRad; }
		bool operator >= ( const Radian& r ) const { return mRad >= r.mRad; }
		bool operator >  ( const Radian& r ) const { return mRad >  r.mRad; }

		inline CM_UTILITY_EXPORT friend std::ostream& operator <<
			( std::ostream& o, const Radian& v )
		{
			o << "Radian(" << v.valueRadians() << ")";
			return o;
		}
	};

    /** Wrapper class which indicates a given angle value is in Degrees.
    @remarks
        Degree values are interchangeable with Radian values, and conversions
        will be done automatically between them.
    */
	class Degree
	{
		float mDeg; // if you get an error here - make sure to define/typedef 'float' first

	public:
		explicit Degree ( float d=0 ) : mDeg(d) {}
		Degree ( const Radian& r ) : mDeg(r.valueDegrees()) {}
		Degree& operator = ( const float& f ) { mDeg = f; return *this; }
		Degree& operator = ( const Degree& d ) { mDeg = d.mDeg; return *this; }
		Degree& operator = ( const Radian& r ) { mDeg = r.valueDegrees(); return *this; }

		float valueDegrees() const { return mDeg; }
		float valueRadians() const; // see bottom of this file
		float valueAngleUnits() const;

		const Degree& operator + () const { return *this; }
		Degree operator + ( const Degree& d ) const { return Degree ( mDeg + d.mDeg ); }
		Degree operator + ( const Radian& r ) const { return Degree ( mDeg + r.valueDegrees() ); }
		Degree& operator += ( const Degree& d ) { mDeg += d.mDeg; return *this; }
		Degree& operator += ( const Radian& r ) { mDeg += r.valueDegrees(); return *this; }
		Degree operator - () const { return Degree(-mDeg); }
		Degree operator - ( const Degree& d ) const { return Degree ( mDeg - d.mDeg ); }
		Degree operator - ( const Radian& r ) const { return Degree ( mDeg - r.valueDegrees() ); }
		Degree& operator -= ( const Degree& d ) { mDeg -= d.mDeg; return *this; }
		Degree& operator -= ( const Radian& r ) { mDeg -= r.valueDegrees(); return *this; }
		Degree operator * ( float f ) const { return Degree ( mDeg * f ); }
        Degree operator * ( const Degree& f ) const { return Degree ( mDeg * f.mDeg ); }
		Degree& operator *= ( float f ) { mDeg *= f; return *this; }
		Degree operator / ( float f ) const { return Degree ( mDeg / f ); }
		Degree& operator /= ( float f ) { mDeg /= f; return *this; }

		bool operator <  ( const Degree& d ) const { return mDeg <  d.mDeg; }
		bool operator <= ( const Degree& d ) const { return mDeg <= d.mDeg; }
		bool operator == ( const Degree& d ) const { return mDeg == d.mDeg; }
		bool operator != ( const Degree& d ) const { return mDeg != d.mDeg; }
		bool operator >= ( const Degree& d ) const { return mDeg >= d.mDeg; }
		bool operator >  ( const Degree& d ) const { return mDeg >  d.mDeg; }

		inline CM_UTILITY_EXPORT friend std::ostream& operator <<
			( std::ostream& o, const Degree& v )
		{
			o << "Degree(" << v.valueDegrees() << ")";
			return o;
		}
	};

    /** Wrapper class which identifies a value as the currently default angle 
        type, as defined by Math::setAngleUnit.
    @remarks
        Angle values will be automatically converted between radians and degrees,
        as appropriate.
    */
	class Angle
	{
		float mAngle;
	public:
		explicit Angle ( float angle ) : mAngle(angle) {}
		operator Radian() const;
		operator Degree() const;
	};

	// these functions could not be defined within the class definition of class
	// Radian because they required class Degree to be defined
	inline Radian::Radian ( const Degree& d ) : mRad(d.valueRadians()) {
	}
	inline Radian& Radian::operator = ( const Degree& d ) {
		mRad = d.valueRadians(); return *this;
	}
	inline Radian Radian::operator + ( const Degree& d ) const {
		return Radian ( mRad + d.valueRadians() );
	}
	inline Radian& Radian::operator += ( const Degree& d ) {
		mRad += d.valueRadians();
		return *this;
	}
	inline Radian Radian::operator - ( const Degree& d ) const {
		return Radian ( mRad - d.valueRadians() );
	}
	inline Radian& Radian::operator -= ( const Degree& d ) {
		mRad -= d.valueRadians();
		return *this;
	}

    /** Class to provide access to common mathematical functions.
        @remarks
            Most of the maths functions are aliased versions of the C runtime
            library functions. They are aliased here to provide future
            optimisation opportunities, either from faster RTLs or custom
            math approximations.
        @note
            <br>This is based on MgcMath.h from
            <a href="http://www.geometrictools.com/">Wild Magic</a>.
    */
    class CM_UTILITY_EXPORT Math 
    {
   public:
       /** The angular units used by the API. This functionality is now deprecated in favor
	       of discreet angular unit types ( see Degree and Radian above ). The only place
		   this functionality is actually still used is when parsing files. Search for
		   usage of the Angle class for those instances
       */
       enum AngleUnit
       {
           AU_DEGREE,
           AU_RADIAN
       };

    protected:
       // angle units used by the api
       static AngleUnit msAngleUnit;

        /// Size of the trig tables as determined by constructor.
        static int mTrigTableSize;

        /// Radian -> index factor value ( mTrigTableSize / 2 * PI )
        static float mTrigTableFactor;
        static float* mSinTable;
        static float* mTanTable;

        /** Private function to build trig tables.
        */
        void buildTrigTables();

		static float SinTable (float fValue);
		static float TanTable (float fValue);
    public:
        /** Default constructor.
            @param
                trigTableSize Optional parameter to set the size of the
                tables used to implement Sin, Cos, Tan
        */
        Math(unsigned int trigTableSize = 4096);

        /** Default destructor.
        */
        ~Math();

		static inline float Abs (float fValue) { return float(fabs(fValue)); }
		static inline Degree Abs (const Degree& dValue) { return Degree(fabs(dValue.valueDegrees())); }
		static inline Radian Abs (const Radian& rValue) { return Radian(fabs(rValue.valueRadians())); }
		static Radian ACos (float fValue);
		static Radian ASin (float fValue);
		static inline Radian ATan (float fValue) { return Radian(atan(fValue)); }
		static inline Radian ATan2 (float fY, float fX) { return Radian(atan2(fY,fX)); }
		static inline float Ceil (float fValue) { return float(ceil(fValue)); }
		static inline int CeilToInt (float fValue) { return int(ceil(fValue)); }
		static inline float Round (float fValue) { return floor(fValue + 0.5f); }
		static inline int RoundToInt (float fValue) { return int(floor(fValue + 0.5f)); }
		static inline bool isNaN(float f)
		{
			// std::isnan() is C99, not supported by all compilers
			// However NaN always fails this next test, no other number does.
			return f != f;
		}

        /** Cosine function.
            @param
                fValue Angle in radians
            @param
                useTables If true, uses lookup tables rather than
                calculation - faster but less accurate.
        */
        static inline float Cos (const Radian& fValue, bool useTables = false) {
			return (!useTables) ? float(cos(fValue.valueRadians())) : SinTable(fValue.valueRadians() + HALF_PI);
		}
        /** Cosine function.
            @param
                fValue Angle in radians
            @param
                useTables If true, uses lookup tables rather than
                calculation - faster but less accurate.
        */
        static inline float Cos (float fValue, bool useTables = false) {
			return (!useTables) ? float(cos(fValue)) : SinTable(fValue + HALF_PI);
		}

		static inline float Exp (float fValue) { return float(exp(fValue)); }

		static inline float Floor (float fValue) { return float(floor(fValue)); }

		static inline int FloorToInt (float fValue) { return int(floor(fValue)); }

		static inline float Log (float fValue) { return float(log(fValue)); }

		/// Stored value of log(2) for frequent use
		static const float LOG2;

		static inline float Log2 (float fValue) { return float(log(fValue)/LOG2); }

		static inline float LogN (float base, float fValue) { return float(log(fValue)/log(base)); }

		static inline float Pow (float fBase, float fExponent) { return float(pow(fBase,fExponent)); }

        static float Sign (float fValue);
		static inline Radian Sign ( const Radian& rValue )
		{
			return Radian(Sign(rValue.valueRadians()));
		}
		static inline Degree Sign ( const Degree& dValue )
		{
			return Degree(Sign(dValue.valueDegrees()));
		}

        /** Sine function.
            @param
                fValue Angle in radians
            @param
                useTables If true, uses lookup tables rather than
                calculation - faster but less accurate.
        */
        static inline float Sin (const Radian& fValue, bool useTables = false) {
			return (!useTables) ? float(sin(fValue.valueRadians())) : SinTable(fValue.valueRadians());
		}
        /** Sine function.
            @param
                fValue Angle in radians
            @param
                useTables If true, uses lookup tables rather than
                calculation - faster but less accurate.
        */
        static inline float Sin (float fValue, bool useTables = false) {
			return (!useTables) ? float(sin(fValue)) : SinTable(fValue);
		}

		static inline float Sqr (float fValue) { return fValue*fValue; }

		static inline float Sqrt (float fValue) { return float(sqrt(fValue)); }

        static inline Radian Sqrt (const Radian& fValue) { return Radian(sqrt(fValue.valueRadians())); }

        static inline Degree Sqrt (const Degree& fValue) { return Degree(sqrt(fValue.valueDegrees())); }

        /** Inverse square root i.e. 1 / Sqrt(x), good for vector
            normalisation.
        */
		static float InvSqrt(float fValue);

        static float UnitRandom ();  // in [0,1]

        static float RangeRandom (float fLow, float fHigh);  // in [fLow,fHigh]

        static float SymmetricRandom ();  // in [-1,1]

        /** Tangent function.
            @param
                fValue Angle in radians
            @param
                useTables If true, uses lookup tables rather than
                calculation - faster but less accurate.
        */
		static inline float Tan (const Radian& fValue, bool useTables = false) {
			return (!useTables) ? float(tan(fValue.valueRadians())) : TanTable(fValue.valueRadians());
		}
        /** Tangent function.
            @param
                fValue Angle in radians
            @param
                useTables If true, uses lookup tables rather than
                calculation - faster but less accurate.
        */
		static inline float Tan (float fValue, bool useTables = false) {
			return (!useTables) ? float(tan(fValue)) : TanTable(fValue);
		}

		static inline float DegreesToRadians(float degrees) { return degrees * fDeg2Rad; }
        static inline float RadiansToDegrees(float radians) { return radians * fRad2Deg; }

       /** These functions used to set the assumed angle units (radians or degrees) 
            expected when using the Angle type.
       @par
            You can set this directly after creating a new Root, and also before/after resource creation,
            depending on whether you want the change to affect resource files.
       */
       static void setAngleUnit(AngleUnit unit);
       /** Get the unit being used for angles. */
       static AngleUnit getAngleUnit(void);

       /** Convert from the current AngleUnit to radians. */
       static float AngleUnitsToRadians(float units);
       /** Convert from radians to the current AngleUnit . */
       static float RadiansToAngleUnits(float radians);
       /** Convert from the current AngleUnit to degrees. */
       static float AngleUnitsToDegrees(float units);
       /** Convert from degrees to the current AngleUnit. */
       static float DegreesToAngleUnits(float degrees);

       /** Checks whether a given point is inside a triangle, in a
            2-dimensional (Cartesian) space.
            @remarks
                The vertices of the triangle must be given in either
                trigonometrical (anticlockwise) or inverse trigonometrical
                (clockwise) order.
            @param
                p The point.
            @param
                a The triangle's first vertex.
            @param
                b The triangle's second vertex.
            @param
                c The triangle's third vertex.
            @returns
                If the point resides in the triangle, <b>true</b> is
                returned.
            @par
                If the point is outside the triangle, <b>false</b> is
                returned.
        */
        static bool pointInTri2D(const Vector2& p, const Vector2& a, 
			const Vector2& b, const Vector2& c);

       /** Checks whether a given 3D point is inside a triangle.
       @remarks
            The vertices of the triangle must be given in either
            trigonometrical (anticlockwise) or inverse trigonometrical
            (clockwise) order, and the point must be guaranteed to be in the
			same plane as the triangle
        @param
            p The point.
        @param
            a The triangle's first vertex.
        @param
            b The triangle's second vertex.
        @param
            c The triangle's third vertex.
		@param 
			normal The triangle plane's normal (passed in rather than calculated
				on demand since the caller may already have it)
        @returns
            If the point resides in the triangle, <b>true</b> is
            returned.
        @par
            If the point is outside the triangle, <b>false</b> is
            returned.
        */
        static bool pointInTri3D(const Vector3& p, const Vector3& a, 
			const Vector3& b, const Vector3& c, const Vector3& normal);
        /** Ray / plane intersection, returns boolean result and distance. */
        static std::pair<bool, float> intersects(const Ray& ray, const Plane& plane);

        /** Ray / sphere intersection, returns boolean result and distance. */
        static std::pair<bool, float> intersects(const Ray& ray, const Sphere& sphere, 
            bool discardInside = true);
        
        /** Ray / box intersection, returns boolean result and distance. */
        static std::pair<bool, float> intersects(const Ray& ray, const AABox& box);

        /** Ray / box intersection, returns boolean result and two intersection distance.
        @param
            ray The ray.
        @param
            box The box.
        @param
            d1 A real pointer to retrieve the near intersection distance
                from the ray origin, maybe <b>null</b> which means don't care
                about the near intersection distance.
        @param
            d2 A real pointer to retrieve the far intersection distance
                from the ray origin, maybe <b>null</b> which means don't care
                about the far intersection distance.
        @returns
            If the ray is intersects the box, <b>true</b> is returned, and
            the near intersection distance is return by <i>d1</i>, the
            far intersection distance is return by <i>d2</i>. Guarantee
            <b>0</b> <= <i>d1</i> <= <i>d2</i>.
        @par
            If the ray isn't intersects the box, <b>false</b> is returned, and
            <i>d1</i> and <i>d2</i> is unmodified.
        */
        static bool intersects(const Ray& ray, const AABox& box,
            float* d1, float* d2);

        /** Ray / triangle intersection, returns boolean result and distance.
        @param
            ray The ray.
        @param
            a The triangle's first vertex.
        @param
            b The triangle's second vertex.
        @param
            c The triangle's third vertex.
		@param 
			normal The triangle plane's normal (passed in rather than calculated
				on demand since the caller may already have it), doesn't need
                normalised since we don't care.
        @param
            positiveSide Intersect with "positive side" of the triangle
        @param
            negativeSide Intersect with "negative side" of the triangle
        @returns
            If the ray is intersects the triangle, a pair of <b>true</b> and the
            distance between intersection point and ray origin returned.
        @par
            If the ray isn't intersects the triangle, a pair of <b>false</b> and
            <b>0</b> returned.
        */
        static std::pair<bool, float> intersects(const Ray& ray, const Vector3& a,
            const Vector3& b, const Vector3& c, const Vector3& normal,
            bool positiveSide = true, bool negativeSide = true);

        /** Ray / triangle intersection, returns boolean result and distance.
        @param
            ray The ray.
        @param
            a The triangle's first vertex.
        @param
            b The triangle's second vertex.
        @param
            c The triangle's third vertex.
        @param
            positiveSide Intersect with "positive side" of the triangle
        @param
            negativeSide Intersect with "negative side" of the triangle
        @returns
            If the ray is intersects the triangle, a pair of <b>true</b> and the
            distance between intersection point and ray origin returned.
        @par
            If the ray isn't intersects the triangle, a pair of <b>false</b> and
            <b>0</b> returned.
        */
        static std::pair<bool, float> intersects(const Ray& ray, const Vector3& a,
            const Vector3& b, const Vector3& c,
            bool positiveSide = true, bool negativeSide = true);

        /** Sphere / box intersection test. */
        static bool intersects(const Sphere& sphere, const AABox& box);

        /** Plane / box intersection test. */
        static bool intersects(const Plane& plane, const AABox& box);

        /** Ray / convex plane list intersection test. 
        @param ray The ray to test with
        @param plaeList List of planes which form a convex volume
        @param normalIsOutside Does the normal point outside the volume
        */
        static std::pair<bool, float> intersects(
            const Ray& ray, const Vector<Plane>::type& planeList, 
            bool normalIsOutside);
        /** Ray / convex plane list intersection test. 
        @param ray The ray to test with
        @param plaeList List of planes which form a convex volume
        @param normalIsOutside Does the normal point outside the volume
        */
        static std::pair<bool, float> intersects(
            const Ray& ray, const List<Plane>::type& planeList, 
            bool normalIsOutside);

        /** Sphere / plane intersection test. 
        @remarks NB just do a plane.getDistance(sphere.getCenter()) for more detail!
        */
        static bool intersects(const Sphere& sphere, const Plane& plane);

        /** Compare 2 reals, using tolerance for inaccuracies.
        */
        static bool RealEqual(float a, float b,
            float tolerance = std::numeric_limits<float>::epsilon());

        /** Calculates the tangent space vector for a given set of positions / texture coords. */
        static Vector3 calculateTangentSpaceVector(
            const Vector3& position1, const Vector3& position2, const Vector3& position3,
            float u1, float v1, float u2, float v2, float u3, float v3);

        /** Build a reflection matrix for the passed in plane. */
        static Matrix4 buildReflectionMatrix(const Plane& p);
        /** Calculate a face normal, including the w component which is the offset from the origin. */
        static Vector4 calculateFaceNormal(const Vector3& v1, const Vector3& v2, const Vector3& v3);
        /** Calculate a face normal, no w-information. */
        static Vector3 calculateBasicFaceNormal(const Vector3& v1, const Vector3& v2, const Vector3& v3);
        /** Calculate a face normal without normalize, including the w component which is the offset from the origin. */
        static Vector4 calculateFaceNormalWithoutNormalize(const Vector3& v1, const Vector3& v2, const Vector3& v3);
        /** Calculate a face normal without normalize, no w-information. */
        static Vector3 calculateBasicFaceNormalWithoutNormalize(const Vector3& v1, const Vector3& v2, const Vector3& v3);

		/** Generates a value based on the Gaussian (normal) distribution function
			with the given offset and scale parameters.
		*/
		static float gaussianDistribution(float x, float offset = 0.0f, float scale = 1.0f);

		/** Clamp a value within an inclusive range. */
		template <typename T>
		static T Clamp(T val, T minval, T maxval)
		{
			assert (minval <= maxval && "Invalid clamp range");
			return std::max(std::min(val, maxval), minval);
		}

		/** Clamp a value within an inclusive range. */
		template <typename T>
		static T Clamp01(T val)
		{
			return std::max(std::min(val, (T)1), (T)0);
		}

		static Matrix4 makeViewMatrix(const Vector3& position, const Quaternion& orientation, 
			const Matrix4* reflectMatrix = 0);

		/** Get a bounding radius value from a bounding box. */
		static float boundingRadiusFromAABB(const AABox& aabb);



        static const float POS_INFINITY;
        static const float NEG_INFINITY;
        static const float PI;
        static const float TWO_PI;
        static const float HALF_PI;
		static const float fDeg2Rad;
		static const float fRad2Deg;

    };

	// these functions must be defined down here, because they rely on the
	// angle unit conversion functions in class Math:

	inline float Radian::valueDegrees() const
	{
		return Math::RadiansToDegrees ( mRad );
	}

	inline float Radian::valueAngleUnits() const
	{
		return Math::RadiansToAngleUnits ( mRad );
	}

	inline float Degree::valueRadians() const
	{
		return Math::DegreesToRadians ( mDeg );
	}

	inline float Degree::valueAngleUnits() const
	{
		return Math::DegreesToAngleUnits ( mDeg );
	}

	inline Angle::operator Radian() const
	{
		return Radian(Math::AngleUnitsToRadians(mAngle));
	}

	inline Angle::operator Degree() const
	{
		return Degree(Math::AngleUnitsToDegrees(mAngle));
	}

	inline Radian operator * ( float a, const Radian& b )
	{
		return Radian ( a * b.valueRadians() );
	}

	inline Radian operator / ( float a, const Radian& b )
	{
		return Radian ( a / b.valueRadians() );
	}

	inline Degree operator * ( float a, const Degree& b )
	{
		return Degree ( a * b.valueDegrees() );
	}

	inline Degree operator / ( float a, const Degree& b )
	{
		return Degree ( a / b.valueDegrees() );
	}
	/** @} */
	/** @} */

}
#endif