Half.h

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/*********************************************************\
 *  File: Half.h                                         *
 *
 *  Copyright (C) 2002-2012 The PixelLight Team (http://www.pixellight.org/)
 *
 *  This file is part of PixelLight.
 *
 *  PixelLight is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  PixelLight 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with PixelLight. If not, see <http://www.gnu.org/licenses/>.
\*********************************************************/


#ifndef __PLMATH_HALF_H__
#define __PLMATH_HALF_H__
#pragma once


//[-------------------------------------------------------]
//[ Includes                                              ]
//[-------------------------------------------------------]
#include "PLMath/PLMath.h"


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
namespace PLMath {


//[-------------------------------------------------------]
//[ Classes                                               ]
//[-------------------------------------------------------]
/**
*  @brief
*    Static helper class for the half data type (16 bit floating point)
*
*  @note
*    - This class is using information from "Fast Half Float Conversions" (ftp://ftp.fox-toolkit.org/pub/fasthalffloatconversion.pdf)
*      written by Jeroen van der Zijp, November 2008 (Revised September 2010)
*    - OpenEXR IlmBase 1.0.2 (Modified BSD License)
*/
class Half {


    //[-------------------------------------------------------]
    //[ Public static data                                    ]
    //[-------------------------------------------------------]
    public:
        // Some half numbers
        static PLMATH_API const PLCore::uint16 Zero;                /**< Representation of 0.0 */
        static PLMATH_API const PLCore::uint16 One;                 /**< Representation of 1.0 */

        // Important values
        static PLMATH_API const float SmallestPositive;             /**< Smallest positive half (5.96046448e-08f) */
        static PLMATH_API const float SmallestPositiveNormalized;   /**< Smallest positive normalized half (6.10351562e-05f) */
        static PLMATH_API const float LargestPositive;              /**< Largest positive half (65504.0f) */
        static PLMATH_API const float Epsilon;                      /**< Smallest positive epsilon for which 1+e!=1 (0.00097656f) */


    //[-------------------------------------------------------]
    //[ Public functions                                      ]
    //[-------------------------------------------------------]
    public:
        /**
        *  @brief
        *    Returns whether or not the given half value is zero
        *
        *  @param[in] nHalf
        *    Half value to check
        *
        *  @return
        *    'true' if the given half value is zero, else 'false'
        */
        static inline bool IsZero(PLCore::uint16 nHalf);

        /**
        *  @brief
        *    Returns whether or not the given half value is negative
        *
        *  @param[in] nHalf
        *    Half value to check
        *
        *  @return
        *    'true' if the given half value is negative, else 'false'
        */
        static inline bool IsNegative(PLCore::uint16 nHalf);

        /**
        *  @brief
        *    Returns whether or not the given half value is not a number (NAN)
        *
        *  @param[in] nHalf
        *    Half value to check
        *
        *  @return
        *    'true' if the given half value is not a number, else 'false'
        */
        static inline bool IsNotANumber(PLCore::uint16 nHalf);

        /**
        *  @brief
        *    Returns whether or not the given half value is finite
        *
        *  @param[in] nHalf
        *    Half value to check
        *
        *  @return
        *    'true' if the given half value is finite, else 'false'
        */
        static inline bool IsFinite(PLCore::uint16 nHalf);

        /**
        *  @brief
        *    Returns whether or not the given half value is infinity
        *
        *  @param[in] nHalf
        *    Half value to check
        *
        *  @return
        *    'true' if the given half value is infinity, else 'false'
        */
        static inline bool IsInfinity(PLCore::uint16 nHalf);

        /**
        *  @brief
        *    Returns whether or not the given half value is normalized
        *
        *  @param[in] nHalf
        *    Half value to check
        *
        *  @return
        *    'true' if the given half value is normalized, else 'false'
        */
        static inline bool IsNormalized(PLCore::uint16 nHalf);

        /**
        *  @brief
        *    Returns whether or not the given half value is de-normalized
        *
        *  @param[in] nHalf
        *    Half value to check
        *
        *  @return
        *    'true' if the given half value is de-normalized, else 'false'
        */
        static inline bool IsDenormalized(PLCore::uint16 nHalf);

        /**
        *  @brief
        *    Converts a given half value into a float value
        *
        *  @param[in] nHalf
        *    Half value to convert
        *
        *  @return
        *    The given half value as float
        */
        static PLMATH_API float ToFloat(PLCore::uint16 nHalf);

        /**
        *  @brief
        *    Converts a given float value into a half value
        *
        *  @param[in] fFloat
        *    Float value to convert
        *
        *  @return
        *    The given float value as half
        */
        static PLMATH_API PLCore::uint16 FromFloat(float fFloat);


};


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
} // PLMath


//[-------------------------------------------------------]
//[ Implementation                                        ]
//[-------------------------------------------------------]
#include "PLMath/Half.inl"


#endif // __PLMATH_HALF_H__