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Added powerOfTwo functions

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This commit is contained in:
Christophe Riccio 2014-10-27 19:07:23 +01:00
parent f09d1fd3d4
commit 0de2f5c587
2 changed files with 161 additions and 0 deletions
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58
glm/gtx/bit.hpp
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@ -45,3 +45,61 @@
#if(defined(GLM_MESSAGES))
# pragma message("GLM: GLM_GTX_bit extension is deprecated, include GLM_GTC_bitfield and GLM_GTC_integer instead")
#endif
namespace glm
{
/// @addtogroup gtx_bit
/// @{
/// @see gtx_bit
template <typename genIUType>
GLM_FUNC_DECL genIUType highestBitValue(genIUType Value);
/// Find the highest bit set to 1 in a integer variable and return its value.
///
/// @see gtx_bit
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_DECL vecType<T, P> highestBitValue(vecType<T, P> const & value);
/// Return the power of two number which value is just higher the input value.
///
/// @see gtx_bit
template <typename genIUType>
GLM_FUNC_DECL genIUType powerOfTwoAbove(genIUType Value);
/// Return the power of two number which value is just higher the input value.
///
/// @see gtx_bit
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_DECL vecType<T, P> powerOfTwoAbove(vecType<T, P> const & value);
/// Return the power of two number which value is just lower the input value.
///
/// @see gtx_bit
template <typename genIUType>
GLM_FUNC_DECL genIUType powerOfTwoBelow(genIUType Value);
/// Return the power of two number which value is just lower the input value.
///
/// @see gtx_bit
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_DECL vecType<T, P> powerOfTwoBelow(vecType<T, P> const & value);
/// Return the power of two number which value is the closet to the input value.
///
/// @see gtx_bit
template <typename genIUType>
GLM_FUNC_DECL genIUType powerOfTwoNearest(genIUType Value);
/// Return the power of two number which value is the closet to the input value.
///
/// @see gtx_bit
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_DECL vecType<T, P> powerOfTwoNearest(vecType<T, P> const & value);
/// @}
} //namespace glm
#include "bit.inl"

103
glm/gtx/bit.inl Normal file
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@ -0,0 +1,103 @@
///////////////////////////////////////////////////////////////////////////////////
/// OpenGL Mathematics (glm.g-truc.net)
///
/// Copyright (c) 2005 - 2014 G-Truc Creation (www.g-truc.net)
/// 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.
///
/// @ref gtx_bit
/// @file glm/gtx/bit.inl
/// @date 2014-11-25 / 2014-11-25
/// @author Christophe Riccio
///////////////////////////////////////////////////////////////////////////////////
namespace glm
{
///////////////////
// highestBitValue
template <typename genIUType>
GLM_FUNC_QUALIFIER genIUType highestBitValue(genIUType Value)
{
genIUType tmp = Value;
genIUType result = genIUType(0);
while(tmp)
{
result = (tmp & (~tmp + 1)); // grab lowest bit
tmp &= ~result; // clear lowest bit
}
return result;
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> highestBitValue(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(highestBitValue, v);
}
///////////////////
// powerOfTwoAbove
template <typename genType>
GLM_FUNC_QUALIFIER genType powerOfTwoAbove(genType value)
{
return isPowerOfTwo(value) ? value : highestBitValue(value) << 1;
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> powerOfTwoAbove(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(powerOfTwoAbove, v);
}
///////////////////
// powerOfTwoBelow
template <typename genType>
GLM_FUNC_QUALIFIER genType powerOfTwoBelow(genType value)
{
return isPowerOfTwo(value) ? value : highestBitValue(value);
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> powerOfTwoBelow(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(powerOfTwoBelow, v);
}
/////////////////////
// powerOfTwoNearest
template <typename genType>
GLM_FUNC_QUALIFIER genType powerOfTwoNearest(genType value)
{
if(isPowerOfTwo(value))
return value;
genType const prev = highestBitValue(value);
genType const next = prev << 1;
return (next - value) < (value - prev) ? next : prev;
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> powerOfTwoNearest(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(powerOfTwoNearest, v);
}
}//namespace glm