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Aquaria/ExternalLibs/glm/gtx/ulp.inl
2015-07-12 22:07:27 +02:00

396 lines
11 KiB
C++

///////////////////////////////////////////////////////////////////////////////////////////////////
// OpenGL Mathematics Copyright (c) 2005 - 2011 G-Truc Creation (www.g-truc.net)
///////////////////////////////////////////////////////////////////////////////////////////////////
// Created : 2011-03-07
// Updated : 2011-04-26
// Licence : This source is under MIT License
// File : glm/gtx/ulp.inl
///////////////////////////////////////////////////////////////////////////////////////////////////
#include <cmath>
#include <cfloat>
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
typedef union
{
float value;
/* FIXME: Assumes 32 bit int. */
unsigned int word;
} ieee_float_shape_type;
typedef union
{
double value;
struct
{
glm::detail::int32 lsw;
glm::detail::int32 msw;
} parts;
} ieee_double_shape_type;
#define GLM_EXTRACT_WORDS(ix0,ix1,d) \
do { \
ieee_double_shape_type ew_u; \
ew_u.value = (d); \
(ix0) = ew_u.parts.msw; \
(ix1) = ew_u.parts.lsw; \
} while (0)
#define GLM_GET_FLOAT_WORD(i,d) \
do { \
ieee_float_shape_type gf_u; \
gf_u.value = (d); \
(i) = gf_u.word; \
} while (0)
#define GLM_SET_FLOAT_WORD(d,i) \
do { \
ieee_float_shape_type sf_u; \
sf_u.word = (i); \
(d) = sf_u.value; \
} while (0)
#define GLM_INSERT_WORDS(d,ix0,ix1) \
do { \
ieee_double_shape_type iw_u; \
iw_u.parts.msw = (ix0); \
iw_u.parts.lsw = (ix1); \
(d) = iw_u.value; \
} while (0)
namespace glm{
namespace detail
{
GLM_FUNC_QUALIFIER float nextafterf(float x, float y)
{
volatile float t;
glm::detail::int32 hx, hy, ix, iy;
GLM_GET_FLOAT_WORD(hx,x);
GLM_GET_FLOAT_WORD(hy,y);
ix = hx&0x7fffffff; // |x|
iy = hy&0x7fffffff; // |y|
if((ix>0x7f800000) || // x is nan
(iy>0x7f800000)) // y is nan
return x+y;
if(x==y) return y; // x=y, return y
if(ix==0) { // x == 0
GLM_SET_FLOAT_WORD(x,(hy&0x80000000)|1);// return +-minsubnormal
t = x*x;
if(t==x) return t; else return x; // raise underflow flag
}
if(hx>=0) { // x > 0
if(hx>hy) { // x > y, x -= ulp
hx -= 1;
} else { // x < y, x += ulp
hx += 1;
}
} else { // x < 0
if(hy>=0||hx>hy){ // x < y, x -= ulp
hx -= 1;
} else { // x > y, x += ulp
hx += 1;
}
}
hy = hx&0x7f800000;
if(hy>=0x7f800000) return x+x; // overflow
if(hy<0x00800000) { // underflow
t = x*x;
if(t!=x) { // raise underflow flag
GLM_SET_FLOAT_WORD(y,hx);
return y;
}
}
GLM_SET_FLOAT_WORD(x,hx);
return x;
}
GLM_FUNC_QUALIFIER double nextafter(double x, double y)
{
volatile double t;
glm::detail::int32 hx, hy, ix, iy;
glm::detail::uint32 lx, ly;
GLM_EXTRACT_WORDS(hx, lx, x);
GLM_EXTRACT_WORDS(hy, ly, y);
ix = hx & 0x7fffffff; // |x|
iy = hy & 0x7fffffff; // |y|
if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || // x is nan
((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) // y is nan
return x+y;
if(x==y) return y; // x=y, return y
if((ix|lx)==0) { // x == 0
GLM_INSERT_WORDS(x, hy & 0x80000000, 1); // return +-minsubnormal
t = x*x;
if(t==x) return t; else return x; // raise underflow flag
}
if(hx>=0) { // x > 0
if(hx>hy||((hx==hy)&&(lx>ly))) { // x > y, x -= ulp
if(lx==0) hx -= 1;
lx -= 1;
} else { // x < y, x += ulp
lx += 1;
if(lx==0) hx += 1;
}
} else { // x < 0
if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){// x < y, x -= ulp
if(lx==0) hx -= 1;
lx -= 1;
} else { // x > y, x += ulp
lx += 1;
if(lx==0) hx += 1;
}
}
hy = hx&0x7ff00000;
if(hy>=0x7ff00000) return x+x; // overflow
if(hy<0x00100000) { // underflow
t = x*x;
if(t!=x) { // raise underflow flag
GLM_INSERT_WORDS(y,hx,lx);
return y;
}
}
GLM_INSERT_WORDS(x,hx,lx);
return x;
}
}//namespace detail
}//namespace glm
#if(GLM_COMPILER & GLM_COMPILER_VC)
# define GLM_NEXT_AFTER_FLT(x, toward) glm::detail::nextafterf((x), (toward))
# define GLM_NEXT_AFTER_DBL(x, toward) _nextafter((x), (toward))
#else
# define GLM_NEXT_AFTER_FLT(x, toward) nextafterf((x), (toward))
# define GLM_NEXT_AFTER_DBL(x, toward) nextafter((x), (toward))
#endif
namespace glm{
namespace gtx{
namespace ulp
{
GLM_FUNC_QUALIFIER float next_float(float const & x)
{
return GLM_NEXT_AFTER_FLT(x, std::numeric_limits<float>::max());
}
GLM_FUNC_QUALIFIER double next_float(double const & x)
{
return GLM_NEXT_AFTER_DBL(x, std::numeric_limits<double>::max());
}
template<typename T, template<typename> class vecType>
GLM_FUNC_QUALIFIER vecType<T> next_float(vecType<T> const & x)
{
vecType<T> Result;
for(std::size_t i = 0; i < Result.length(); ++i)
Result[i] = next_float(x[i]);
return Result;
}
GLM_FUNC_QUALIFIER float prev_float(float const & x)
{
return GLM_NEXT_AFTER_FLT(x, std::numeric_limits<float>::min());
}
GLM_FUNC_QUALIFIER double prev_float(double const & x)
{
return GLM_NEXT_AFTER_DBL(x, std::numeric_limits<double>::min());
}
template<typename T, template<typename> class vecType>
GLM_FUNC_QUALIFIER vecType<T> prev_float(vecType<T> const & x)
{
vecType<T> Result;
for(std::size_t i = 0; i < Result.length(); ++i)
Result[i] = prev_float(x[i]);
return Result;
}
template <typename T>
GLM_FUNC_QUALIFIER T next_float(T const & x, uint const & ulps)
{
T temp = x;
for(std::size_t i = 0; i < ulps; ++i)
temp = next_float(temp);
return temp;
}
template<typename T, template<typename> class vecType>
GLM_FUNC_QUALIFIER vecType<T> next_float(vecType<T> const & x, vecType<uint> const & ulps)
{
vecType<T> Result;
for(std::size_t i = 0; i < Result.length(); ++i)
Result[i] = next_float(x[i], ulps[i]);
return Result;
}
template <typename T>
GLM_FUNC_QUALIFIER T prev_float(T const & x, uint const & ulps)
{
T temp = x;
for(std::size_t i = 0; i < ulps; ++i)
temp = prev_float(temp);
return temp;
}
template<typename T, template<typename> class vecType>
GLM_FUNC_QUALIFIER vecType<T> prev_float(vecType<T> const & x, vecType<uint> const & ulps)
{
vecType<T> Result;
for(std::size_t i = 0; i < Result.length(); ++i)
Result[i] = prev_float(x[i], ulps[i]);
return Result;
}
template <typename T>
GLM_FUNC_QUALIFIER uint float_distance(T const & x, T const & y)
{
uint ulp = 0;
if(x < y)
{
T temp = x;
while(temp != y && ulp < std::numeric_limits<std::size_t>::max())
{
++ulp;
temp = next_float(temp);
}
}
else if(y < x)
{
T temp = y;
while(temp != x && ulp < std::numeric_limits<std::size_t>::max())
{
++ulp;
temp = next_float(temp);
}
}
else // ==
{
}
return ulp;
}
template<typename T, template<typename> class vecType>
GLM_FUNC_QUALIFIER vecType<uint> float_distance(vecType<T> const & x, vecType<T> const & y)
{
vecType<uint> Result;
for(std::size_t i = 0; i < Result.length(); ++i)
Result[i] = float_distance(x[i], y[i]);
return Result;
}
/*
inline std::size_t ulp
(
detail::thalf const & a,
detail::thalf const & b
)
{
std::size_t Count = 0;
float TempA(a);
float TempB(b);
//while((TempA = _nextafterf(TempA, TempB)) != TempB)
++Count;
return Count;
}
inline std::size_t ulp
(
float const & a,
float const & b
)
{
std::size_t Count = 0;
float Temp = a;
//while((Temp = _nextafterf(Temp, b)) != b)
{
std::cout << Temp << " " << b << std::endl;
++Count;
}
return Count;
}
inline std::size_t ulp
(
double const & a,
double const & b
)
{
std::size_t Count = 0;
double Temp = a;
//while((Temp = _nextafter(Temp, b)) != b)
{
std::cout << Temp << " " << b << std::endl;
++Count;
}
return Count;
}
template <typename T>
inline std::size_t ulp
(
detail::tvec2<T> const & a,
detail::tvec2<T> const & b
)
{
std::size_t ulps[] =
{
ulp(a[0], b[0]),
ulp(a[1], b[1])
};
return glm::max(ulps[0], ulps[1]);
}
template <typename T>
inline std::size_t ulp
(
detail::tvec3<T> const & a,
detail::tvec3<T> const & b
)
{
std::size_t ulps[] =
{
ulp(a[0], b[0]),
ulp(a[1], b[1]),
ulp(a[2], b[2])
};
return glm::max(glm::max(ulps[0], ulps[1]), ulps[2]);
}
template <typename T>
inline std::size_t ulp
(
detail::tvec4<T> const & a,
detail::tvec4<T> const & b
)
{
std::size_t ulps[] =
{
ulp(a[0], b[0]),
ulp(a[1], b[1]),
ulp(a[2], b[2]),
ulp(a[3], b[3])
};
return glm::max(glm::max(ulps[0], ulps[1]), glm::max(ulps[2], ulps[3]));
}
*/
}//namespace ulp
}//namespace gtx
}//namespace glm