/glm/gtx/ulp.inl
https://bitbucket.org/ggerganov/test_opengl · C++ Header · 299 lines · 248 code · 32 blank · 19 comment · 56 complexity · cf25eb10af997fd49dae0cc839970cbf MD5 · raw file
- ///////////////////////////////////////////////////////////////////////////////////////////////////
- // OpenGL Mathematics Copyright (c) 2005 - 2012 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.
- * ====================================================
- */
-
- #pragma warning(push)
- #pragma warning(disable : 4127)
-
- 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
-
- #pragma warning(pop)
-
- #if(GLM_COMPILER & GLM_COMPILER_VC || GLM_COMPILER & GLM_COMPILER_INTEL)
- # 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
- {
- 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;
- }
- }//namespace glm