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Added equal and notEqual overload with max ULPs parameters for scalar numbers #121

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This commit is contained in:
Christophe Riccio 2018-09-04 02:14:48 +02:00
parent cf6504b65e
commit 72327cea4f
4 changed files with 118 additions and 6 deletions
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22
glm/ext/scalar_relational.hpp
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@ -37,6 +37,28 @@ namespace glm
template<typename genType>
GLM_FUNC_DECL GLM_CONSTEXPR bool notEqual(genType const& x, genType const& y, genType const& epsilon);
/// Returns the component-wise comparison between two scalars in term of ULPs.
/// True if this expression is satisfied.
///
/// @param x First operand.
/// @param y Second operand.
/// @param ULPs Maximum difference in ULPs between the two operators to consider them equal.
///
/// @tparam genType Floating-point or integer scalar types
template<typename genType>
GLM_FUNC_DECL GLM_CONSTEXPR bool equal(genType const& x, genType const& y, int ULPs);
/// Returns the component-wise comparison between two scalars in term of ULPs.
/// True if this expression is not satisfied.
///
/// @param x First operand.
/// @param y Second operand.
/// @param ULPs Maximum difference in ULPs between the two operators to consider them not equal.
///
/// @tparam genType Floating-point or integer scalar types
template<typename genType>
GLM_FUNC_DECL GLM_CONSTEXPR bool notEqual(genType const& x, genType const& y, int ULPs);
/// @}
}//namespace glm

43
glm/ext/scalar_relational.inl
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@ -1,7 +1,24 @@
#include "../common.hpp"
#include "../ext/scalar_int_sized.hpp"
#include "../ext/scalar_uint_sized.hpp"
namespace glm
namespace glm{
namespace detail
{
// https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
union float_t
{
GLM_CONSTEXPR float_t(float Num = 0.0f) : f(Num) {}
// Portable extraction of components.
GLM_CONSTEXPR bool negative() const { return i < 0; }
GLM_CONSTEXPR int32 mantissa() const { return i & ((1 << 23) - 1); }
GLM_CONSTEXPR int32 exponent() const { return (i >> 23) & 0xFF; }
int32 const i;
float const f;
};
}//namespace detail
template<typename genType>
GLM_FUNC_QUALIFIER GLM_CONSTEXPR bool equal(genType const& x, genType const& y, genType const& epsilon)
{
@ -13,4 +30,28 @@ namespace glm
{
return abs(x - y) > epsilon;
}
template<typename genType>
GLM_FUNC_QUALIFIER GLM_CONSTEXPR bool equal(genType const& x, genType const& y, int MaxULPs)
{
detail::float_t const a(x);
detail::float_t const b(y);
// Different signs means they do not match.
if(a.negative() != b.negative())
{
// Check for equality to make sure +0==-0
return a.mantissa() == b.mantissa() && a.exponent() == b.exponent();
}
// Find the difference in ULPs.
int const DiffULPs = abs(a.i - b.i);
return DiffULPs <= MaxULPs;
}
template<typename genType>
GLM_FUNC_QUALIFIER GLM_CONSTEXPR bool notEqual(genType const& x, genType const& y, int ULPs)
{
return !equal(x, y, ULPs);
}
}//namespace glm

3
readme.md
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@ -53,6 +53,9 @@ glm::mat4 camera(float Translate, glm::vec2 const& Rotate)
## Release notes
### [GLM 0.9.9.2](https://github.com/g-truc/glm/commits/master) - 2018-XX-XX
#### Features:
- Added equal and notEqual overload with max ULPs parameters for scalar numbers #121
#### Fixes:
- Fixed GLM_FORCE_CXX** section in the manual

56
test/ext/ext_scalar_relational.cpp
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@ -1,6 +1,7 @@
#include <glm/ext/scalar_relational.hpp>
#include <cmath>
int test_equal()
int test_equal_epsilon()
{
# if GLM_CONFIG_CONSTEXP == GLM_ENABLE
static_assert(glm::equal(1.01f, 1.02f, 0.1f), "GLM: Failed constexpr");
@ -15,7 +16,7 @@ int test_equal()
return Error;
}
int test_notEqual()
int test_notEqual_epsilon()
{
# if GLM_CONFIG_CONSTEXP == GLM_ENABLE
static_assert(glm::notEqual(1.01f, 1.02f, 0.001f), "GLM: Failed constexpr");
@ -30,12 +31,57 @@ int test_notEqual()
return Error;
}
#if GLM_LANG & GLM_LANG_CXX11_FLAG
int test_equal_ulps()
{
int Error = 0;
float const ULP1Plus = std::nextafter(1.0f, 2.0f);
Error += glm::equal(1.0f, ULP1Plus, 1) ? 0 : 1;
float const ULP2Plus = std::nextafter(ULP1Plus, 2.0f);
Error += !glm::equal(1.0f, ULP2Plus, 1) ? 0 : 1;
float const ULP1Minus = std::nextafter(1.0f, 0.0f);
Error += glm::equal(1.0f, ULP1Minus, 1) ? 0 : 1;
float const ULP2Minus = std::nextafter(ULP1Minus, 0.0f);
Error += !glm::equal(1.0f, ULP2Minus, 1) ? 0 : 1;
return Error;
}
int test_notEqual_ulps()
{
int Error = 0;
float const ULP1Plus = std::nextafter(1.0f, 2.0f);
Error += !glm::notEqual(1.0f, ULP1Plus, 1) ? 0 : 1;
float const ULP2Plus = std::nextafter(ULP1Plus, 2.0f);
Error += glm::notEqual(1.0f, ULP2Plus, 1) ? 0 : 1;
float const ULP1Minus = std::nextafter(1.0f, 0.0f);
Error += !glm::notEqual(1.0f, ULP1Minus, 1) ? 0 : 1;
float const ULP2Minus = std::nextafter(ULP1Minus, 0.0f);
Error += glm::notEqual(1.0f, ULP2Minus, 1) ? 0 : 1;
return Error;
}
#endif
int main()
{
int Error = 0;
Error += test_equal();
Error += test_notEqual();
Error += test_equal_epsilon();
Error += test_notEqual_epsilon();
#if GLM_LANG & GLM_LANG_CXX11_FLAG
Error += test_equal_ulps();
Error += test_notEqual_ulps();
#endif
return Error;
}