From c1cb6cba782c4e2e8dabf7d22f97f2dadf53add6 Mon Sep 17 00:00:00 2001
From: BlackMATov <blackmat@mail.ru>
Date: Sun, 28 Feb 2021 12:50:05 +0700
Subject: [PATCH] fix approx<float> with epsilon

---
 headers/vmath.hpp/vmath_fun.hpp | 20 +++++++-------------
 untests/vmath_fun_tests.cpp     |  9 +++++++++
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/headers/vmath.hpp/vmath_fun.hpp b/headers/vmath.hpp/vmath_fun.hpp
index f155291..88b9b61 100644
--- a/headers/vmath.hpp/vmath_fun.hpp
+++ b/headers/vmath.hpp/vmath_fun.hpp
@@ -393,6 +393,12 @@ namespace vmath_hpp
         return !!x;
     }
 
+    template < typename T >
+    [[nodiscard]] std::enable_if_t<std::is_arithmetic_v<T>, bool>
+    constexpr approx(T x, T y, T epsilon) noexcept {
+        return abs(x - y) <= epsilon;
+    }
+
     template < typename T >
     [[nodiscard]] std::enable_if_t<std::is_arithmetic_v<T>, bool>
     constexpr approx(T x, T y) noexcept {
@@ -400,24 +406,12 @@ namespace vmath_hpp
             /// REFERENCE:
             /// http://www.realtimecollisiondetection.net/pubs/Tolerances
             const T epsilon = std::numeric_limits<T>::epsilon();
-            return abs(x - y) <= epsilon * max(max(T{1}, abs(x)), abs(y));
+            return approx(x, y, epsilon * max(T{1}, max(abs(x), abs(y))));
         } else {
             return x == y;
         }
     }
 
-    template < typename T >
-    [[nodiscard]] std::enable_if_t<std::is_arithmetic_v<T>, bool>
-    constexpr approx(T x, T y, T epsilon) noexcept {
-        if constexpr ( std::is_floating_point_v<T> ) {
-            /// REFERENCE:
-            /// http://www.realtimecollisiondetection.net/pubs/Tolerances
-            return abs(x - y) <= epsilon * max(max(T{1}, abs(x)), abs(y));
-        } else {
-            return abs(x - y) <= epsilon;
-        }
-    }
-
     template < typename T >
     [[nodiscard]] std::enable_if_t<std::is_arithmetic_v<T>, bool>
     constexpr less(T x, T y) noexcept {
diff --git a/untests/vmath_fun_tests.cpp b/untests/vmath_fun_tests.cpp
index 4bb37e9..609e966 100644
--- a/untests/vmath_fun_tests.cpp
+++ b/untests/vmath_fun_tests.cpp
@@ -151,6 +151,15 @@ TEST_CASE("vmath/fun") {
         STATIC_CHECK_FALSE(approx(0, 1));
         STATIC_CHECK_FALSE(approx(0, 1, 0));
         STATIC_CHECK(approx(0, 1, 1));
+        STATIC_CHECK_FALSE(approx(1, 3, 1));
+        STATIC_CHECK(approx(1, 3, 2));
+
+        STATIC_CHECK(approx(1.f, 1.f));
+        STATIC_CHECK_FALSE(approx(0.f, 1.f));
+        STATIC_CHECK_FALSE(approx(0.f, 1.f, 0.f));
+        STATIC_CHECK(approx(0.f, 1.f, 1.f));
+        STATIC_CHECK_FALSE(approx(1.f, 3.f, 1.f));
+        STATIC_CHECK(approx(1.f, 3.f, 2.f));
 
         STATIC_CHECK(approx(1.f, 1.f + std::numeric_limits<float>::epsilon() * 0.5f));
         STATIC_CHECK_FALSE(approx(1.f, 1.f + std::numeric_limits<float>::epsilon() * 1.5f));