From d9936c40fd9be160a0b9eddebd469b2051ebca2b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Sat, 12 May 2018 16:02:31 +0200
Subject: [PATCH] Math: added Constants::piQuarter().

---
 doc/changelog.dox                      |  6 ++++++
 src/Magnum/Math/Constants.h            | 17 +++++++++++----
 src/Magnum/Math/Test/ConstantsTest.cpp | 30 +++++++++++++++-----------
 3 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/doc/changelog.dox b/doc/changelog.dox
index 06b366683..a4eb32ae2 100644
--- a/doc/changelog.dox
+++ b/doc/changelog.dox
@@ -38,6 +38,12 @@ See also:
 
 @section changelog-latest Changes since 2018.04
 
+@subsection changelog-latest-new New features
+
+@subsubsection changelog-lates-new-math Math library
+
+-   Added @ref Math::piQuarter()
+
 @subsection changelog-latest-changes Changes and improvements
 
 -   @ref Platform::GlfwApplication now behaves the same as
diff --git a/src/Magnum/Math/Constants.h b/src/Magnum/Math/Constants.h
index df2739363..ea13c8dd8 100644
--- a/src/Magnum/Math/Constants.h
+++ b/src/Magnum/Math/Constants.h
@@ -48,22 +48,29 @@ template<class T> struct Constants {
     /**
      * @brief Pi
      *
-     * @see @ref piHalf(), @ref tau(), @ref Deg, @ref Rad
+     * @see @ref piHalf(), @ref piQuarter(), @ref tau(), @ref Deg, @ref Rad
      */
     static constexpr T pi();
 
     /**
-     * @brief Half pi
+     * @brief Half of a pi
      *
-     * @see @ref pi(), @ref tau(), @ref Deg, @ref Rad
+     * @see @ref pi(), @ref piQuarter(), @ref tau(), @ref Deg, @ref Rad
      */
     static constexpr T piHalf();
 
+    /**
+     * @brief Quarter of a pi
+     *
+     * @see @ref pi(), @ref piHalf(), @ref tau(), @ref Deg, @ref Rad
+     */
+    static constexpr T piQuarter();
+
     /**
      * @brief Tau
      *
      * Or two pi. See the [Tau manifesto](https://www.tauday.com/tau-manifesto).
-     * @see @ref pi(), @ref piHalf(), @ref Deg, @ref Rad
+     * @see @ref pi(), @ref piHalf(), @ref piQuarter(), @ref Deg, @ref Rad
      */
     static constexpr T tau();
 
@@ -93,6 +100,7 @@ template<> struct Constants<Double> {
 
     static constexpr Double pi()        { return 3.141592653589793; }
     static constexpr Double piHalf()    { return 1.570796326794897; }
+    static constexpr Double piQuarter() { return 0.785398163397448; }
     static constexpr Double tau()       { return 6.283185307179586; }
     static constexpr Double e()         { return 2.718281828459045; }
     static constexpr Double sqrt2()     { return 1.414213562373095; }
@@ -106,6 +114,7 @@ template<> struct Constants<Float> {
 
     static constexpr Float pi()         { return 3.141592654f; }
     static constexpr Float piHalf()     { return 1.570796327f; }
+    static constexpr Float piQuarter()  { return 0.785398163f; }
     static constexpr Float tau()        { return 6.283185307f; }
     static constexpr Float e()          { return 2.718281828f; }
     static constexpr Float sqrt2()      { return 1.414213562f; }
diff --git a/src/Magnum/Math/Test/ConstantsTest.cpp b/src/Magnum/Math/Test/ConstantsTest.cpp
index b3cea52a6..b2205dbe9 100644
--- a/src/Magnum/Math/Test/ConstantsTest.cpp
+++ b/src/Magnum/Math/Test/ConstantsTest.cpp
@@ -48,19 +48,23 @@ ConstantsTest::ConstantsTest() {
 template<class T> void ConstantsTest::constants() {
     setTestCaseName(std::is_same<T, Double>::value ? "constants<Double>" : "constants<Float>");
 
-    constexpr T a = Constants<T>::sqrt2();
-    constexpr T b = Constants<T>::sqrt3();
-    CORRADE_COMPARE(Math::pow<2>(a), T(2));
-    CORRADE_COMPARE(Math::pow<2>(b), T(3));
-
-    constexpr T c = Constants<T>::pi();
-    constexpr T d = Constants<T>::piHalf();
-    constexpr T e = Constants<T>::tau();
-    CORRADE_COMPARE(T(0.5)*c, d);
-    CORRADE_COMPARE(T(2.0)*c, e);
-
-    constexpr T f = Constants<T>::e();
-    CORRADE_COMPARE(std::log(f), T(1));
+    {
+        constexpr T a = Constants<T>::sqrt2();
+        constexpr T b = Constants<T>::sqrt3();
+        CORRADE_COMPARE(Math::pow<2>(a), T(2));
+        CORRADE_COMPARE(Math::pow<2>(b), T(3));
+    } {
+        constexpr T a = Constants<T>::pi();
+        constexpr T b = Constants<T>::piHalf();
+        constexpr T c = Constants<T>::piQuarter();
+        constexpr T d = Constants<T>::tau();
+        CORRADE_COMPARE(T(0.50)*a, b);
+        CORRADE_COMPARE(T(0.25)*a, c);
+        CORRADE_COMPARE(T(2.00)*a, d);
+    } {
+        constexpr T e = Constants<T>::e();
+        CORRADE_COMPARE(std::log(e), T(1));
+    }
 }
 
 template<class T> void ConstantsTest::specials() {