From 0a2d163bb15f70d96a2efc5925f59d9a881d0163 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Wed, 21 Jan 2015 23:39:23 +1100
Subject: [PATCH] maths: seperate float and double PI

---
 lerp.cpp             |  2 +-
 maths.hpp            | 17 +++++++++++++----
 test/maths/maths.cpp | 10 +++++++---
 3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/lerp.cpp b/lerp.cpp
index f930e5b8..e6ccf019 100644
--- a/lerp.cpp
+++ b/lerp.cpp
@@ -45,7 +45,7 @@ lerp::linear (double a, double b, double weight) {
 double
 lerp::cosine (double a, double b, double weight) {
     CHECK (weight >= 0.0 && weight <= 1.0);
-    double t  = (1.0 - cos (weight * PI)) * 0.5;
+    double t  = (1.0 - cos (weight * PI_d)) * 0.5;
 
     return a * (1.0 - t) + b * t;
 }
diff --git a/maths.hpp b/maths.hpp
index 2823d2aa..33fb4296 100644
--- a/maths.hpp
+++ b/maths.hpp
@@ -164,24 +164,33 @@ exactly_zero (T a)
 
 
 //-----------------------------------------------------------------------------
-constexpr double PI = 3.141592653589793238462643;
+// angles, trig
+constexpr double PI_d = 3.141592653589793238462643;
+constexpr float  PI_f = 3.141592653589793238462643f;
 
 //-----------------------------------------------------------------------------
 constexpr double
 to_degrees (double radians) {
-    return radians * 180 / PI;
+    return radians * 180 / PI_d;
 }
 
+
+constexpr float
+to_degrees (float radians) {
+    return radians * 180 / PI_f;
+}
+
+
 //-----------------------------------------------------------------------------
 constexpr float
 to_radians (float degrees) {
-    return degrees / 180 * static_cast<float> (PI);
+    return degrees / 180 * static_cast<float> (PI_f);
 }
 
 
 constexpr double
 to_radians (double degrees) {
-    return degrees / 180 * PI;
+    return degrees / 180 * PI_d;
 }
 
 
diff --git a/test/maths/maths.cpp b/test/maths/maths.cpp
index 69eb3c67..eddf45e0 100644
--- a/test/maths/maths.cpp
+++ b/test/maths/maths.cpp
@@ -10,6 +10,9 @@ using std::numeric_limits;
 
 int
 main (int, char **) {
+    std::cerr.precision (15);
+    std::cout.precision (15);
+
     CHECK_HARD (!almost_equal (-2.0, 0.0));
     CHECK_HARD (!almost_equal (-2.f, 0.f));
     CHECK_HARD ( almost_equal ( 0.0, 0.0));
@@ -39,9 +42,10 @@ main (int, char **) {
     CHECK_EQ (sign ( numeric_limits<double>::infinity ()),  1);
     CHECK_EQ (sign (-numeric_limits<double>::infinity ()), -1);
 
-    CHECK_EQ (to_degrees (PI),  180);
-    CHECK_EQ (to_radians (180.f),  PI);
-    CHECK_EQ (to_radians (180.0),  PI);
+    CHECK_EQ (to_degrees (PI_d),  180.0);
+    CHECK_EQ (to_degrees (PI_f),  180.f);
+    CHECK_EQ (to_radians (180.f),  PI_f);
+    CHECK_EQ (to_radians (180.0),  PI_d);
 
     CHECK_EQ (log2 (8u), 3);
     CHECK_EQ (log2 (1u), 0);