From 46a6173bd744c7d2a65fc6533e0d6a37a93e7e5b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Minh=20Nguy=E1=BB=85n?= <mxn@1ec5.org>
Date: Thu, 2 Jul 2015 13:03:32 -0700
Subject: [PATCH] [wrap)

If (wrap] is desired, it is the responsibility of the caller to handle the case in which min is returned.
---
 include/mbgl/util/math.hpp | 4 +++-
 src/mbgl/map/transform.cpp | 1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/mbgl/util/math.hpp b/include/mbgl/util/math.hpp
index 5fcf3dce8..37b1dd343 100644
--- a/include/mbgl/util/math.hpp
+++ b/include/mbgl/util/math.hpp
@@ -112,10 +112,12 @@ T clamp(T value, T min, T max) {
     return value < min ? min : (value > max ? max : value);
 }
 
+// Constrains n to the given range (including min, excluding max) via modular
+// arithmetic.
 template <typename T>
 T wrap(T value, T min, T max) {
     T d = max - min;
-    return value == max ? value : std::fmod((std::fmod((value - min), d) + d), d) + min;
+    return std::fmod((std::fmod((value - min), d) + d), d) + min;
 }
 
 template <typename T>
diff --git a/src/mbgl/map/transform.cpp b/src/mbgl/map/transform.cpp
index 7ea437606..14b3611a1 100644
--- a/src/mbgl/map/transform.cpp
+++ b/src/mbgl/map/transform.cpp
@@ -15,6 +15,7 @@ using namespace mbgl;
 static double _normalizeAngle(double angle, double anchorAngle)
 {
     angle = util::wrap(angle, -M_PI, M_PI);
+    if (angle == -M_PI) angle = M_PI;
     double diff = std::abs(angle - anchorAngle);
     if (std::abs(angle - util::M2PI - anchorAngle) < diff) {
         angle -= util::M2PI;