1 files changed, 22 insertions, 0 deletions
diff --git a/include/mbgl/util/interpolate.hpp b/include/mbgl/util/interpolate.hpp
index aff730a0a2..1de626f701 100644
--- a/include/mbgl/util/interpolate.hpp
+++ b/include/mbgl/util/interpolate.hpp
@@ -3,6 +3,7 @@
 #include <mbgl/util/color.hpp>
 #include <mbgl/util/range.hpp>
 #include <mbgl/style/position.hpp>
+#include <mbgl/style/rotation.hpp>
 #include <mbgl/style/expression/value.hpp>
 
 #include <array>
@@ -102,6 +103,27 @@ public:
     }
 };
 
+template <>
+struct Interpolator<style::Rotation> {
+public:
+    style::Rotation operator()(const style::Rotation& a, const style::Rotation& b, const double t) {
+        assert(a.period() == b.period());
+        auto period = a.period();
+        auto aAngle = std::fmod(a.getAngle(), period);
+        auto bAngle = std::fmod(b.getAngle(), period);
+
+        if (aAngle - bAngle > period * 0.5) {
+            return {std::fmod(aAngle * (1.0 - t) + (bAngle + period) * t, period)};
+        }
+
+        if (aAngle - bAngle < period * -0.5) {
+            return {std::fmod((aAngle + period) * (1.0 - t) + bAngle * t, period)};
+        }
+
+        return {aAngle * (1.0 - t) + bAngle * t};
+    }
+};
+
 struct Uninterpolated {
     template <class T>
     T operator()(const T& a, const T&, const double) const {