diff --git a/src/camera.cpp b/src/camera.cpp
index 32dd85e..f87f660 100644
--- a/src/camera.cpp
+++ b/src/camera.cpp
@@ -34,6 +34,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "sound.h"
 #include "event.h"
 #include "util/numeric.h"
+#include "util/mathconstants.h"
 
 Camera::Camera(scene::ISceneManager* smgr, MapDrawControl& draw_control,
 		IGameDef *gamedef):
diff --git a/src/clientmap.cpp b/src/clientmap.cpp
index 6cf3db8..4d14cc1 100644
--- a/src/clientmap.cpp
+++ b/src/clientmap.cpp
@@ -29,6 +29,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "mapblock.h"
 #include "profiler.h"
 #include "settings.h"
+#include "util/mathconstants.h"
 
 #define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"
 
diff --git a/src/content_cao.cpp b/src/content_cao.cpp
index 5702a73..58ff130 100644
--- a/src/content_cao.cpp
+++ b/src/content_cao.cpp
@@ -38,6 +38,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "localplayer.h"
 #include "util/numeric.h" // For IntervalLimiter
 #include "util/serialize.h"
+#include "util/mathconstants.h"
 
 class Settings;
 struct ToolCapabilities;
diff --git a/src/server.cpp b/src/server.cpp
index b125bff..80df9fc 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -53,6 +53,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "hex.h"
 #include "util/string.h"
 #include "util/pointedthing.h"
+#include "util/mathconstants.h"
 
 #define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"
 
diff --git a/src/util/mathconstants.h b/src/util/mathconstants.h
new file mode 100644
index 0000000..1b478aa
--- /dev/null
+++ b/src/util/mathconstants.h
@@ -0,0 +1,7 @@
+#include <math.h>
+
+// MSVC doesn't seem to define this
+#ifndef M_PI
+	#define M_PI 3.1415926535
+#endif
+