From e395b21ce02b3459e1b98f3c1af54132917989fd Mon Sep 17 00:00:00 2001
From: Daniel Warner <contact@danrw.com>
Date: Sat, 9 Apr 2011 21:39:13 +0100
Subject: [PATCH] Added AcTan method to Globals for use in observer
 calculations

---
 Globals.cpp | 24 +++++++++++++++++++++---
 Globals.h   |  7 ++++---
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/Globals.cpp b/Globals.cpp
index a2e2179..fd798ec 100644
--- a/Globals.cpp
+++ b/Globals.cpp
@@ -6,7 +6,8 @@ Globals::Globals(void) {
 Globals::~Globals(void) {
 }
 
-double Globals::Fmod2p(const double& arg) {
+double Globals::Fmod2p(const double arg) {
+
     double modu = fmod(arg, TWOPI());
     if (modu < 0.0)
         modu += TWOPI();
@@ -14,10 +15,27 @@ double Globals::Fmod2p(const double& arg) {
     return modu;
 }
 
-double Globals::Deg2Rad(const double& deg) {
+double Globals::Deg2Rad(const double deg) {
+
     return deg * PI() / 180.0;
 }
 
-double Globals::Rad2Deg(const double& rad) {
+double Globals::Rad2Deg(const double rad) {
+
     return rad * 180.0 / PI();
 }
+
+double Globals::AcTan(const double sinx, const double cosx) {
+
+    if (cosx == 0.0) {
+        if (sinx > 0.0)
+            return PI() / 2.0;
+        else
+            return 3.0 * PI() / 2.0;
+    } else {
+        if (cosx > 0.0)
+            return atan(sinx / cosx);
+        else
+            return PI() + atan(sinx / cosx);
+    }
+}
\ No newline at end of file
diff --git a/Globals.h b/Globals.h
index 320d158..9910f25 100644
--- a/Globals.h
+++ b/Globals.h
@@ -65,9 +65,10 @@ public:
         return 2451545.0;
     }
 
-    static double Fmod2p(const double& arg);
-    static double Deg2Rad(const double& deg);
-    static double Rad2Deg(const double& rad);
+    static double Fmod2p(const double arg);
+    static double Deg2Rad(const double deg);
+    static double Rad2Deg(const double rad);
+    static double AcTan(const double sinx, const double cosx);
 };
 
 #endif