From 0b67ecf0735ffb2467b6d25d4f85950bab79504b Mon Sep 17 00:00:00 2001
From: Phillip Stephens <antidote.crk@gmail.com>
Date: Sun, 30 Jul 2017 00:43:44 -0700
Subject: [PATCH] Add `MakeRotationsBasedOnY` to CTransform

---
 include/zeus/CTransform.hpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/zeus/CTransform.hpp b/include/zeus/CTransform.hpp
index 3edcecf..3bf23bd 100644
--- a/include/zeus/CTransform.hpp
+++ b/include/zeus/CTransform.hpp
@@ -5,6 +5,7 @@
 #include "zeus/CMatrix3f.hpp"
 #include "zeus/CMatrix4f.hpp"
 #include "zeus/CVector3f.hpp"
+#include "zeus/CUnitVector.hpp"
 #include <stdint.h>
 #include <stdio.h>
 
@@ -246,6 +247,20 @@ public:
                0.f, 0.f, 0.f, 1.f);
     }
 
+    static zeus::CTransform MakeRotationsBasedOnY(const CUnitVector3f& uVec)
+    {
+        uint32_t i;
+        if (uVec.y < uVec.x || uVec.z < uVec.y || uVec.z < uVec.x)
+            i = 2;
+        else
+            i = 1;
+
+        CVector3f v = CVector3f::skZero;
+        v[i] = 1.f;
+        CUnitVector3f newUVec(uVec.cross(v));
+        return {newUVec, uVec, uVec.cross(newUVec), CVector3f::skZero};
+    }
+
     CMatrix3f basis;
     CVector3f origin;
 };