From f9be2ace4ca871d7ad68c1a4dbdcff87511d838b Mon Sep 17 00:00:00 2001
From: Franklin Wei <me@fwei.tk>
Date: Thu, 30 May 2019 23:03:58 -0400
Subject: Add some useful stuff

---
 src/vec3.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'src/vec3.cpp')

diff --git a/src/vec3.cpp b/src/vec3.cpp
index bf0b021..c03bdd9 100644
--- a/src/vec3.cpp
+++ b/src/vec3.cpp
@@ -102,4 +102,19 @@ namespace fml{
     {
         return v * scale;
     }
+
+    vec3 vec3::rotateby(const quat &rotquat) const
+    {
+        return rotquat * (*this) * rotquat.conjugate();
+    }
+
+#define EPS 1e-5
+#define ISZERO(a) ((fabs((a)) < EPS))
+
+    vec3 vec3::any_unit_normal(const vec3 &v)
+    {
+        if(ISZERO(v[0]) && ISZERO(v[1]))
+            return vec3(1, 0, 0);
+        return vec3(-v[1], v[0], 0).normalize();
+    }
 }
-- 
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