From 24b1a90d0a04f3a242ed6c4f2aeaec57bb38e614 Mon Sep 17 00:00:00 2001
From: Lars Mueller <appgurulars@gmx.de>
Date: Sat, 6 Feb 2021 12:01:47 +0100
Subject: [PATCH] Add quaternion.from_euler_rotation

---
 quaternion.lua | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/quaternion.lua b/quaternion.lua
index 25ef830..03529f6 100644
--- a/quaternion.lua
+++ b/quaternion.lua
@@ -1,3 +1,17 @@
+-- TODO OOP, extend vector
+
+function from_euler_rotation(rotation)
+	rotation = vector.divide(rotation, 2)
+	local cos = vector.apply(rotation, math.cos)
+	local sin = vector.apply(rotation, math.sin)
+	return {
+    	sin.z * cos.x * cos.y - cos.z * sin.x * sin.y,
+    	cos.z * sin.x * cos.y + sin.z * cos.x * sin.y,
+		cos.z * cos.x * sin.y - sin.z * sin.x * cos.y,
+		cos.z * cos.x * cos.y + sin.z * sin.x * sin.y
+	}
+end
+
 function multiply(self, other)
 	return {
 		other[1] * self[1] - other[2] * self[2] - other[3] * self[3] - other[4] * self[4],
@@ -60,7 +74,7 @@ function slerp(self, other, ratio)
 	return modlib.vector.add(modlib.vector.multiply_scalar(self, s_0), modlib.vector.multiply_scalar(other, s_1))
 end
 
---> {x, y, z} euler rotation in degrees
+--> {x = pitch, y = yaw, z = roll} euler rotation in degrees
 function to_euler_rotation(self)
     local rotation = {}