From 263560f48cc4ae578380b21d54cad7995b55f2f2 Mon Sep 17 00:00:00 2001
From: Lars Mueller <appgurulars@gmx.de>
Date: Sat, 3 Jul 2021 17:29:35 +0200
Subject: [PATCH] Add vector.rotate3

---
 vector.lua | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/vector.lua b/vector.lua
index 1c903ce..a25312d 100644
--- a/vector.lua
+++ b/vector.lua
@@ -190,6 +190,14 @@ function angle(v, w)
 	return math.acos(dot(v, w) / length(v) / length(w))
 end
 
+-- Uses Rodrigues' rotation formula
+function rotate3(v, axis, angle)
+	local cos = math.cos(angle)
+	return multiply_scalar(v, cos)
+		+ multiply_scalar(cross3(axis, v), math.sin(angle))
+		+ multiply_scalar(axis, dot(axis, v) * (1 - cos))
+end
+
 function box_box_collision(diff, box, other_box)
 	for index, diff in pairs(diff) do
 		if box[index] + diff > other_box[index + 3] or other_box[index] > box[index + 3] + diff then