From c7849901cf0eddacf0c9aa2997e33a00f3b0d9bc Mon Sep 17 00:00:00 2001
From: Lorenzo Cogotti <lcg@doublefourteen.io>
Date: Thu, 15 Sep 2022 09:18:25 +0200
Subject: [PATCH] [vec] Add cross product between vectors.

---
 vec.lua | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/vec.lua b/vec.lua
index 50857ca..622840e 100644
--- a/vec.lua
+++ b/vec.lua
@@ -25,6 +25,13 @@ function vec.dot3(x1,y1,z1, x2,y2,z2)
     return x1*x2 + y1*y2 + z1*z2
 end
 
+--- Vector cross product.
+function vec.cross(x1,y1,z1, x2,y2,z2)
+    return y1*z2 - z1*y2,
+           z1*x2 - x1*z2,
+           x1*y2 - y1*x2
+end
+
 --- Vector squared length.
 function vec.sqrlen(x,y)
     return x*x + y*y  -- vec.dot(x,y, x,y)