From 504961a0a2af78ccb6d0011ebb022bcd83b3b72b Mon Sep 17 00:00:00 2001
From: paramat <mat.gregory@virginmedia.com>
Date: Sun, 8 May 2016 22:26:18 +0100
Subject: [PATCH] cherry-pick from github.com/minetest/minetest_game> Tnt:
 Avoid divide-by-zero errors in calc_velocity()

---
 mods/tnt/init.lua | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mods/tnt/init.lua b/mods/tnt/init.lua
index 1e5d5a50..18bd9263 100644
--- a/mods/tnt/init.lua
+++ b/mods/tnt/init.lua
@@ -104,6 +104,11 @@ end
 
 
 local function calc_velocity(pos1, pos2, old_vel, power)
+	-- Avoid errors caused by a vector of zero length
+	if vector.equals(pos1, pos2) then
+		return old_vel
+	end
+
 	local vel = vector.direction(pos1, pos2)
 	vel = vector.normalize(vel)
 	vel = vector.multiply(vel, power)