diff --git a/LICENSE.txt b/LICENSE.txt
index 62bb375..4ef25aa 100644
--- a/LICENSE.txt
+++ b/LICENSE.txt
@@ -1,5 +1,17 @@
-Licence of vignette textures
+License of source code
+----------------------
+
+The MIT License (MIT)
+Copyright 2018 kestral246
+
+https://opensource.org/licenses/MIT
+
+
+Licence of media (textures)
+---------------------------
 
 Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)
+Copyright 2018 kestral246
+
 http://creativecommons.org/licenses/by-sa/3.0/
 
diff --git a/init.lua b/init.lua
index 666e6ee..fefcab6 100644
--- a/init.lua
+++ b/init.lua
@@ -1,10 +1,44 @@
+-- vignette
+-- Adds a vignette filter to player's screen
+-- Based on concept by TriBlade9
+-- By David_G (kestral246@gmail.com)
+-- Includes chat command "/vignette", which toggles effect off or on
+
+local vignette = {}
+
 minetest.register_on_joinplayer(function(player)
-    player:hud_add({
-        hud_elem_type = "image",
-        text = "vignette.png",
-        position = {x=0, y=0},
-        scale = {x=-100, y=-100},
-        alignment = {x=1, y=1},
-        offset = {x=0, y=0}
-    })
+	local pname = player:get_player_name()
+	vignette[pname] = {
+		id = player:hud_add({
+			hud_elem_type = "image",
+			text = "vignette.png",
+			position = {x=0, y=0},
+			scale = {x=-100, y=-100},
+			alignment = {x=1, y=1},
+			offset = {x=0, y=0}
+		}),
+		enable = true }
+end)
+
+minetest.register_chatcommand("vignette", {
+	params = "",
+	description = "Toggle display of vignette mask.",
+	privs = {},
+	func = function(name, param)
+		local player = minetest.get_player_by_name(name)
+		if vignette[name].enable == true then
+			player:hud_change(vignette[name].id, "text", "blank.png")
+			vignette[name].enable = false
+		else
+			player:hud_change(vignette[name].id, "text", "vignette.png")
+			vignette[name].enable = true
+		end
+	end,
+})
+
+minetest.register_on_leaveplayer(function(player)
+	local pname = player:get_player_name()
+	if vignette[pname] then
+		vignette[pname] = nil
+	end
 end)
diff --git a/textures/blank.png b/textures/blank.png
new file mode 100644
index 0000000..cf9be3e
Binary files /dev/null and b/textures/blank.png differ