Add node attachment locking.

Uses an entity to prevent player from moving away. Only `space` will
allow the player to move again. The player is put on top of the node
when detaching. While attached, the player can't move and the player
model can not rotate.

README.md

@@ -24,7 +24,7 @@ Stops any emote for the named player.
 
 Lists known emotestring values.
 
-`emote.attach_to_node(player, pos)`
+`emote.attach_to_node(player, pos, locked)`
 
 Attach the player to the node at pos. The attachment will be made using the
 parameters provided in the `emote` table in the nodedef:
@@ -37,6 +37,10 @@ nodedef.emote = {
 }
 ```
 
+if `locked` is `true`, then the player is fixed to the node and can only
+move until he presses `jump`. While sitting the player can look around but
+his character does not turn.
+
 The player offset vector will be rotated to account for the node facedir.
 
 ## Commands

init.lua

@@ -23,6 +23,7 @@ local emotes = {
 }
 
 local emoting = {}
+local attached = {}
 
 -- helper functions
 local function facedir_to_look_horizontal(dir)
@@ -48,6 +49,45 @@ local function vector_rotate_xz(vec, angle)
 	}
 end
 
+-- entity for locked emotes (attached to nodes, etc)
+local attacher = {
+	description = "Attachment entity for emotes",
+	physical = false,
+	visual = "upright_sprite",
+	visual_size = {x = 1/16, y = 1/16},
+	spritediv = {x = 1/16, y = 1/16},
+	collisionbox = {-1/16, -1/16, -1/16, 1/16, 1/16, 1/16},
+	textures = {"emote_blank.png"},
+	init = function(self, player)
+		self.player = player
+	end,
+}
+
+function attacher:on_step(dtime)
+	if not self.player then
+		self.object:remove()
+		return
+	end
+
+	local ctrl = self.player:get_player_control()
+	if ctrl.jump then
+		self:detach()
+		return
+	end
+end
+
+function attacher:detach()
+	attached[self.player] = nil
+	self.player:set_detach()
+	self.player:set_animation(unpack(emotes["stand"]))
+	self.object:remove()
+	default.player_attached[self.player:get_player_name()] = nil
+end
+
+minetest.register_entity("emote:attacher", attacher)
+
+-- API functions
+
 function emote.start(player, emotestring)
 	emote.stop(player)
 	if emotes[emotestring] then
@@ -79,12 +119,16 @@ function emote.list()
 	return r
 end
 
-function emote.attach_to_node(player, pos)
+function emote.attach_to_node(player, pos, locked)
 	local node = minetest.get_node(pos)
 	if node.name == "ignore" then
 		return false
 	end
 
+	if attached[player] then
+		return
+	end
+
 	local def = minetest.registered_nodes[node.name].emote or {}
 
 	local emotedef = {
@@ -94,11 +138,28 @@ function emote.attach_to_node(player, pos)
 		emotestring = def.emotestring or "sit",
 	}
 
+	if locked then
+		player:set_animation(unpack(emotes[emotedef.emotestring]))
+		local offset = vector_rotate_xz(emotedef.player_offset,facedir_to_look_horizontal(node.param2))
+		local object = minetest.add_entity(vector.add(pos, offset), "emote:attacher")
+		object:get_luaentity():init(player)
+		local rotation = facedir_to_look_horizontal(node.param2) + emotedef.look_horizontal_offset
+		object:setyaw(rotation)
+		player:set_attach(object, "", emotedef.eye_offset, minetest.facedir_to_dir(node.param2))
+		player:set_look_horizontal(rotation)
+		-- this is highly unreliable!
+		minetest.after(0, function()
+			player:set_animation(unpack(emotes[emotedef.emotestring]))
+		end)
+		attached[player] = object
+		default.player_attached[player:get_player_name()] = true
+	else
 		player:setpos(vector.add(pos, vector_rotate_xz(emotedef.player_offset, facedir_to_look_horizontal(node.param2))))
 		player:set_eye_offset(emotedef.eye_offset, {x = 0, y = 0, z = 0})
 		player:set_look_horizontal(facedir_to_look_horizontal(node.param2) + emotedef.look_horizontal_offset)
 		player:set_animation(unpack(emotes[emotedef.emotestring]))
 		player:set_physics_override(0, 0, 0)
+	end
 end
 
 function emote.attach_to_entity(player, emotestring, obj)
@@ -106,6 +167,9 @@ function emote.attach_to_entity(player, emotestring, obj)
 end
 
 function emote.detach(player)
+	if attached[player] then
+		attached[player]:detach()
+	end
 	-- check if attached?
 	player:set_eye_offset(vector.new(), vector.new())
 	player:set_physics_override(1, 1, 1)