Added spectate control

modules/control/spectate.lua

@@ -0,0 +1,146 @@
+
+local Event = require 'utils.event' --- @dep utils.event
+local Global = require 'utils.global' --- @dep utils.global
+local Gui = require 'expcore.gui' --- @dep expcore.gui
+
+----- Locals -----
+local follow_label -- Gui constructor
+local following = {}
+local spectating = {}
+local Public = {}
+
+----- Global data -----
+Global.register({
+    following = following,
+    spectating = spectating
+}, function(tbl)
+    following = tbl.following
+    spectating = tbl.spectating
+end)
+
+----- Public Functions -----
+
+--- Puts a player into spectator while maintaining an association to their character
+-- @tparam LuaPlayer player The player that will be placed into spectator
+-- @treturn boolean Returns false if the player was already in spectator
+function Public.start_spectate(player)
+    assert(player and player.valid, 'Invalid player given to follower')
+    if spectating[player.index] or not player.character then return false end
+    local character = player.character
+    player.set_controller{ type = defines.controllers.spectator }
+    player.associate_character(character)
+    spectating[player.index] = character
+    return true
+end
+
+--- Return a player from spectator back to their character, if the character was killed then respawn the character
+-- @tparam LuaPlayer player The player that will leave spectator
+function Public.stop_spectate(player)
+    assert(player and player.valid, 'Invalid player given to follower')
+    local character = spectating[player.index]
+    spectating[player.index] = nil
+    if character and character.valid then
+        player.teleport(character.position, character.surface)
+        player.set_controller{ type = defines.controllers.character, character = character }
+    else
+        player.ticks_to_respawn = 300
+    end
+end
+
+--- Puts a player into spectator and follows an entity as it moves
+-- @tparam LuaPlayer player The player that will follow the entity
+-- @tparam ?LuaPlayer|LuaEntity entity The player or entity that will be followed
+function Public.start_follow(player, entity)
+    assert(player and player.valid, 'Invalid player given to follower')
+    assert(entity and entity.valid, 'Invalid entity given to follower')
+    local spectate = Public.start_spectate(player)
+
+    player.close_map()
+    follow_label(player.gui.screen, entity)
+    player.teleport(entity.position, entity.surface)
+    following[player.index] = { player, entity, entity.position, spectate }
+end
+
+--- Stops a player from following their current entity, can also return a player from spectate
+-- @tparam LuaPlayer player The player that you want to stop following their entity
+function Public.stop_follow(player)
+    assert(player and player.valid, 'Invalid player given to follower')
+    if following[player.index] and following[player.index][4] then Public.stop_spectate(player) end
+
+    Gui.destroy_if_valid(player.gui.screen[follow_label.name])
+    following[player.index] = nil
+end
+
+--- Used to stop all players following an entity or player
+function Public.stop_all()
+    for key, data in pairs(following) do
+        Public.stop_follow(data[1])
+    end
+end
+
+----- Gui -----
+
+--- Label used to show that the player is following, also used to allow esc to stop following
+-- @element follow_label
+follow_label =
+Gui.element(function(event_trigger, parent, target)
+    Gui.destroy_if_valid(parent[event_trigger])
+
+    local label = parent.add{
+        name = event_trigger,
+        type = 'label',
+        style = 'heading_1_label',
+        caption = 'Following '..target.name..'.\nClick here or press esc to stop following.'
+    }
+
+    local player = Gui.get_player_from_element(parent)
+    local res = player.display_resolution
+    label.location = {0, res.height-150}
+    label.style.width = res.width
+    label.style.horizontal_align = 'center'
+    player.opened = label
+
+    return label
+end)
+:on_close(Public.stop_follow)
+:on_click(Public.stop_follow)
+
+----- Events -----
+
+--- Updates the location of the player as well as doing some sanity checks
+-- @tparam LuaPlayer player The player to update the position of
+-- @tparam ?LuaPlayer|LuaEntity entity The player or entity being followed
+local function update_player_location(player, entity, old_position)
+    if player.character or not entity.valid then
+        Public.stop_follow(player)
+    elseif player.position.x ~= old_position.x or player.position.y ~= old_position.y then
+        Public.stop_follow(player)
+    else
+        player.teleport(entity.position, entity.surface)
+    end
+end
+
+--- Updates the locations of all players currently following something
+local function update_all()
+    for _, data in pairs(following) do
+        update_player_location(data[1], data[2], data[3])
+        data[3] = data[1].position
+    end
+end
+
+-- Update the location of all players each tick
+Event.add(defines.events.on_tick, update_all)
+
+-- Check for player leaving
+Event.add(defines.events.on_player_left_game, function(event)
+    local player = game.players[event.player_index]
+    Public.stop_follow(player)
+    for _, data in pairs(following) do
+        if data[2] == player then
+            Public.stop_follow(data[1])
+        end
+    end
+end)
+
+----- Module Return -----
+return Public