basic announcement with a waypoint

init.lua

@@ -0,0 +1,100 @@
+-- TODO show some text on screen for a short while?
+-- TODO "admin" command version with configurable pos, radius and timeout
+
+local announce_command_name = "look!"
+local announce_radius = 256
+local announce_timeout = 20
+local waypoint_precision = 1 -- set to 1 to show whole number or 10 for 1 decimal
+local waypoint_color = 0xFFFFFF
+local point_range = 180
+local point_to_objects = true
+local point_to_liquids = true
+
+-- return first thing player is pointing at
+local function raycast_crosshair(player, range)
+    local p_pos = player:get_pos()
+    local p_eye_height = player:get_properties().eye_height
+    local p_eye_pos = { x = p_pos.x, y = p_pos.y + p_eye_height, z = p_pos.z }
+    local to = vector.add(p_eye_pos, vector.multiply(player:get_look_dir(), range))
+    local ray = minetest.raycast(p_eye_pos, to, point_to_objects, point_to_liquids)
+    local pointed_thing = ray:next()
+    while pointed_thing do
+        if pointed_thing.type == "object" and pointed_thing.ref == player then
+            pointed_thing = ray:next()
+        else
+            print("pointed_thing.type", pointed_thing.type)
+            return pointed_thing
+        end
+    end
+end
+
+
+local function get_pointed_position(player, range)
+    local pointed_thing = raycast_crosshair(player, range)
+    local pointed_pos = nil
+    if pointed_thing then
+        if pointed_thing.type == "node" then
+            pointed_pos = vector.multiply(vector.add(pointed_thing.above, pointed_thing.under), 0.5)
+        elseif pointed_thing.type == "object" then
+            pointed_pos = pointed_thing.ref:get_pos()
+        end
+    end
+    return pointed_pos, pointed_thing
+end
+
+
+local function show_hud_waypoint(player, point_pos, name)
+    local hud_id = player:hud_add({
+            hud_elem_type = "waypoint",
+            name = name,
+            text = "m", -- distance suffix
+            precision = waypoint_precision,
+            number = waypoint_color,
+            world_pos = point_pos,
+    })
+    return hud_id
+end
+
+
+local function hide_hud_waypoint(player_name, hud_id)
+    local player = minetest.get_player_by_name(player_name)
+    if player then
+        player:hud_remove(hud_id)
+    end
+end
+
+
+local function add_announcement(announcer, pos, radius, point_pos, name, timeout)
+     for i, object in pairs(minetest.get_objects_inside_radius(pos, radius)) do
+         if object:is_player() then
+             local player = object
+             local player_name = player:get_player_name()
+             local hud_id = show_hud_waypoint(player, point_pos, name)
+             minetest.after(announce_timeout, hide_hud_waypoint, player_name, hud_id)
+         end
+     end   
+end
+
+    
+minetest.register_chatcommand(announce_command_name, {
+    privs = {
+        shout = true,
+    },
+    func = function(name, param)
+        local player = minetest.get_player_by_name(name)
+        if player then          -- player is online
+            local player_pos = player:get_pos()
+            -- TODO use pointed thing to provide some description?
+            local pointed_pos, pointed_thing = get_pointed_position(player, point_range)
+            if not pointed_pos then
+                -- player is pointing into the void, use him as target
+                pointed_pos = player_pos
+            end
+            -- TODO limit message length?
+            add_announcement(player, player_pos, announce_radius, pointed_pos, param, announce_timeout)
+            return true, "Look at " .. minetest.pos_to_string(pointed_pos)
+        else
+            return false
+        end
+    end,
+})