add pointing to objects and nodes

init.lua

@@ -1,4 +1,7 @@
 local MODNAME = core.get_current_modname()
+local MODPATH = core.get_modpath(MODNAME)
+
+local util = dofile(MODPATH .. DIR_DELIM .. "util.lua")
 
 local api = {}
 _G[MODNAME] = api
@@ -8,21 +11,41 @@ api.e = {}
 
 
 local function create_shared_environment(player_name)
-    local me = core.get_player_by_name(player_name)
     local magic_keys = {
         me = function()
             return core.get_player_by_name(player_name)
         end,
         my_pos = function()
-            local pos = here
+            local me = core.get_player_by_name(player_name)
+            local pos = vector.zero() -- FIXME use last command position
             if me:is_player() then
                 pos = me:get_pos()
             end
             return pos
         end,
-        this_obj = function()
+        point = function()
+            local me = core.get_player_by_name(player_name)
+            local pointed_thing = util.raycast_crosshair(me, 200, true, false)
+            if pointed_thing then
+                return pointed_thing.intersection_point
+            end
+            return me:get_pos()
         end,
-        this_node = function()
+        this_obj = function()
+            local me = core.get_player_by_name(player_name)
+            local pointed_thing = util.raycast_crosshair_to_object(me, 200)
+            if pointed_thing then
+                return pointed_thing.ref
+            end
+            return nil
+        end,
+        this_node_pos = function()
+            local me = core.get_player_by_name(player_name)
+            local pointed_thing = util.raycast_crosshair(me, 200, false, false)
+            if pointed_thing then
+                return pointed_thing.under
+            end
+            return vector.round(me:get_pos())
         end,
     }
 

util.lua

@@ -0,0 +1,78 @@
+
+-- get actual eye_pos of the player (including eye_offset)
+local function player_get_eye_pos(player)
+    local p_pos = player:get_pos()
+    local p_eye_height = player:get_properties().eye_height
+    p_pos.y = p_pos.y + p_eye_height
+    local p_eye_pos = p_pos
+    local p_eye_offset = vector.multiply(player:get_eye_offset(), 0.1)
+    local yaw = player:get_look_horizontal()
+    p_eye_pos = vector.add(p_eye_pos, vector.rotate_around_axis(p_eye_offset, {x=0,y=1,z=0}, yaw))
+    return p_eye_pos
+end
+
+
+-- return first thing player is pointing at
+local function raycast_crosshair(player, range, point_to_objects, point_to_liquids)
+    local p_eye_pos = player_get_eye_pos(player)
+    local to = vector.add(p_eye_pos, vector.multiply(player:get_look_dir(), range))
+    local ray = core.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
+            -- exclude the player themselves from the raycast
+            pointed_thing = ray:next()
+        else
+            return pointed_thing
+        end
+    end
+    -- FIXME return "nothing" pointed thing?
+    return nil
+end
+
+
+-- return first object
+local function raycast_crosshair_to_object(player, range)
+    local p_eye_pos = player_get_eye_pos(player)
+    local to = vector.add(p_eye_pos, vector.multiply(player:get_look_dir(), range))
+    local ray = core.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" then
+            if pointed_thing.ref ~= player then
+                return pointed_thing
+            end
+        end
+        pointed_thing = ray:next()
+    end
+    -- FIXME return "nothing" pointed thing?
+    return nil
+end
+
+
+
+
+-- get position and thing that player is pointing at or nil
+local function get_pointed_position(player, range, point_to_objects, point_to_liquids)
+    local pointed_thing = raycast_crosshair(player, range, point_to_objects, point_to_liquids)
+    local pointed_pos = nil
+    if pointed_thing then
+        if pointed_thing.type == "node" then
+            -- middle between "above" and "under"
+            pointed_pos = vector.multiply(vector.add(pointed_thing.above, pointed_thing.under), 0.5)
+        elseif pointed_thing.type == "object" then
+            -- TODO point at the middle of collision box? (or not, ground may be better)
+            pointed_pos = pointed_thing.ref:get_pos()
+        end
+    end
+    return pointed_pos, pointed_thing
+end
+
+
+local util = {
+    player_get_eye_pos = player_get_eye_pos,
+    raycast_crosshair = raycast_crosshair,
+    raycast_crosshair_to_object = raycast_crosshair_to_object,
+    get_pointed_position = get_pointed_position,
+}
+return util