1 files changed, 163 insertions, 0 deletions
diff --git a/ch_core/active_objects.lua b/ch_core/active_objects.lua
new file mode 100644
index 0000000..45d80a7
--- /dev/null
+++ b/ch_core/active_objects.lua
@@ -0,0 +1,163 @@
+ch_core.open_submod("active_objects", {})
+
+local objects = {}
+-- [name] = {{/*current:*/ [key] = ObjRef, ...}, {/*prev*/ [key] = ObjRef, ...}}
+
+local function push_active_object(name, obj)
+    local key = tostring(obj)
+    local t = objects[name]
+    if t == nil then
+        objects[name] = {{[key] = obj}, {}}
+    else
+        t[1][key] = obj
+    end
+end
+
+local function on_step_default(self)
+    push_active_object(assert(self.name), assert(self.object))
+end
+
+local function try_append(dst, src)
+    for k, v in pairs(src) do
+        if dst[k] == nil and v:get_pos() ~= nil then
+            dst[k] = v
+        end
+    end
+end
+
+local function try_append_if_in_radius(dst, src, pos, radius)
+    assert(pos)
+    for k, v in pairs(src) do
+        if dst[k] == nil then
+            local v_pos = v:get_pos()
+            if v_pos ~= nil and vector.distance(pos, v_pos) <= radius then
+                dst[k] = v
+            end
+        end
+    end
+end
+
+--[[
+    Vrátí všechny aktivní objekty typu "name" v tabulce {[key] = ObjectRef}.
+    Platí pouze pro objekty používající ch_core.object_on_step() v poli on_step a hráčské postavy (name == "player").
+]]
+function ch_core.get_active_objects(names)
+    local result = {}
+    local t = type(names)
+    if t == "nil" then
+        -- return all objects
+        for _, lists in pairs(objects) do
+            try_append(result, lists[1])
+            try_append(result, lists[2])
+        end
+    elseif t == "string" then
+        -- single type of objects
+        local lists = objects[names]
+        if lists ~= nil then
+            try_append(result, lists[1])
+            try_append(result, lists[2])
+        end
+    elseif t == "table" then
+        for _, name in ipairs(names) do
+            local lists = objects[name]
+            if lists ~= nil then
+                try_append(result, lists[1])
+                try_append(result, lists[2])
+            end
+        end
+    else
+        error("Invalid type of argument: "..t)
+    end
+    return result
+end
+
+--[[
+local function append_if_inside_radius(dst, lists, pos, radius)
+    local new = {}
+    for i = 2, 1, -1 do
+        for key, obj in pairs(lists[i]) do
+            if new[key] == nil and vector.distance(obj:get_pos(), pos) <= radius then
+                new[key] = obj
+                dst[key] = obj
+            end
+        end
+    end
+end
+]]
+
+--[[
+    Vrátí aktivní objekty typu "name", pokud se nacházejí v zadané oblasti,
+    v tabulce {[key] = ObjectRef}.
+    Platí pouze pro objekty používající ch_core.object_on_step() v poli on_step a hráčské postavy (name == "player").
+]]
+function ch_core.get_active_objects_inside_radius(names, pos, radius)
+    local result = {}
+    local t = type(names)
+    if t == "nil" then
+        -- return all objects
+        for _, lists in pairs(objects) do
+            try_append_if_in_radius(result, lists[1], pos, radius)
+            try_append_if_in_radius(result, lists[2], pos, radius)
+        end
+    elseif t == "string" then
+        -- single type of objects
+        local lists = objects[names]
+        if lists ~= nil then
+            try_append_if_in_radius(result, lists[1], pos, radius)
+            try_append_if_in_radius(result, lists[2], pos, radius)
+        end
+    elseif t == "table" then
+        for _, name in ipairs(names) do
+            local lists = objects[name]
+            if lists ~= nil then
+                try_append_if_in_radius(result, lists[1], pos, radius)
+                try_append_if_in_radius(result, lists[2], pos, radius)
+            end
+        end
+    else
+        error("Invalid type of argument: "..t)
+    end
+    return result
+end
+
+--[[
+    Musí být zadána do pole on_step u objektů, které mají být hledány pomocí
+    funkcí z tohoto modulu.
+    orig_func - původní funkce on_step (bude volána), nebo nil
+]]
+function ch_core.object_on_step(orig_func)
+    if orig_func ~= nil then
+        return function(self, ...)
+            push_active_object(assert(self.name), assert(self.object))
+            return orig_func(self, ...)
+        end
+    else
+        return on_step_default
+    end
+end
+
+-- Globalstep
+local skip = true
+local function on_globalstep(dtime)
+    if skip then
+        skip = false
+        return
+    end
+    for _, name in pairs(objects) do
+        name[2] = name[1]
+        name[1] = {}
+    end
+    -- add players:
+    local players = {}
+    for _, player in ipairs(minetest.get_connected_players()) do
+        local key = tostring(player)
+        if players[key] ~= nil then
+            minetest.log("error", "Key duplicity in players table: "..player:get_player_name().." x "..players[key]:get_player_name().."!")
+        end
+        players[key] = player
+    end
+    objects.player = {players, {}}
+end
+minetest.register_globalstep(on_globalstep)
+
+ch_core.close_submod("active_objects")