From e8bb7306ac2dcc36db8904f92d10646161b55030 Mon Sep 17 00:00:00 2001
From: Ivan Yuriev <ivanyr44@gmail.com>
Date: Sun, 7 Sep 2025 14:27:02 +0300
Subject: [PATCH 1/2] Create priority_queue.lua

---
 lib/utils/priority_queue.lua | 106 +++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 lib/utils/priority_queue.lua

diff --git a/lib/utils/priority_queue.lua b/lib/utils/priority_queue.lua
new file mode 100644
index 0000000..89f2b32
--- /dev/null
+++ b/lib/utils/priority_queue.lua
@@ -0,0 +1,106 @@
+---@class PriorityQueue
+---@field private data any[]                   # внутренний массив-куча (индексация с 1)
+---@field private cmp fun(a:any, b:any):boolean  # компаратор: true, если a выше по приоритету, чем b
+local PriorityQueue = {}
+PriorityQueue.__index = PriorityQueue
+
+---Создать очередь с приоритетом.
+---@param cmp fun(a:any, b:any):boolean|nil  # если nil, используется a < b (мин-куча)
+---@return PriorityQueue
+function PriorityQueue.new(cmp)
+    local self = setmetatable({}, PriorityQueue)
+    self.data = {}
+    self.cmp = cmp or function(a, b) return a < b end
+    return self
+end
+
+-- ===== Внутренние утилиты =====
+
+---@param i integer @индекс узла
+---@param j integer @индекс узла
+function PriorityQueue:_swap(i, j)
+    self.data[i], self.data[j] = self.data[j], self.data[i]
+end
+
+---@param i integer
+function PriorityQueue:_sift_up(i)
+    while i > 1 do
+        local p = math.floor(i / 2)
+        if self.cmp(self.data[i], self.data[p]) then
+            self:_swap(i, p)
+            i = p
+        else
+            break
+        end
+    end
+end
+
+---@param i integer
+function PriorityQueue:_sift_down(i)
+    local n = #self.data
+    while true do
+        local l, r = i * 2, i * 2 + 1
+        local best = i
+
+        if l <= n and self.cmp(self.data[l], self.data[best]) then
+            best = l
+        end
+        if r <= n and self.cmp(self.data[r], self.data[best]) then
+            best = r
+        end
+
+        if best ~= i then
+            self:_swap(i, best)
+            i = best
+        else
+            break
+        end
+    end
+end
+
+-- ===== Публичный API =====
+
+---Вставка элемента.
+---@param x any
+function PriorityQueue:insert(x)
+    table.insert(self.data, x)
+    self:_sift_up(#self.data)
+end
+
+---Посмотреть первый элемент без удаления.
+---@return any|nil
+function PriorityQueue:peek()
+    return self.data[1]
+end
+
+---Извлечь первый элемент (корень кучи).
+---@return any|nil
+function PriorityQueue:pop()
+    local n = #self.data
+    if n == 0 then return nil end
+
+    local top = self.data[1]
+    local last = self.data[n]
+    self.data[n] = nil
+
+    if n > 1 then
+        self.data[1] = last
+        self:_sift_down(1)
+    end
+
+    return top
+end
+
+---Текущее количество элементов.
+---@return integer
+function PriorityQueue:size()
+    return #self.data
+end
+
+---Пуста ли очередь.
+---@return boolean
+function PriorityQueue:is_empty()
+    return #self.data == 0
+end
+
+return PriorityQueue

From 5cead3c28291a1785797ec0741342437535a0013 Mon Sep 17 00:00:00 2001
From: Ivan Yuriev <ivanyr44@gmail.com>
Date: Sun, 7 Sep 2025 14:27:20 +0300
Subject: [PATCH 2/2] fixed character z-ordering while moving

---
 lib/level/grid/character_grid.lua | 10 ++++++++++
 lib/level/level.lua               |  6 +++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/lib/level/grid/character_grid.lua b/lib/level/grid/character_grid.lua
index 1c51d2c..0192f1e 100644
--- a/lib/level/grid/character_grid.lua
+++ b/lib/level/grid/character_grid.lua
@@ -1,6 +1,8 @@
 local utils = require "lib.utils.utils"
+local pQueue = require "lib.utils.priority_queue"
 --- @class CharacterGrid : Grid
 --- @field __grid {string: Id|nil}
+--- @field yOrderQueue PriorityQueue<Character> очередь отрисовки сверху вниз
 local grid = setmetatable({}, require "lib.level.grid.base")
 grid.__index = grid
 
@@ -21,13 +23,21 @@ function grid:add(id)
     end
 end
 
+--- @param a Character
+--- @param b Character
+local function drawCmp(a, b)
+    return a.logic.mapLogic.displayedPosition.y < b.logic.mapLogic.displayedPosition.y
+end
+
 --- fills the grid with the actual data
 ---
 --- should be called as early as possible during every tick
 function grid:reload()
     self:reset()
+    self.yOrderQueue = pQueue.new(drawCmp)
     utils.each(Tree.level.characters, function(c)
         self:add(c.id)
+        self.yOrderQueue:insert(c)
     end)
 end
 
diff --git a/lib/level/level.lua b/lib/level/level.lua
index 1c603ff..6362402 100644
--- a/lib/level/level.lua
+++ b/lib/level/level.lua
@@ -39,9 +39,9 @@ end
 
 function level:draw()
     self.tileGrid:draw()
-    utils.each(self.characters, function(el)
-        el:draw()
-    end)
+    while not self.characterGrid.yOrderQueue:is_empty() do -- по сути это сортировка кучей за n log n, но линейное 
+        self.characterGrid.yOrderQueue:pop():draw()
+    end
 end
 
 return {