feat(2048): add 2048 tile sliding game

apps/2048/README.md

@@ -0,0 +1,29 @@
+# 2048
+
+Slide tiles with the direction buttons; equal tiles merge and the score grows. A new 2 (or
+occasionally 4) appears after every move that changes the board. The game ends when the grid is full
+with no equal neighbours.
+
+## Controls
+
+| Button | Action |
+|---|---|
+| Up / Down / Left / Right | Slide the board |
+| Confirm | New game |
+| Back | Exit |
+
+## Notes
+
+- The best score is kept in `/.apps/2048/best.txt` and written on game over, new game, and exit.
+- Tile shade tracks magnitude (white → light gray → dark gray → black), which is the one place the
+  panel renders true grayscale via `gui.fillRoundedRect`.
+- Every move repaints the whole grid with `REFRESH_FAST`; the panel diffs frames, so only changed
+  tiles actually move.
+
+## Testing
+
+Logic runs off-device with stubbed firmware globals:
+
+```bash
+nix run nixpkgs#lua -- _scratch/test_2048.lua
+```

apps/2048/main.lua

@@ -0,0 +1,229 @@
+-- DESCRIPTION: Slide and merge tiles to reach 2048
+
+local SIZE = 4
+local CELLS = SIZE * SIZE
+local BEST_PATH = "/.apps/2048/best.txt"
+
+local board = {}
+local score = 0
+local best = 0
+local message = ""
+local won = false
+local gameOver = false
+local firstDraw = true
+local needsDraw = true
+
+local function loadBest()
+    local text = fs.readFile(BEST_PATH)
+    best = tonumber(text and text:match("%d+") or "") or 0
+end
+
+local function saveBest()
+    if score <= best then return end
+    best = score
+    fs.writeFile(BEST_PATH, tostring(best))
+end
+
+local function spawnTile()
+    local empty = {}
+    for index = 1, CELLS do
+        if board[index] == 0 then empty[#empty + 1] = index end
+    end
+    if #empty == 0 then return end
+    board[empty[math.random(#empty)]] = math.random(10) == 1 and 4 or 2
+end
+
+local function startGame()
+    for index = 1, CELLS do board[index] = 0 end
+    score = 0
+    won = false
+    gameOver = false
+    message = "Slide to merge"
+    firstDraw = true
+    needsDraw = true
+    spawnTile()
+    spawnTile()
+end
+
+-- Line Indices - Every move is the same left-slide over a row or column read in the right order.
+local function lineIndices(direction, line)
+    local vertical = direction == "up" or direction == "down"
+    local reversed = direction == "right" or direction == "down"
+
+    local indices = {}
+    for step = 1, SIZE do
+        local offset = reversed and SIZE + 1 - step or step
+        if vertical then
+            indices[step] = (offset - 1) * SIZE + line
+        else
+            indices[step] = (line - 1) * SIZE + offset
+        end
+    end
+    return indices
+end
+
+local function slide(values)
+    local packed = {}
+    for _, value in ipairs(values) do
+        if value ~= 0 then packed[#packed + 1] = value end
+    end
+
+    local out, gained, index = {}, 0, 1
+    while index <= #packed do
+        if packed[index] == packed[index + 1] then
+            local merged = packed[index] * 2
+            out[#out + 1] = merged
+            gained = gained + merged
+            index = index + 2
+        else
+            out[#out + 1] = packed[index]
+            index = index + 1
+        end
+    end
+    for position = #out + 1, SIZE do out[position] = 0 end
+
+    return out, gained
+end
+
+local function move(direction)
+    local moved = false
+
+    for line = 1, SIZE do
+        local indices = lineIndices(direction, line)
+        local values = {}
+        for step = 1, SIZE do values[step] = board[indices[step]] end
+
+        local slid, gained = slide(values)
+        score = score + gained
+        for step = 1, SIZE do
+            if board[indices[step]] ~= slid[step] then
+                board[indices[step]] = slid[step]
+                moved = true
+            end
+        end
+    end
+
+    return moved
+end
+
+local function hasMoves()
+    for index = 1, CELLS do
+        if board[index] == 0 then return true end
+        local column = (index - 1) % SIZE + 1
+        if column < SIZE and board[index] == board[index + 1] then return true end
+        if index + SIZE <= CELLS and board[index] == board[index + SIZE] then return true end
+    end
+    return false
+end
+
+local function step(direction)
+    if move(direction) then
+        spawnTile()
+        message = "Slide to merge"
+
+        if not won then
+            for index = 1, CELLS do
+                if board[index] >= 2048 then
+                    won = true
+                    message = "2048! Keep going"
+                end
+            end
+        end
+    else
+        message = "No room that way"
+    end
+
+    if not hasMoves() then
+        gameOver = true
+        message = "No moves - OK for a new game"
+        saveBest()
+    end
+
+    needsDraw = true
+end
+
+local function tileStyle(value)
+    if value >= 256 then return COLOR_BLACK, COLOR_WHITE end
+    if value >= 32 then return COLOR_DARK_GRAY, COLOR_WHITE end
+    if value >= 8 then return COLOR_LIGHT_GRAY, COLOR_BLACK end
+    return COLOR_WHITE, COLOR_BLACK
+end
+
+local function drawTile(value, x, y, size)
+    local fill, textColor = tileStyle(value)
+
+    if value == 0 then
+        gui.drawRoundedRect(x, y, size, size, 1, 6, COLOR_LIGHT_GRAY)
+        return
+    end
+
+    gui.fillRoundedRect(x, y, size, size, 6, fill)
+    gui.drawRoundedRect(x, y, size, size, 2, 6, COLOR_BLACK)
+
+    local label = tostring(value)
+    local font = FONT_NOTOSANS_16
+    if gui.getTextWidth(font, label, STYLE_BOLD) > size - 10 then font = FONT_NOTOSANS_12 end
+    local textWidth = gui.getTextWidth(font, label, STYLE_BOLD)
+    gui.drawText(font, x + math.floor((size - textWidth) / 2), y + math.floor(size / 2) - 10, label, textColor,
+        STYLE_BOLD)
+end
+
+local function render()
+    local width, height = gui.width(), gui.height()
+    local top = 86
+    local gap = 8
+    local size = math.min(
+        math.floor((width - 48 - gap * (SIZE - 1)) / SIZE),
+        math.floor((height - top - 80 - gap * (SIZE - 1)) / SIZE))
+    local gridWidth = size * SIZE + gap * (SIZE - 1)
+    local startX = math.floor((width - gridWidth) / 2)
+
+    gui.clear()
+    gui.drawCenteredText(FONT_NOTOSANS_16, 16, "2048", COLOR_BLACK, STYLE_BOLD)
+    gui.drawCenteredText(FONT_SMALL, 46, "Score " .. score .. "   Best " .. best, COLOR_BLACK, STYLE_REGULAR)
+    gui.drawCenteredText(FONT_SMALL, 64, message, COLOR_BLACK, STYLE_REGULAR)
+
+    for row = 1, SIZE do
+        for column = 1, SIZE do
+            drawTile(board[(row - 1) * SIZE + column],
+                startX + (column - 1) * (size + gap),
+                top + (row - 1) * (size + gap), size)
+        end
+    end
+
+    gui.drawButtonHints("<<", "New", "<", ">")
+    gui.refresh(firstDraw and REFRESH_HALF or REFRESH_FAST)
+    firstDraw = false
+    needsDraw = false
+end
+
+function init()
+    math.randomseed(sys.millis())
+    loadBest()
+    startGame()
+end
+
+function draw()
+    if input.wasPressed("back") then
+        saveBest()
+        sys.exit()
+        return
+    end
+
+    if input.wasPressed("confirm") then
+        saveBest()
+        startGame()
+    elseif not gameOver then
+        if input.wasPressed("left") then
+            step("left")
+        elseif input.wasPressed("right") then
+            step("right")
+        elseif input.wasPressed("up") then
+            step("up")
+        elseif input.wasPressed("down") then
+            step("down")
+        end
+    end
+
+    if needsDraw then render() end
+end

apps/2048/manifest.txt

@@ -0,0 +1,2 @@
+XTEINK-MANIFEST|1
+main.lua|6324|da9bc8bbe2153eb8ba85e295dbe5e4ec9f4b0c8df57c2fc3eec5ed2dc185bba1

catalog.txt

@@ -1,4 +1,5 @@
 XTEINK-CATALOG|1
+2048|Slide and merge tiles to reach 2048|apps/2048/manifest.txt|97|44ea59e862e09bb4ed034fc3fe9c280a13bb814bd6cc16670482bb3e34db0180
 AppStore|Install apps from public Xteink repositories|apps/AppStore/manifest.txt|192|2eb608b92de6bdeff4fc8ed447b9319f45c0d79d5d73b14db1ab5a92f91e42d4
 BinaryKeyboard|Two-button recursive keyboard experiment|apps/BinaryKeyboard/manifest.txt|97|893867dba0ae2725caca1eb56375c98c4dd00d351134aa129698c51f97e25690
 HomeAssistant|Home Assistant status cards|apps/HomeAssistant/manifest.txt|177|b38ca49804444fd383a505ce9c51680ad9b7443950d682ca1b9ef3047bff98a5