apps: play2048: Add the 2048 game application

2048 is a popular sliding block puzzle game in which tiles are combined
to make the number 2048.

It's one of the few games that are enjoyable to play on such a small
form factor.

This started as a port of a TkInter implementation of the 2048 game. I
implemented all of the TkInter APIs used by the game and it worked on
wasp-os without any code change in the game. However, the performance
was very poor and it consumed too much RAM. I have since reimplemented
the whole game from scratch and managed to achieve acceptable
performance, although more improvements could still be made.

Because names in Python can't start with numbers, I had some trouble
naming things. The module is called "ttfe" (two-thousand-forty-eight),
the class name is Play2048App, and the software.py entry is "Play 2048".

Signed-off-by: Miguel Rochefort <miguelrochefort@gmail.com>
[daniel@redfelineninja.org.uk: Renamed the python filename, normalized
the screenshot and included the app in the docs]
Signed-off-by: Daniel Thompson <daniel@redfelineninja.org.uk>

2 files changed, 234 insertions, 4 deletions

diff --git a/wasp/apps/play2048.py b/wasp/apps/play2048.py
new file mode 100644
index 0000000..63dd448
--- /dev/null
+++ b/wasp/apps/play2048.py
@@ -0,0 +1,229 @@
+# SPDX-License-Identifier: LGPL-3.0-or-later
+# Copyright (C) 2020 Miguel Rochefort
+"""Play 2048
+~~~~~~~~~~~~
+
+A popular sliding block puzzle game in which tiles are combined to make the
+number 2048.
+
+    .. figure:: res/2048App.png
+        :width: 179
+
+        Screenshot of the 2048 game application
+"""
+
+import wasp
+import icons
+import widgets
+import random
+import fonts
+from micropython import const
+
+SCREEN_SIZE = const(240)
+
+GRID_PADDING = const(8)
+GRID_SIZE = const(4)
+CELL_SIZE = const(50)
+
+GRID_BACKGROUND = const(0x942F)
+CELL_BACKGROUND = [0x9CB1, 0xEF3B, 0xEF19, 0xF58F, 0xF4AC, 0xF3EB, 0xF2E7, 0xEE6E, 0xEE6C, 0xEE4A, 0xEE27, 0xEE05]
+CELL_FOREGROUND = [0x9CB1, 0x736C, 0x736C, 0xFFBE, 0xFFBE, 0xFFBE, 0xFFBE, 0xFFBE, 0xFFBE, 0xFFBE, 0xFFBE, 0xFFBE]
+CELL_LABEL = ['','2','4','8','16','32','64','128','256','512','1K','2K'] # TODO: Display 1024 and 2048 (text-wrapping)
+
+# 2-bit RLE, generated from res/2048_icon.png, 785 bytes
+icon = (
+    b'\x02'
+    b'`@'
+    b'\x10\xbf\x01 \xbf\x01 \xbf\x01 \x83@\x81M\x82M'
+    b'\x82M\x82M\x83 \x83M\x82M\x82M\x82M\x83 '
+    b'\x83M\x82M\x82M\x82M\x83 \x83M\x82M\x82M'
+    b'\x82M\x83 \x83M\x82M\x82M\x82M\x83 \x83M'
+    b'\x82M\x82M\x82M\x83 \x83M\x82M\x82M\x82M'
+    b'\x83 \x83M\x82M\x82M\x82M\x83 \x83M\x82M'
+    b'\x82M\x82M\x83 \x83M\x82M\x82M\x82M\x83 '
+    b'\x83M\x82M\x82M\x82M\x83 \x83M\x82M\x82M'
+    b'\x82M\x83 \x83M\x82M\x82M\x82M\x83 \xbf\x01'
+    b' \xbf\x01 \x83M\x82M\x82M\x82\x80\xfb\x8d\xc0\xdb'
+    b'\xc3 \xc3M\xc2M\xc2M\xc2\x8d\xc3 \xc3M\xc2M'
+    b'\xc2M\xc2\x8d\xc3 \xc3M\xc2M\xc2M\xc2\x8d\xc3 '
+    b'\xc3M\xc2M\xc2M\xc2\x8d\xc3 \xc3M\xc2M\xc2M'
+    b'\xc2\x8d\xc3 \xc3M\xc2M\xc2M\xc2\x8d\xc3 \xc3M'
+    b'\xc2M\xc2M\xc2\x8d\xc3 \xc3M\xc2M\xc2M\xc2\x8d'
+    b'\xc3 \xc3M\xc2M\xc2M\xc2\x8d\xc3 \xc3M\xc2M'
+    b'\xc2M\xc2\x8d\xc3 \xc3M\xc2M\xc2M\xc2\x8d\xc3 '
+    b'\xc3M\xc2M\xc2M\xc2\x8d\xc3 \xff\x01 \xff\x01 '
+    b'\xc3\x8d\xc2M\xc2M\xc2@\xfaM\xc3 \xc3\x8d\xc2\x80'
+    b'\x81\x8d\xc2\x8d\xc2M\xc3 \xc3\xc0\xfb\xcd@\xdbB\x8d'
+    b'B\x8dB\x80\xfa\x8dC C\xcdB\xc0\x81\xcdB\xcd'
+    b'B\x8dC C@\xfbEA\x82AD\x80\xdb\x82\xcd'
+    b'\x82\xcd\x82\xc0\xfa\xcd\x83 \x83DAAAA\xc1A'
+    b'C\x82@\x81M\x82M\x82\xcd\x83 \x83\x80\xfb\x88\xc1'
+    b'\x81\x83\xc0\xdb\xc2M\xc2M\xc2@\xfaM\xc3 \xc3\x87'
+    b'\x81A\x81\x83\xc2\x80\x81\x8d\xc2\x8d\xc2M\xc3 \xc3\xc0'
+    b'\xfb\xc7A\xc1\xc4@\xdbB\x8dB\x8dB\x80\xfa\x8dC'
+    b' C\xc6\x81\xc1\xc5B\xc0\x81\xcdB\xcdB\x8dC '
+    b'C@\xfbE\x81AF\x80\xdb\x82\xcd\x82\xcd\x82\xc0\xfa'
+    b'\xcd\x83 \x83DA\xc4AC\x82@\x81M\x82M\x82'
+    b'\xcd\x83 \x83\x80\xfb\x8d\xc0\xdb\xc2M\xc2M\xc2@\xfa'
+    b'M\xc3 \xff\x01 \xff\x01 \xc3\x80\x81\x8d\xc2\xc0\xfb'
+    b'\xcd@\xdbB\x80\xf6\x8dB\xc0\xc8\xcdC C@\x81'
+    b'M\x80\xdb\x82\xc0\xfb\xcd\x82@\xf6M\x82\x80\xc8\x8d\xc0'
+    b'\xdb\xc3 \xc3@\x81M\xc2\x80\xfb\x8d\xc2\xc0\xf6\xcd@'
+    b'\xdbB\x80\xc8\x8dC C\xc0\x81\xcdB@\xfbM\x80'
+    b'\xdb\x82\xc0\xf6\xcd\x82@\xc8M\x83 \x83\x80\x81\x8d\xc0'
+    b'\xdb\xc2@\xfbM\xc2\x80\xf6\x8d\xc2\xc0\xc8\xcd@\xdbC'
+    b' C\x80\x81\x8dB\xc0\xfb\xcdB@\xf6M\x80\xdb\x82'
+    b'\xc0\xc8\xcd\x83 \x83@\x81M\x82\x80\xfb\x8d\xc0\xdb\xc2'
+    b'@\xf6M\xc2\x80\xc8\x8d\xc3 \xc3\xc0\x81\xcd@\xdbB'
+    b'\x80\xfb\x8dB\xc0\xf6\xcdB@\xc8M\x80\xdb\x83 \x83'
+    b'\xc0\x81\xcd\x82@\xfbM\x82\x80\xf6\x8d\xc0\xdb\xc2@\xc8'
+    b'M\xc3 \xc3\x80\x81\x8d\xc2\xc0\xfb\xcd@\xdbB\x80\xf6'
+    b'\x8dB\xc0\xc8\xcdC C@\x81M\x80\xdb\x82\xc0\xfb'
+    b'\xcd\x82@\xf6M\x82\x80\xc8\x8d\xc0\xdb\xc3 \xc3@\x81'
+    b'M\xc2\x80\xfb\x8d\xc2\xc0\xf6\xcd@\xdbB\x80\xc8\x8dC'
+    b' C\xc0\x81\xcdB@\xfbM\x80\xdb\x82\xc0\xf6\xcd\x82'
+    b'@\xc8M\x83 \xbf\x01 \xbf\x01 \xbf\x01\x10'
+)
+
+class Play2048App():
+    """Let's play the 2048 game."""
+    NAME = '2048'
+    ICON = icon
+
+    def __init__(self):
+        """Initialize the application."""
+        self._board = None
+        self._state = 0
+        self._confirmation_view = None
+
+    def foreground(self):
+        """Activate the application."""
+        wasp.system.request_event(wasp.EventMask.TOUCH |
+                                  wasp.EventMask.SWIPE_UPDOWN |
+                                  wasp.EventMask.SWIPE_LEFTRIGHT)
+
+        self._state = 0
+
+        if not self._board:
+            self._start_game()
+
+        self._draw()
+
+    def touch(self,event):
+        """Notify the application of a touchscreen touch event."""
+        if self._state == 0:
+            if not self._confirmation_view:
+                self._confirmation_view = widgets.ConfirmationView()
+            self._confirmation_view.draw('Restart game?')
+            self._state = 1
+        elif self._state == 1:
+            if self._confirmation_view.touch(event):
+                if self._confirmation_view.value:
+                    self._start_game()
+                self._draw()
+                self._state = 0
+
+    def swipe(self, event):
+        """Notify the application of a touchscreen swipe event."""
+        moved = False
+
+        if event[0] == wasp.EventType.UP:
+            moved = self._shift(1,False)
+        elif event[0] == wasp.EventType.DOWN:
+            moved = self._shift(-1,False)
+        elif event[0] == wasp.EventType.LEFT:
+            moved = self._shift(1,True)
+        elif event[0] == wasp.EventType.RIGHT:
+            moved = self._shift(-1,True)
+
+        if moved:
+            self._add_tile()
+
+    def _draw(self):
+        """Draw the display from scratch."""
+        board = self._board
+        draw = wasp.watch.drawable
+        draw.fill(GRID_BACKGROUND)
+        draw.set_font(fonts.sans24)
+        for y in range(GRID_SIZE):
+            for x in range(GRID_SIZE):
+                self._update(draw, board[y][x], y, x)
+
+    def _update(self, draw, cell, row, col):
+        """Update the specified cell of the application display."""
+        x = GRID_PADDING + (col * (CELL_SIZE + GRID_PADDING))
+        y = GRID_PADDING + (row * (CELL_SIZE + GRID_PADDING))
+        draw.set_color(CELL_FOREGROUND[cell], CELL_BACKGROUND[cell])
+        draw.fill(CELL_BACKGROUND[cell], x, y, CELL_SIZE, CELL_SIZE)
+        draw.string(CELL_LABEL[cell], x, y + 16, CELL_SIZE)
+
+    def _start_game(self):
+        """Start a new game."""
+        self._board = self._create_board()
+        self._add_tile()
+        self._add_tile()
+
+    def _create_board(self):
+        """Create an empty 4x4 board."""
+        board = []
+        for _ in range(GRID_SIZE):
+            board.append([0] * GRID_SIZE)
+        return board
+
+    def _add_tile(self):
+        """Add a new tile to a random empty location on the board."""
+        board = self._board
+        randint = random.randint
+        y = randint(0, GRID_SIZE-1)
+        x = randint(0, GRID_SIZE-1)
+        while board[y][x] != 0:
+            y = randint(0, GRID_SIZE-1)
+            x = randint(0, GRID_SIZE-1)
+        board[y][x] = 1
+        self._update(wasp.watch.drawable,1,y,x)
+
+    def _shift(self, direction, orientation):
+        """Shift and merge the tiles vertically."""
+        draw = wasp.watch.drawable
+        update = self._update
+        board = self._board
+        moved = False
+
+        def read(y, x):
+            if not orientation:
+                y,x = x,y
+            return board[y][x]
+
+        def write(y, x, v):
+            if not orientation:
+                y,x = x,y
+
+            board[y][x] = v
+            update(draw, v, y, x)
+
+        if direction > 0:
+            s = 0 + 1
+            e = GRID_SIZE
+        else:
+            s = GRID_SIZE - 1 - 1
+            e = 0 - 1
+
+        for y in range(GRID_SIZE):
+            p = s - direction
+            for x in range(s,e,direction):
+                a = read(y,x)
+                b = read(y,p)
+                if a != 0:
+                    if a == b:
+                        write(y, p, a + 1)
+                        write(y, x, 0)
+                        moved = True
+                        p += direction
+                    else:
+                        if b != 0:
+                            p += direction
+                        if x != p:
+                            write(y, p, a)
+                            write(y, x, 0)
+                            moved = True
+        return moved
diff --git a/wasp/apps/software.py b/wasp/apps/software.py
index b8bea2c..92a2531 100644
--- a/wasp/apps/software.py
+++ b/wasp/apps/software.py
@@ -19,10 +19,11 @@ class SoftwareApp():
                 ('fibonacci_clock', wasp.widgets.Checkbox(0, 120, 'Fibonacci Clock')),
                 ('gameoflife', wasp.widgets.Checkbox(0, 160, 'Game Of Life')),
                 ('musicplayer', wasp.widgets.Checkbox(0, 0, 'Music Player')),
-                ('snake', wasp.widgets.Checkbox(0, 40, 'Snake Game')),
-                ('flashlight', wasp.widgets.Checkbox(0, 80, 'Torch')),
-                ('testapp', wasp.widgets.Checkbox(0, 120, 'Test')),
-                ('timer', wasp.widgets.Checkbox(0, 160, 'Timer')),
+                ('play2048', wasp.widgets.Checkbox(0, 40, 'Play 2048')),
+                ('snake', wasp.widgets.Checkbox(0, 80, 'Snake Game')),
+                ('flashlight', wasp.widgets.Checkbox(0, 120, 'Torch')),
+                ('testapp', wasp.widgets.Checkbox(0, 160, 'Test')),
+                ('timer', wasp.widgets.Checkbox(0, 0, 'Timer')),
             )
         self.si = wasp.widgets.ScrollIndicator()
         self.page = 0