Box, Chomp, Boo - Retro Buffet - MATLAB One-Button Game Mini Hack

David Marshall
/
Box, Chomp, Boo - Retro Buffet
on 4 Nov 2026
4
21
8
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8471
game.m
function g = game()
%game Box, Chomp, Boo - Retro Buffet: a one-button sorting game.
%
%   Pets ride a belt through the sorting zone. Taps while a pet is in
%   the zone decide its fate: box a baby (it grows up on the shelf and
%   comes back), eat an adult, ignore a ghost. Mistakes escape and
%   nibble you. The first three pets are a tutorial: the belt waits.
%
%   LCD: 60x80 grid of palette indices drawn as one patch. Belt row 24,
%   zone cols 42-53, belt end col 58, shelf row 9.

g.init = @initState;
g.update = @updateState;
g.render = @renderFrame;
end

function s = initState(ax)
% Palette: 1 off, 2 ink, 3 tread, 4 escapee, 5 baby, 6 adult, 7 ghost,
% 8 box, 9 you
s.pal = [.74 .8 .62; .15 .19 .12; .45 .53 .38; .7 0 0; .93 .3 .6; .95 .55 .1; ...
	.5 .3 .85; .6 .38 .2; 0 .5 .55];
% Sprites as hex rows: baby, adult, ghost, box, you, you chomping
sp = @(h, w) dec2bin(hex2dec(reshape(h, ceil(w / 4), [])'), w) == '1';
s.spr = {sp('0C1E2D3F1E12', 6), sp('42667EDBFFBD7E42', 8), sp('1C3E6B6B7F7F7F552A', 7), ...
	sp('FF81FF999981FF', 8), sp('0F03FC7FE6F66F6FFFDFBE077FE3FC204606', 12), ...
	sp('0F03FC7FE6F66F6E07C03C036063FC204606', 12)};
s.sw = cellfun(@(m) size(m, 2), s.spr);
s.sh = cellfun(@(m) size(m, 1), s.spr);

C = ones(60, 80);
C(24, 2:58) = 2;
C(24:29, 58) = 2;
C(12:2:26, [42 53]) = 2;
C([12 26], 42:2:53) = 2;
C(9, 1:32) = 3;
s.base = C;

ax.XLim = [0 800]; ax.YLim = [0 600]; ax.YDir = 'reverse';
ax.Color = [.79 .84 .68];
o = {'HitTest', 'off', 'PickableParts', 'none'};
[c, r] = meshgrid(1:80, 1:60);
x = c(:) * 10 - 9; y = r(:) * 10 - 9;
s.g.lcd = patch(ax, 'Faces', (1:4800)' + [0 1 2 3] * 4800, ...
	'Vertices', [x y; x + 8 y; x + 8 y + 8; x y + 8], 'FaceVertexCData', C(:), ...
	'FaceColor', 'flat', 'CDataMapping', 'direct', 'EdgeColor', 'none', o{:});

f = {'FontName', 'FixedWidth', 'FontWeight', 'bold', 'HorizontalAlignment', 'center', ...
	'Color', s.pal(2, :), o{:}};
s.g.score = text(ax, 470, 28, '', 'FontSize', 16, f{:});
s.g.big = text(ax, 475, 65, '', 'FontSize', 36, f{:});
s.g.msg = text(ax, 400, 350, '', 'FontSize', 20, f{:});
s.g.btn = rectangle(ax, 'Position', [440 495 60 60], 'Curvature', 1, ...
	'EdgeColor', [.55 .4 .05], 'LineWidth', 3, o{:});

s.t = 0;
s = resetRound(s);
s.tut = 1;
end

function s = resetRound(s)
% Countdown timers T: 1 button, 2 fx text, 3 shake, 4 flash, 5 chomp,
% 6 retry lockout, 7 tutorial ghost wait
z = zeros(1, 12);
[s.px, s.py, s.act, s.taps, s.a, s.tx, s.ty] = deal(z);
s.k = z + 1;
s.T = zeros(1, 7);
[s.score, s.el, s.off, s.dist, s.gap, s.nib] = deal(0);
s.need = [1 2 0];
s.fx = ''; s.over = false; s.held = false; s.tut = 4;
end

function s = updateState(s, dt, pressed)
s.t = s.t + dt;
s.T = max(0, s.T - dt);
s.a = max(0, s.a - dt);
if pressed, s.T(1) = .12; end
if s.over
	if pressed && ~s.T(6), s = resetRound(s); end
	return
end

tut = s.tut < 4;
if tut
	spd = 12;
else
	s.el = s.el + dt;
	spd = min(28, 11 + .25 * s.el);
end
% Credit taps to the pet in the zone; tutorial caps them and holds the belt
c = s.px + s.sw(s.k) / 2;
i = find(s.act == 1 & c >= 42 & c <= 53, 1);
s.held = false;
if isempty(i) || c(i) < 47.5, s.T(7) = 1.5; end
if ~isempty(i)
	n = s.need(s.k(i));
	s.taps(i) = s.taps(i) + pressed;
	if tut && pressed && ~n
		s.T([2 3 7]) = [.5 .25 1.5]; s.fx = 'NO!';
	end
	if tut
		s.taps(i) = min(s.taps(i), n);
		s.held = c(i) >= 47.5 && (s.taps(i) < n || ~n && s.T(7) > 0);
	end
end
mv = spd * dt * ~s.held;
s.off = s.off + mv;

% Spawn: tutorial sends baby, adult, ghost one at a time. A ripe shelf box
% pauses new arrivals so it has room to drop
s.dist = s.dist + mv;
j = find(~s.act, 1);
if ~isempty(j) && (tut && ~any(s.act == 1) || ~tut && s.dist >= s.gap && ~any(s.act == 8 & ~s.a))
	s.act(j) = 1; s.taps(j) = 0;
	s.k(j) = randi(3); s.px(j) = -9; s.dist = 0; s.gap = 10 + randi(10);
	if tut, s.k(j) = s.tut; s.px(j) = 15; end
end

% Pet states: 1 unsorted, 2 sorted riding, 3 escaping, 4 falling,
% 5 crawling to you, 6 flying (to mouth or shelf), 7 ghost floating away,
% 8 boxed on shelf, 9 grown adult dropping onto belt
m = s.act > 0 & s.act < 4;
s.py(m) = 23;
m = m | s.act == 9;
s.px(m) = s.px(m) + mv;
c = s.px + s.sw(s.k) / 2;
for i = find(s.act == 1 & c > 53)
	s = resolvePet(s, i);
end
% Box closes, then flies to a free shelf slot (or ships if the shelf is full)
for i = find(s.act == 2 & s.k == 4 & ~s.a)
	f = setdiff([2 12 22], s.tx(ismember(s.act, [6 8]) & s.k == 4));
	s.act(i) = 0;
	if f, s.act(i) = 6; s.a(i) = .4; s.tx(i) = f(1); s.ty(i) = 8; end
end
m = s.act == 3 & c >= 58;
s.act(m) = 4;
m = s.act == 2 & c >= 58;
s.act(m) = 7 * (s.k(m) == 3);
m = s.act == 4;
s.py(m) = min(52, s.py(m) + 45 * dt);
s.act(m & s.py == 52) = 5;
m = s.act == 5;
s.px(m) = s.px(m) + 8 * dt;
m = m & s.px + s.sw(s.k) >= 65;
s.nib = s.nib + sum(m);
s.act(m) = 0;
m = s.act == 6 & ~s.a;
s.px(m) = s.tx(m); s.py(m) = s.ty(m);
if any(m & s.k == 2), s.T([2 5]) = [.7 .35]; s.fx = 'CHOMP!'; end
s.act(m) = 8 * (s.k(m) == 4);
s.a(m) = 6;
m = s.act == 7;
s.py(m) = s.py(m) - 20 * dt;
s.act(m & s.py < 0) = 0;
% Shelf box hatches into an adult once the belt below is clear, one at a time
for i = find(s.act == 8 & ~s.a)
	if ~any(s.act == 9 | s.act > 0 & s.act < 4 & s.px > s.px(i) - 16 & s.px < s.px(i) + 10)
		s.k(i) = 2; s.act(i) = 9;
	end
end
m = s.act == 9;
s.py(m) = s.py(m) + 60 * dt;
m = m & s.py >= 23;
s.act(m) = 1; s.taps(m) = 0;
if s.nib >= 5, s.over = true; s.T(6) = .6; end
end

function s = resolvePet(s, i)
k = s.k(i);
s.T(2) = .7;
if s.taps(i) ~= s.need(k)
	s.act(i) = 3; s.fx = 'OOPS!'; s.T(3:4) = [.3 .1];
	return
end
s.score = s.score + 10;
s.tut = s.tut + (s.tut < 4);
s.act(i) = 2; s.fx = 'BOO!';
if k == 1
	s.k(i) = 4; s.a(i) = .2; s.fx = 'BOXED!';
elseif k == 2
	s.act(i) = 6; s.a(i) = .4; s.tx(i) = 66; s.ty(i) = 52; s.fx = '';
end
if s.tut == 4 && ~s.el, s.fx = 'GO!'; end
end

function renderFrame(~, s)
C = s.base;
c = 2:57;
C(25, c(mod(c - floor(s.off), 4) < 2)) = 3;

% Zone goes solid while a pet is inside, with pips for taps so far
c = s.px + s.sw(s.k) / 2;
zi = find(s.act == 1 & c >= 42 & c <= 53, 1);
if zi
	C(12:26, [42 53]) = 2;
	C([12 26], 42:53) = 2;
	C(28:29, 45:46 + 3 * min(s.taps(zi), 3) - 3) = 2;
	C(28:29, 47:3:53) = 1;
end

for i = find(s.act)
	k = s.k(i); a = s.act(i); M = s.spr{k};
	x = s.px(i); y = s.py(i);
	if k == 3
		y = y - 2 + sin(s.t * 5 + i);
		if mod(s.t, .4) < .2, M = M([1:end - 2, end, end - 1], :); end
	elseif a == 1 || a == 5
		y = y - (mod(s.t * 4 + i, 1) < .5);
		x = x + (k == 1 && a == 1 && c(i) > 30) * ((mod(s.t * 30, 2) < 1) - .5);
	elseif a == 6
		u = 1 - s.a(i) / .4;
		x = x + (s.tx(i) - x) * u; y = y + (s.ty(i) - y) * u - 14 * sin(pi * u);
	elseif a == 8
		x = x + (s.a(i) < 1) * (mod(s.t * 20, 2) < 1);
	end
	if k == 4 && a == 2
		C = st(C, s.spr{1}, 17, x + 1, 5);
		y = y - 14 * s.a(i) / .2;
	end
	C = st(C, M, y - s.sh(k), x, 4 + k * (a < 3 || a > 5));
end

C = st(C, s.spr{5 + any(s.act == 6 & s.k == 2)}, 40 - (s.T(5) > 0), 66, 9);

% Pets nibbling you, and the danger meter
slots = [39 58; 46 58; 33 62; 33 72; 27 67];
for k = 1:min(s.nib, 5)
	C = st(C, s.spr{1}, slots(k, 1) - (mod(s.t * 6 + k, 1) < .5), slots(k, 2), 4);
end
b = 0:4;
C(2:4, 62 + [4 * b; 4 * b + 1; 4 * b + 2]) = 2;
C(2:4, 62 + [4 * b(b < s.nib); 4 * b(b < s.nib) + 1; 4 * b(b < s.nib) + 2]) = 4;
C(3, 63 + 4 * b(b >= s.nib)) = 1;

fl = s.T(4) > 0;
s.g.lcd.FaceVertexCData = C(:);
s.g.lcd.Parent.Colormap = s.pal([1 + fl, 2 - fl, 3:9], :);
s.g.lcd.Parent.XLim = [0 800] + 8 * sin(s.t * 90) * (s.T(3) > 0);

s.g.score.String = sprintf('SCORE %04d', s.score);
s.g.btn.FaceColor = [.85 .66 .2] + [.15 .26 .25] * (s.T(1) > 0);
hint = {'WAIT...', 'TAP!', 'TAP TAP!'};
b = '';
if s.T(2)
	b = s.fx;
elseif s.held && mod(s.t, .6) < .4
	b = hint{1 + s.need(s.k(zi))};
end
s.g.big.String = b;
s.g.big.Color = s.pal(2 + 2 * strcmp(b, 'OOPS!'), :);
m = '';
if s.over
	m = {'YOU WERE EATEN', sprintf('score %d  |  tap to retry', s.score)};
elseif s.tut == 1
	m = {'BOX, CHOMP, BOO', '\fontsize{14}retro buffet'};
end
s.g.msg.String = m;
end

function C = st(C, M, r, c, v)
% Paint mask M onto index grid C with its top-left at (r+1, c+1)
[y, x] = find(M);
y = y + round(r); x = x + round(c);
k = y > 0 & y <= 60 & x > 0 & x <= 80;
C(y(k) + 60 * (x(k) - 1)) = v;
end
Play Game
Preview

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