The Little Space Chimp

Mike Croucher
/
The Little Space Chimp
on 6 Nov 2026
3
30
7
0
9998
game.m
function g = game()
%game The Little Space Chimp -- a one-button zero-g banana hunt.
%   The chimp tumbles slowly in its bubble helmet. TAP to fire a jetpack
%   burst toward where its head points (the dashed guide); momentum
%   carries in zero-g and the screen wraps round. Bananas refuel the
%   jetpack (+1); a golden banana is worth 5 and fills the tank. Lumpy
%   asteroids drift about (more as you score) and from 5 bananas old
%   satellites tumble across. A hit cracks the helmet: three cracks and
%   the run ends. It also ends if the tank is too low to fire and no
%   banana is reached within 3 seconds.
%
%   Positions are complex (x + iy). Field key: md mode (0 title, 1 play,
%   2 game over), T time in mode, t clock, p/v chimp position/velocity,
%   a facing angle, fu fuel, fb flame timer, ot time unable to fire,
%   lf lives, iv blink (invulnerable) timer, sc bananas, bs best, wy why
%   the run ended; bananas bp position, bg golden; asteroids ao active,
%   ap/av position/velocity, aa/aw angle/spin, ar radius, A outlines;
%   satellites go active, gp/gv position/velocity, gt spawn timer;
%   jet puffs fp/fv/fa start/velocity/age; peel kp/kv/kt position/
%   velocity/time eaten; uS/uP/uT popup.
g.init = @initState;
g.update = @updateState;
g.render = @renderFrame;
end

function s = initState(ax)
Q = @(x, y, c, varargin) patch(ax, x, y, c, 'EdgeC', 'none', varargin{:});
L = @(varargin) line(ax, nan, nan, varargin{:});
C = @(z, varargin) Q(real(z), imag(z), varargin{:});
K = @(z, varargin) line(ax, real(z), imag(z), varargin{:});
T = @(x, y, varargin) text(ax, x, y, '', 'FontW', 'bold', 'FontN', 'Arial', 'Ho', 'center', varargin{:});
e = exp(2i * pi * (0:24) / 24);
% pastel sky, twinkling stars, a ringed planet and a moon
Q([0; 800; 800; 0], [0; 0; 600; 600], permute([.97 .8 .84; .97 .8 .84; .58 .52 .8; .58 .52 .8], [1 3 2]));
s.ss = 8 + 30 * rand(1, 70);
s.sh = 6 * rand(1, 70);
s.st = scatter(ax, 800 * rand(1, 70), 600 * rand(1, 70), s.ss, [1 1 1] - [0 .15 .05] .* (rand(70, 1) < .4), 'filled', 'MarkerFaceA', .9);
% the ring's far half goes behind the planet, its near half in front
r = 110 + 95i + (165 * real(e) + 28i * imag(e)) * exp(.25i);
R = {'Color', [.96 .9 1], 'LineW', 6};
K(r(1:13), R{:});
C(110 + 95i + 105 * e, [1 .8 .66]);
C(110 + 115i + 98 * real(e) + 16i * imag(e), [1 .88 .76]);
K(r(13:25), R{:});
C(690 + 500i + 32 * e, [1 .97 .82]);
K([680 + 508i, 702 + 494i, 690 + 488i], 'LineStyle', 'none', 'Marker', 'o', 'MarkerS', 8, 'MarkerFaceC', [.95 .9 .72], 'MarkerEdgeC', 'none');
% asteroids (8 lumpy 10-gons) and bananas (3 crescents)
s.ak = patch(ax, 'Verti', nan(80, 2), 'Faces', reshape(1:80, 10, 8)', 'FaceVertexCData', [.7 .62 .78] + .1 * rand(8, 3), 'FaceC', 'flat', 'EdgeC', [.42 .36 .52], 'LineW', 2);
s.bn = patch(ax, 'Verti', nan(48, 2), 'Faces', reshape(1:48, 16, 3)', 'FaceVertexCData', zeros(3, 3), 'FaceC', 'flat', 'EdgeC', [.6 .45 .15], 'LineW', 1.5);
s.sk = L('Color', [.45 .3 .12], 'LineW', 4);
% the peel left by an eaten banana: three floppy strips
s.pe = L('Color', [.95 .82 .35], 'LineW', 5);
s.P = [-16 - 12i, 9i, 16 - 12i, nan, 9i, -15i];
% banana: a curved pod, fat in the middle and pointed at both ends, with
% a stem continuing from one end
a = linspace(-2.4, -.75, 8);
w = 8 * sin(pi * (0:7) / 7) .^ .7 + 1;
s.B = [(30 + w) .* exp(1i * a), flip((30 - .7 * w) .* exp(1i * a))].' + 26i;
s.K = 30 * exp(-.75i) + 26i + [0; 8i * exp(-.75i)];
% satellites: a body, two solar panels and an antenna, each in a transform
for i = 1:2
    h = hgtransform(ax);
    s.gs(i) = h;
    patch([-10 10 10 -10], [-9 -9 9 9], [.92 .9 .96], 'EdgeC', [.45 .4 .55], 'LineW', 1.5, 'Parent', h);
    patch([-40 -13 -13 -40 nan 13 40 40 13], [-7 -7 7 7 nan -7 -7 7 7], [.6 .72 .96], 'EdgeC', [.35 .4 .6], 'LineW', 1.5, 'Parent', h);
    line([0 0], [9 20], 'Color', [.45 .4 .55], 'LineW', 2, 'Marker', 'o', 'MarkerIndices', 2, 'MarkerFaceC', [1 .6 .7], 'Parent', h);
end
% jet puffs, aiming guide
s.pf = scatter(ax, nan(1, 12), nan(1, 12), 30, [1 .93 .97], 'filled', 'MarkerFaceA', .7);
s.ai = L('Color', [1 1 1], 'LineStyle', '--', 'LineW', 2);
% the chimp: drawn facing +y inside a transform
h = hgtransform(ax);
s.cg = h;
E = @(x, y, a, b, c, varargin) patch((x + a .* real(e)).', (y + b .* imag(e)).', c, 'EdgeC', [.4 .28 .22], 'LineW', 1.5, 'Parent', h, varargin{:});
s.fl = patch([-7 7 0], [-24 -24 -46], [1 .7 .5], 'EdgeC', [1 .9 .6], 'LineW', 2, 'Parent', h);
patch([-6 6 6 -6], [-26 -26 -18 -18], [.7 .68 .8], 'Parent', h);
s.tl = line(nan, nan, 'Color', [.55 .36 .22], 'LineW', 3.5, 'Parent', h);
E([-13; 13], [-7; -7], 5, 7, 'w');
E(0, -10, 12, 13, 'w');
E([-11; 11], [10; 10], 4.5, 4.5, [.55 .36 .22]);
E(0, 9, 10, 10, [.55 .36 .22]);
E(0, 6, 7.5, 6, [.97 .85 .7]);
line([-3.5 3.5], [10 10], 'LineStyle', 'none', 'Marker', 'o', 'MarkerS', 4, 'MarkerFaceC', 'k', 'Parent', h);
line(3.5 * real(e(14:22)), 3 + 2 * imag(e(14:22)), 'Color', [.4 .28 .22], 'LineW', 1.5, 'Parent', h);
E(0, 6, 19, 19, [.8 .92 1], 'FaceA', .3, 'EdgeC', 'w', 'LineW', 2.5);
s.c1 = line([4 9 7 13], [14 9 5 2], 'Color', 'w', 'LineW', 2, 'Parent', h);
s.c2 = line([-6 -11 -9 -15], [20 16 12 10], 'Color', 'w', 'LineW', 2, 'Parent', h);
% HUD
s.fg = Q(nan, nan, [.6 .85 .7], 'EdgeC', 'w', 'LineW', 2);
s.sT = T(20, 575, 'FontS', 16, 'Color', [.35 .25 .5], 'Ho', 'left');
s.lT = T(780, 575, 'FontS', 22, 'Color', [.95 .5 .65], 'Ho', 'right');
s.po = T(0, 0, 'FontS', 16, 'Color', [.45 .3 .1]);
s.ms = T(400, 330, 'FontS', 17, 'Color', [.4 .28 .55], 'Ba', [1 .96 .98], 'EdgeC', [.95 .6 .75], 'Margin', 14, 'LineW', 3);
h = findall(ax);
set(h(2:end), 'Hi', 'off', 'Pi', 'none');
[s.t, s.bs] = deal(0);
s = resetRun(s);
end

function s = resetRun(s)
[s.md, s.T, s.v, s.fb, s.ot, s.iv, s.sc, s.wy, s.uT, s.uP] = deal(0);
[s.p, s.a, s.fu, s.lf, s.gt, s.uS, s.kp, s.kv, s.kt] = deal(400 + 300i, 0, 100, 3, 12, '', 0, 0, -9);
s.bp = 80 + 640 * rand(1, 3) + 1i * (80 + 440 * rand(1, 3));
[s.ao, s.go, s.bg] = deal(false(1, 8), false(1, 2), false(1, 3));
[s.ap, s.av, s.aa, s.aw, s.ar] = deal(zeros(1, 8));
[s.gp, s.gv] = deal(zeros(1, 2));
s.A = zeros(10, 8);
[s.fp, s.fv] = deal(zeros(1, 12));
s.fa = s.fp + 9;
end

function s = updateState(s, dt, pressed)
h = 1.1 * dt;                            % whole game runs 10% faster
s.t = s.t + h;
s.T = s.T + h;
s.uT = max(s.uT - h, 0);
s.fa = s.fa + h;
s.a = s.a + 2.4 * h;                    % the chimp tumbles steadily
W = @(z) mod(real(z), 800) + 1i * mod(imag(z), 600);
if s.md ~= 1
    if pressed && s.T > .8
        s = resetRun(s);
        s.md = 1;
    end
    return
end

% jetpack burst toward where the head points
s.fb = max(s.fb - h, 0);
s.iv = max(s.iv - h, 0);
u = exp(1i * s.a);
if pressed && s.fu >= 3
    [s.v, s.fu, s.fb] = deal(s.v + 110 * u, s.fu - 3, .25);
    [~, k] = sort(s.fa, 'descend');
    k = k(1:4);
    [s.fp(k), s.fv(k), s.fa(k)] = deal(s.p - 42 * u, -90 * u + 50 * (rand(1, 4) - .5) * 1i * u, 0);
end
s.v = s.v * min(1, 260 / max(abs(s.v), 1)) * (1 - .15 * h);
s.p = W(s.p + s.v * h);
s.ot = (s.ot + h) * (s.fu < 3);
if s.ot > 3
    s = over(s, 1);
    return
end

% bananas: refuel and respawn somewhere away from the chimp
for i = find(abs(s.bp - s.p) < 38)
    n = 1 + 4 * s.bg(i);
    [s.sc, s.fu] = deal(s.sc + n, min(100, s.fu + 15 + 100 * s.bg(i)));
    [s.uS, s.uP, s.uT, s.kp, s.kv, s.kt] = deal(sprintf('+%d', n), s.bp(i), 1, s.bp(i), -s.v / 2, s.t);
    q = 80 + 640 * rand + 1i * (80 + 440 * rand);
    s.bp(i) = W(q + 400 * (abs(q - s.p) < 200));
    s.bg(i) = rand < .12;
end

% asteroids: more of them as the score grows; they wrap like the chimp
i = find(~s.ao, 1);
if nnz(s.ao) < min(8, 2 + floor(s.sc / 4)) && any(i)
    q = (rand < .5) * 800 * rand + (rand < .5) * 600i * rand;
    q = q + (400 + 300i) * (abs(q - s.p) < 250);
    [s.ao(i), s.ap(i), s.ar(i), s.av(i), s.aw(i)] = deal(true, q, 12 + 16 * rand, min(90, 25 + 2 * s.sc + 20 * rand) * exp(2i * pi * rand), 2 * rand - 1);
    s.A(:, i) = s.ar(i) * (1 + .3 * (rand(10, 1) - .5)) .* exp(2i * pi * (0:9)' / 10);
end
s.ap = W(s.ap + s.av * h);
s.aa = s.aa + s.aw * h;
% satellites tumble across from 5 bananas on, and leave
s.gt = s.gt - h;
i = find(~s.go, 1);
if s.sc >= 5 && s.gt <= 0 && any(i)
    d = sign(rand - .5);
    [s.go(i), s.gp(i), s.gv(i), s.gt] = deal(true, 400 - 450 * d + 1i * (100 + 400 * rand), d * (60 + 40 * rand) + 20i * (rand - .5), 10 + 8 * rand);
end
s.gp = s.gp + s.gv * h;
s.go = s.go & abs(real(s.gp) - 400) < 460;
% hits crack the helmet
j = [s.ao & abs(s.ap - s.p) < 22 + .85 * s.ar, s.go & abs(s.gp - s.p) < 40];
if any(j) && ~s.iv
    z = [s.ap, s.gp];
    d = s.p - z(find(j, 1));
    [s.lf, s.iv, s.v] = deal(s.lf - 1, 2, 120 * d / abs(d));
    [s.uS, s.uP, s.uT] = deal('CRACK!', s.p, 1);
    if ~s.lf
        s = over(s, 2);
    end
end
end

function s = over(s, w)
[s.md, s.T, s.wy, s.bs] = deal(2, 0, w, max(s.bs, s.sc));
end

function renderFrame(~, s)
XY = @(h, z, varargin) set(h, 'XData', real(z), 'YData', imag(z), varargin{:});
M = @(a, k, z) [k * cos(a), -k * sin(a), 0, real(z); k * sin(a), k * cos(a), 0, imag(z); 0 0 1 0; 0 0 0 1];
set(s.st, 'SizeData', s.ss .* (1 + .6 * sin(2 * s.t + s.sh)));
% asteroids and bananas
Z = s.ap + s.A .* exp(1i * s.aa);
Z(:, ~s.ao) = nan;
set(s.ak, 'Verti', [real(Z(:)), imag(Z(:))]);
r = exp(.4i * sin(2 * s.t + (1:3)));
Z = s.bp + s.B .* r;
set(s.bn, 'Verti', [real(Z(:)), imag(Z(:))], 'FaceVertexCData', [1 .88 .3] + s.bg' * [0 -.13 -.2]);
Z = [s.bp + s.K .* r; nan(1, 3)];
XY(s.sk, Z(:));
% the latest peel spins away, shrinks and vanishes
a = s.t - s.kt;
XY(s.pe, s.kp + s.kv * a + (1 - a / 1.5) * s.P * exp(5i * a) + 0 ./ (a < 1.5));
% satellites
for i = 1:2
    set(s.gs(i), 'Matrix', M(.8 * s.t + i, 1, s.gp(i)), 'Vi', s.go(i));
end
% jet puffs grow and fade
XY(s.pf, s.fp + s.fv .* s.fa + 0 ./ (s.fa < .7), 'SizeData', 30 + 200 * min(s.fa, 1));
% the chimp: rotate so its head points along the facing angle
set(s.cg, 'Matrix', M(s.a - pi / 2, 1.5, s.p), 'Vi', ~s.iv || mod(s.t, .2) < .1);
set(s.fl, 'Vi', s.fb > 0);
% the curly tail sways as the chimp tumbles
XY(s.tl, cumsum([-20i, 3.5 * exp(1i * (.45 * sin(6 * s.t) - .9 + .045 * (0:10) .^ 2))]));
set([s.c1 s.c2], {'Vi'}, {s.lf < 3; s.lf < 2});
XY(s.ai, s.p + exp(1i * s.a) * [45 90], 'Vi', s.md == 1 && s.fu >= 3);
% HUD: fuel gauge, bananas, helmets left
w = 2 * s.fu;
XY(s.fg, 300 + [0 w w 0] + 1i * [566 566 584 584], 'FaceC', [.6 .85 .7] + (s.fu < 30) * [.35 -.25 0]);
set(s.sT, 'St', sprintf('BANANAS %d', s.sc));
set(s.lT, 'St', repmat(char(9679), 1, s.lf));
set(s.po, 'St', s.uS, 'Po', [real(s.uP), imag(s.uP) + 25 + 30 * (1 - s.uT)], 'Vi', s.uT > 0);
m = {['THE LITTLE SPACE CHIMP\n\nThe chimp tumbles slowly in zero-g.\nTap to fire the jetpack the way it faces.\n' ...
    'Grab bananas for fuel; dodge rocks and junk!\n\nTap to start'], '', ...
    '%s\n\nBananas %d    Best %d\n\nTap to fly again'};
q = {'OUT OF FUEL', 'HELMET BROKEN'};
set(s.ms, 'St', sprintf(m{s.md + 1}, q{max(s.wy, 1)}, s.sc, s.bs), 'Vi', s.md ~= 1);
end
Play Game
Preview

Play Game opens this in MATLAB Drive. Click Run this app there to play.