MoonRun

David
/
MoonRun
on 2 Nov 2026
5
75
27
1
9973
game.m
function g = game()
%game  MOONRUN - a one-button parallax runner under a moonlit sky.
%
%   SPACE (or click) jumps; press again in mid-air to double jump.
%   Jump spikes, rolling boulders and low-flying night birds; stay
%   grounded under high birds. Distance is your score.
%   
%   Built using Claude Code and Opus 5.5
%
%   >> minihackContest.validate
%   >> minihackContest.play
g.init   = @initState;
g.update = @updateState;
g.render = @renderFrame;
end

function s = initState(ax)
set(ax,'YDir','normal','XLim',[0 800],'YLim',[0 600],'ALim',[0 1],'Color','k','SortMethod','childorder');
E = {'EdgeColor','none'};

% Sky: vertical gradient, near-black zenith to violet horizon
strip(ax,[0 800],[.01 .01 .05],[.25 .16 .32]);

% Stars: random sizes, per-star twinkle rate and phase
n = 170;
s.sx = 800*rand(1,n); s.sw = 1+3*rand(n,1); s.sf = 7*rand(n,1);
s.sc = [.8 .85 1].*(.4+.6*rand(n,1));
s.h.st = scatter(ax,s.sx,220+380*rand(1,n),1+9*rand(1,n).^3,s.sc,'filled','MarkerEdgeColor','none');

% Moon: two soft radial glows and the disk
glow(ax,260,.16,0,[.75 .75 .95]);
glow(ax,90,.3,0,[.75 .75 .95]);
glow(ax,34,1,1,[.96 .94 .84]);

% Wispy clouds (one patch, four faces) drifting very slowly
t = linspace(0,2*pi,30)';
s.cv = repmat([120*cos(t) 12*sin(t).*(1+.4*sin(5*t))],4,1).*repelem(.6+rand(4,1),30);
s.cx = repelem(1400*rand(4,1),30); s.cy = repelem(330+220*rand(4,1),30);
s.h.cl = patch(ax,'Vertices',s.cv,'Faces',reshape(1:120,30,4)', ...
    'FaceColor',[.55 .5 .75],'FaceAlpha',.13,E{:});

% Three parallax ridges: [speed base height roughness shade]; nearer is darker
s.X = 0:8:800;
L = [.12 230 220 1.7 1; .3 160 190 1.5 .6; .55 100 170 1.3 .3];
s.rs = L(:,1);
for k = 1:3
    s.R{k} = L(k,2) + L(k,3)*nz(4096,L(k,4),12);
    s.h.r(k) = strip(ax,s.X,[.2 .16 .33]*L(k,5),[.13 .11 .25]*L(k,5));
    if k < 3   % mist band in front of the far and mid ridges
        y = [100 50; 300 220];
        patch(ax,[0 800 800 0],y(:,k)'*[1 1 0 0;0 0 1 1],[.32 .24 .42], ...
            'FaceVertexAlphaData',[.4;.4;0;0],'FaceAlpha','interp',E{:});
    end
end

% Gameplay terrain with a moonlit rim
s.T = 70 + 200*nz(8192,1.7,80);
s.X2 = 0:5:800;
s.h.tr = strip(ax,s.X2,[.03 .03 .07],[0 0 .01]);
s.h.rim = line(ax,s.X2,0*s.X2,'Color',[.5 .55 .85],'LineWidth',1.5);

% Obstacle pool: type 1 spike, 2 boulder, 3 bird (0 = free slot)
z = zeros(1,8);
[s.ot,s.ox,s.oy,s.ov,s.oh,s.oa,s.os] = deal(z);
for i = 1:8
    s.h.o(i) = patch(ax,'Vertices',zeros(9,2),'Faces',1:9,'EdgeColor',[.55 .6 .9],'LineWidth',1.2);
end

% Landing dust pool
z = zeros(1,30);
[s.dx,s.dy,s.dv,s.dw,s.dl] = deal(z);
s.h.du = scatter(ax,z,z,z+1,[.6 .6 .8],'filled','MarkerFaceAlpha',.5,'MarkerEdgeColor','none');

% Stick-figure runner: dark halo behind a pale body
q = {[.25 .22 .45] 7 15; [1 .92 .78] 2.5 9};
for k = 1:2
    s.h.ru(k) = line(ax,0,0,'Color',q{k,1},'LineWidth',q{k,2});
    s.h.hd(k) = line(ax,0,0,'Marker','o','MarkerSize',q{k,3},'MarkerFaceColor',q{k,1},'Color',q{k,1});
end


% Hit flash and HUD
s.h.fl = patch(ax,[0 800 800 0],[0 0 600 600],'w','FaceAlpha',0,E{:});
T = {'HorizontalAlignment','center','FontWeight','bold'};
s.h.sc = text(ax,20,575,'','Color',[.8 .85 1],'FontSize',15,T{3:4});
s.h.t1 = text(ax,400,380,'','Color',[1 .95 .85],'FontSize',40,T{:});
s.h.t2 = text(ax,400,330,'','Color',[.8 .82 1],'FontSize',14,T{1:2});
set(ax.Children,'HitTest','off','PickableParts','none');

s.t = 0; s.cam = 0; s.best = 0; s.fa = 0;
s = rst(s);
s.m = 0;   % 0 title, 1 playing, 2 dying, 3 game over
end

function s = updateState(s,dt,p)
s.t = s.t + dt;
s.fa = max(0,s.fa - 1.5*dt);
if p && ~mod(s.m,3)
    s = rst(s); p = 0;
end

% Speed: slow attract run on the title, ramps while playing, coasts to a stop on death
if s.m == 1
    s.rt = s.rt + dt;
    s.sp = min(520,250 + 6*s.rt);
    s.scr = s.scr + s.sp*dt/10;
elseif s.m
    s.sp = s.sp*exp(-2.5*dt);
    s.m = 3 - (s.t < s.td);
end
s.cam = s.cam + s.sp*dt;

% Runner physics
gx = gr(s,s.cam+200);
s.vy = s.vy - 1900*dt;
if s.m < 2
    if p && s.j < 2
        s.j = s.j + 1; s.vy = 760 - 80*s.j; s.on = 0;
        s.spin = 2*pi*(s.j > 1);
    end
    s.y = s.y + s.vy*dt;
    if s.y <= gx || (s.on && s.y-gx < 12 && s.vy <= 0)
        if ~s.on && s.vy < -400, s = dust(s); end
        s.y = gx; s.vy = 0; s.on = 1; s.j = 0; s.spin = 0;
    else
        s.on = 0;   % airborne: jumped or ran off a crest
    end
    s.ph = s.ph + s.on*s.sp*dt/16;
    s.spin = max(0,s.spin - 13*dt);
else
    s.y = s.y + s.vy*dt;
    s.rot = s.rot + 9*dt*min(1,abs(s.vy)/200);
    if s.y < gx, s.y = gx; s.vy = .35*abs(s.vy); end
end

% Spawn obstacles; approaching ones start further out so arrival timing is fair
s.st = s.st - dt;
i = find(~s.ot,1);
if s.m == 1 && s.st <= 0 && any(i)
    r = rand; l = min(1,s.rt/40);
    k = 1 + (r > .5-.25*l) + (r > .8-.1*l);
    v = [0 140+80*rand 100];
    s.ot(i) = k; s.ov(i) = v(k); s.oa(i) = 0; s.os(i) = 1 + 2*l*rand;
    s.ox(i) = s.cam + 200 + 660*(s.sp+v(k))/s.sp;
    s.oh(i) = 30 + 58*(rand < .45);
    s.st = max(.8,1.5 - s.rt/60) + .9*rand;
end

% Move, anchor to terrain, collide (runner = two circles at hip and chest)
s.ox = s.ox - s.ov*dt;
s.oa = s.oa + s.ov*dt./(15*s.os);
s.ot(s.ox < s.cam-60) = 0;
for i = find(s.ot)
    k = s.ot(i);
    y = [0 15*s.os(i) s.oh(i)+5*sin(4*s.t+i)];
    s.oy(i) = gr(s,s.ox(i)) + y(k);
    [X,Y] = meshgrid(s.cam+200+[-5 5],s.y+[3 20 40]); V = .85*shp(k,s.oa(i),14*s.t+i,s.os(i));
    if s.m == 1 && any(inpolygon(X(:),Y(:),V(:,1)+s.ox(i),V(:,2)+s.oy(i)))
        s.m = 2; s.td = s.t + 1.1; s.vy = 520; s.on = 0;
        s.fa = .55; s.best = max(s.best,s.scr); s = dust(s);
    end
end

% Dust particles live in screen space and scroll with the ground
s.dx = s.dx + (s.dv - s.sp)*dt;
s.dy = s.dy + s.dw*dt;
s.dw = s.dw - 150*dt;
s.dl = s.dl - dt;
end

function renderFrame(~,s)
h = s.h;
for k = 1:3
    h.r(k).Vertices = qv(s.X,smp(s.R{k},s.cam*s.rs(k)+s.X,4));
end
y = gr(s,s.cam+s.X2);
h.tr.Vertices = qv(s.X2,y);
h.rim.YData = y;
set(h.st,'XData',mod(s.sx-.02*s.cam,800),'CData',s.sc.*(.55+.45*sin(s.t*s.sw+s.sf)));
h.cl.Vertices = [mod(s.cx-.05*s.cam,1400)-200 s.cy] + s.cv;

for i = 1:8
    k = s.ot(i);
    set(h.o(i),'Visible',k>0);
    if k
        set(h.o(i),'Vertices',shp(k,s.oa(i),14*s.t+i,s.os(i))+[s.ox(i)-s.cam s.oy(i)], ...
            'FaceColor',(k==1:3)*[.12 .08 .16; .2 .17 .26; .04 .03 .08]);
    end
end

[P,H] = pose(s);
set(h.ru,'XData',P(:,1),'YData',P(:,2));
set(h.hd,'XData',H(1),'YData',H(2));

y = s.dy; y(s.dl <= 0) = NaN;
set(h.du,'XData',s.dx,'YData',y,'SizeData',max(s.dl,.01)*90);
h.fl.FaceAlpha = s.fa;

set(h.sc,'Visible',s.m>0,'String',sprintf('%d m     best %d m',floor(s.scr),floor(s.best)));
q = {'MOONRUN','SPACE to jump, again in mid-air to double jump'; '' ''; '' ''; ...
    'GAME OVER',sprintf('%d m   |   SPACE to run again',floor(s.scr))};
h.t1.String = q{s.m+1,1};
h.t2.String = q{s.m+1,2};
end

function s = rst(s)
% New round: keep scenery and best score, reset runner and hazards
s.m = 1; s.ot(:) = 0; s.dl(:) = 0;
s.rt = 0; s.scr = 0; s.st = 1.2; s.sp = 150;
s.y = gr(s,s.cam+200); s.vy = 0; s.on = 1;
[s.j,s.spin,s.ph,s.rot] = deal(0);
end

function s = dust(s)
i = find(s.dl <= 0,8); k = numel(i);
s.dx(i) = 200 + 6*randn(1,k); s.dy(i) = s.y + 2;
s.dv(i) = 80*randn(1,k); s.dw(i) = 40 + 60*rand(1,k);
s.dl(i) = .5 + .3*rand(1,k);
end

function [P,H] = pose(s)
% Stick figure in local coords (feet at origin), then rotate about the hip
q = s.ph + [0 pi];
th = .8*sin(q); kb = .2 + 1.1*max(0,sin(q+1.6)); u = -.9*sin(q);
if ~s.on && s.m < 2   % airborne tuck, arms up
    th = [1.1 .4]; kb = [1.7 1.2]; u = [2.5 -2];
end
d = @(a) [sin(a') -cos(a')];
hp = [0 24]; nk = hp + 18*d(pi-.3); H = nk + 7*d(pi-.3);
kn = hp + 12*d(th); ft = kn + 12*d(th-kb);
el = nk + 10*d(u); hn = el + 9*d(u+1.4);
P = [ft(1,:);kn(1,:);hp;kn(2,:);ft(2,:);NaN NaN;hn(1,:);el(1,:);nk;el(2,:);hn(2,:);NaN NaN;hp;nk;H];
a = s.spin + s.rot + .4*s.on*atan((gr(s,s.cam+210)-gr(s,s.cam+190))/20);
P = (P-hp)*[cos(a) sin(a);-sin(a) cos(a)] + hp + [200 s.y];
H = P(end,:); P(end,:) = [];
end

function V = shp(k,a,f,q)
% Obstacle outline (9 vertices) in local coords; q = size (spikes grow taller faster)
t = linspace(0,2*pi,9)' + a;
w = 13*sin(f);
V = {[-1 0;-.7 .9;-.45 .35;-.1 1.5;.25 .45;.55 1.05;.8 .3;1 0;1 0].*[13*q 17*q^1.5], ...
    16*q*[cos(t) sin(t)].*(1+.1*sin(3*t-a)), ...
    [-20 w;-8 4;0 8;8 4;20 w;10 -4;0 -3;-10 -4;-20 w]};
V = V{k};
end

function v = nz(n,a,k0)
% Periodic 1/f^a noise in [0,1]; frequencies below k0 removed
f = min(0:n-1,n:-1:1);
v = rescale(real(ifft(fft(randn(1,n)).*max(f,1).^-a.*(f>=k0))));
end

function y = smp(v,x,d)
% Circular linear interpolation of v (sample spacing d) at positions x
n = numel(v); u = x/d; i = floor(u); t = u - i;
i = mod(i,n) + 1;
y = v(i).*(1-t) + v(mod(i,n)+1).*t;
end

function y = gr(s,x)
y = smp(s.T,x,12);
end

function V = qv(X,y)
V = [X' y(:); X' 0*X'];
end

function h = strip(ax,X,ct,cb)
% Height-field patch with a top-to-bottom gradient per column
n = numel(X);
h = patch(ax,'Vertices',qv(X,600+0*X),'Faces',[1:n-1; 2:n; n+2:2*n; n+1:2*n-1]', ...
    'FaceVertexCData',[repmat(ct,n,1);repmat(cb,n,1)],'FaceColor','interp','EdgeColor','none');
end

function glow(ax,r,a,b,c)
% Radial fan around the moon: center alpha a, rim alpha b
t = linspace(0,2*pi,49)';
patch(ax,'Vertices',[610 470;610+r*cos(t) 470+r*sin(t)],'Faces',[0*t+1 (2:50)' [3:50 2]'], ...
    'FaceColor',c,'EdgeColor','none','FaceVertexAlphaData',[a;b+0*t],'FaceAlpha','interp');
end
Play Game
Preview

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