Space Dodger

Chen Lin
/
Space Dodger
on 2 Nov 2026
2
36
12
1
9914
game.m
function g = game()
%GAME - Orbit Drift one-button space flight game
%   G = GAME() returns initialization, update, and rendering callbacks
%   for the contest harness. Tap SPACE or click to boost the rocket.
%   Fly through barrier gaps to score; tap after a crash to retry.
%
%   See also minihackContest.play, minihackContest.validate

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

function s = initState(ax)
%initState - Create the scene and pooled graphics
ax.XLim = [0 800];
ax.YLim = [0 600];
ax.YDir = 'reverse';
ax.Color = [0.025 0.035 0.08];
s.best = 0;
s.t = 0;
s.stars = [800*rand(1,95); 72+470*rand(1,95)];
s.depth = 0.3+rand(1,95);
s = resetRound(s);
cyan = [0.3 0.94 0.92];
muted = [0.48 0.57 0.7];
% A procedural nebula avoids external assets and file access.
[xx,yy] = meshgrid(linspace(0,1,400),linspace(0,1,300));
fog = exp(-((xx-0.75).^2/0.18+(yy-0.4).^2/0.2));
bg = cat(3,0.025+0.055*fog,0.035+0.03*fog,0.08+0.12*fog);
image(ax,[0 800],[0 600],bg,'HitTest','off','PickableParts','none');
a = linspace(0,2*pi,100);
makePatch(ax,620+87*cos(a),214+87*sin(a),[0.11 0.12 0.23], ...
    'EdgeColor',[0.24 0.23 0.38],'LineWidth',1.5);
makePatch(ax,643+68*cos(a),198+68*sin(a),[0.095 0.10 0.20]);
line(ax,620+133*cos(a),214+27*sin(a)-40*cos(a), ...
    'Color',[0.27 0.25 0.40],'LineWidth',2, ...
    'HitTest','off','PickableParts','none');
s.g.stars = scatter(ax,s.stars(1,:),s.stars(2,:), ...
    3+7*s.depth,[0.60 0.70 0.87],'filled', ...
    'HitTest','off','PickableParts','none');
for k = 1:4
    s.g.top(k) = makePatch(ax,zeros(1,8),zeros(1,8), ...
        [0.07 0.16 0.20],'EdgeColor',[0.20 0.47 0.52]);
    s.g.bottom(k) = makePatch(ax,zeros(1,8),zeros(1,8), ...
        [0.07 0.16 0.20],'EdgeColor',[0.20 0.47 0.52]);
    s.g.rim(k) = line(ax,nan,nan,'Color',cyan,'LineWidth',3, ...
        'HitTest','off','PickableParts','none');
end
s.g.flame = makePatch(ax,[0 0 0],[0 0 0],[1 0.53 0.29]);
s.g.ship = makePatch(ax,zeros(1,9),zeros(1,9),[0.87 0.95 1], ...
    'EdgeColor',cyan,'LineWidth',1.3);
s.g.window = makePatch(ax,zeros(1,30),zeros(1,30),cyan);
s.g.burst = scatter(ax,nan(1,24),nan(1,24),20,cyan,'filled', ...
    'HitTest','off','PickableParts','none');
% Opaque HUD strips keep text readable over the moving scene.
makePatch(ax,[0 800 800 0],[0 0 66 66],[0.03 0.045 0.09]);
makePatch(ax,[0 800 800 0],[550 550 600 600],[0.03 0.045 0.09]);
line(ax,[0 800 nan 0 800],[66 66 nan 550 550], ...
    'Color',[0.13 0.25 0.32],'HitTest','off','PickableParts','none');
makeText(ax,24,31,'ORBIT / DRIFT',13,cyan,'FontWeight','bold');
makeText(ax,24,575,'SPACE OR CLICK  /  BOOST',10,muted);
makeText(ax,776,575,'ONE BUTTON. INFINITE SPACE.',9,muted, ...
    'HorizontalAlignment','right');
s.g.score = makeText(ax,400,31,'0',25,[0.9 0.97 1], ...
    'HorizontalAlignment','center','FontWeight','bold');
s.g.best = makeText(ax,776,31,'BEST  00',11,muted, ...
    'HorizontalAlignment','right');
s.g.card = makePatch(ax,[175 625 625 175],[133 133 433 433], ...
    [0.035 0.055 0.11],'EdgeColor',[0.19 0.37 0.45]);
s.g.eyebrow = makeText(ax,400,172,'DEEP SPACE / FLIGHT 01',10,cyan, ...
    'HorizontalAlignment','center');
s.g.title = makeText(ax,400,227,'ORBIT DRIFT',32,[0.92 0.97 1], ...
    'HorizontalAlignment','center','FontWeight','bold');
s.g.subtitle = makeText(ax,400,283,'Small ship. A big universe.',13,muted, ...
    'HorizontalAlignment','center');
s.g.detail = makeText(ax,400,318,'Tap to rise. Coast to fall. Find the gap.',11, ...
    [0.68 0.77 0.86],'HorizontalAlignment','center');
s.g.button = makePatch(ax,[262 538 538 262],[358 358 407 407],cyan);
s.g.prompt = makeText(ax,400,382,'TAP TO LAUNCH',12,[0.03 0.09 0.13], ...
    'HorizontalAlignment','center','FontWeight','bold');
renderFrame([],s);
end

function s = resetRound(s)
%resetRound - Reset gameplay while retaining graphics and the best score
s.y = 300;
s.v = 0;
s.score = 0;
s.mode = 0;
s.boost = 0;
s.deadTime = 0;
s.gates = 850+(0:3)*250;
s.centers = [300 280 340 290];
s.gaps = 150*ones(1,4);
s.passed = false(1,4);
s.burstX = 190*ones(1,24);
s.burstY = 300*ones(1,24);
s.burstVX = zeros(1,24);
s.burstVY = zeros(1,24);
end

function s = updateState(s,dt,pressed)
%updateState - Apply tap boosts and integrate gravity and collision
s.t = s.t+dt;
s.stars(1,:) = mod(s.stars(1,:)-18*s.depth*dt,800);
s.boost = max(0,s.boost-dt);
if s.mode == 2
    s.deadTime = s.deadTime+dt;
    s.burstX = s.burstX+s.burstVX*dt;
    s.burstY = s.burstY+s.burstVY*dt;
    if pressed && s.deadTime > 0.55
        s = resetRound(s);
        s.mode = 1;
        s.v = -270;
        s.boost = 0.18;
    end
    return
end
if s.mode == 0
    s.y = 300+9*sin(2.4*s.t);
    if ~pressed
        return
    end
    s.mode = 1;
    s.y = 300;
end
if pressed
    s.v = -270;
    s.boost = 0.18;
end
% Small substeps prevent tunneling and make gravity frame-rate independent.
remaining = dt;
while remaining > 0 && s.mode == 1
    speed = 220+40*floor(s.score/10);
    h = min([remaining,1/120,6/speed]);
    remaining = remaining-h;
    s.y = s.y+s.v*h+0.5*720*h*h;
    s.v = s.v+720*h;
    s.gates = s.gates-speed*h;
    hit = s.y-14 <= 66 || s.y+14 >= 550;
    for k = 1:4
        % Circle versus rectangle matches the rocket's forgiving hitbox.
        dx = max([s.gates(k)-190,190-s.gates(k)-66,0]);
        top = s.centers(k)-s.gaps(k)/2;
        bottom = s.centers(k)+s.gaps(k)/2;
        hit = hit || dx^2+max(0,s.y-top)^2 <= 14^2 ...
            || dx^2+max(0,bottom-s.y)^2 <= 14^2;
    end
    if hit
        s.mode = 2;
        s.best = max(s.best,s.score);
        s.y = max(80,min(536,s.y));
        s.burstX(:) = 190;
        s.burstY(:) = s.y;
        a = (0:23)*2*pi/24;
        speed = 65+120*rand(1,24);
        s.burstVX = speed.*cos(a);
        s.burstVY = speed.*sin(a);
        return
    end
    for k = 1:4
        if ~s.passed(k) && s.gates(k)+66 < 176
            s.score = s.score+1;
            s.best = max(s.best,s.score);
            s.passed(k) = true;
        end
        if s.gates(k) < -80
            [far,j] = max(s.gates);
            s.gates(k) = far+250;
            s.gaps(k) = max(110,150-2*s.score);
            center = s.centers(j)+170*(rand-0.5);
            s.centers(k) = max(98+s.gaps(k)/2, ...
                min(518-s.gaps(k)/2,center));
            s.passed(k) = false;
        end
    end
end
end

function renderFrame(~,s)
%renderFrame - Update existing graphics without changing game state
s.g.stars.XData = s.stars(1,:);
s.g.stars.YData = s.stars(2,:);
for k = 1:4
    x = s.gates(k);
    top = s.centers(k)-s.gaps(k)/2;
    bottom = s.centers(k)+s.gaps(k)/2;
    outline = x+[0 66 66 56 56 10 10 0];
    s.g.top(k).XData = outline;
    s.g.top(k).YData = [66 66 top-18 top-18 top top top-18 top-18];
    s.g.bottom(k).XData = outline;
    s.g.bottom(k).YData = [550 550 bottom+18 bottom+18 ...
        bottom bottom bottom+18 bottom+18];
    s.g.rim(k).XData = x+[10 56 nan 10 56];
    s.g.rim(k).YData = [top top nan bottom bottom];
end
angle = max(-0.38,min(0.9,s.v/580));
if s.mode == 0
    angle = -0.12;
end
rot = [cos(angle) -sin(angle);sin(angle) cos(angle)];
p = rot*[25 11 -12 -23 -17 -17 -23 -12 11; ...
    0 -10 -10 -19 -5 5 19 10 10];
s.g.ship.XData = p(1,:)+190;
s.g.ship.YData = p(2,:)+s.y;
a = linspace(0,2*pi,30);
p = rot*[5+5*cos(a);5*sin(a)];
s.g.window.XData = p(1,:)+190;
s.g.window.YData = p(2,:)+s.y;
lengthFlame = 15+25*min(1,s.boost/0.18)+3*sin(40*s.t);
p = rot*[-17 -17 -17-lengthFlame;-5 5 0];
s.g.flame.XData = p(1,:)+190;
s.g.flame.YData = p(2,:)+s.y;
shipVisible = 'on';
if s.mode ~= 1
    shipVisible = 'off';
end
s.g.ship.Visible = shipVisible;
s.g.window.Visible = shipVisible;
s.g.flame.Visible = shipVisible;
s.g.burst.XData = s.burstX;
s.g.burst.YData = s.burstY;
s.g.burst.SizeData = max(1,32*(1-s.deadTime/0.8));
s.g.burst.Visible = 'off';
if s.mode == 2 && s.deadTime < 0.8
    s.g.burst.Visible = 'on';
end
s.g.score.String = sprintf('%d',s.score);
s.g.best.String = sprintf('BEST  %02d',s.best);
overlay = 'on';
if s.mode == 1 || (s.mode == 2 && s.deadTime < 0.55)
    overlay = 'off';
end
set([s.g.card s.g.eyebrow s.g.title s.g.subtitle s.g.detail ...
    s.g.button s.g.prompt],'Visible',overlay);
if s.mode == 0
    s.g.eyebrow.String = 'DEEP SPACE / FLIGHT 01';
    s.g.title.String = 'ORBIT DRIFT';
    s.g.subtitle.String = 'Small ship. A big universe.';
    s.g.detail.String = 'Tap to rise. Coast to fall. Find the gap.';
    s.g.prompt.String = 'TAP TO LAUNCH';
elseif s.mode == 2
    s.g.eyebrow.String = 'SIGNAL LOST / MISSION COMPLETE';
    s.g.title.String = 'NICE FLIGHT';
    s.g.subtitle.String = sprintf('%d GATES CLEARED   /   BEST %d', ...
        s.score,s.best);
    s.g.detail.String = 'The next run is yours.';
    s.g.prompt.String = 'TAP TO TRY AGAIN';
end
end

function p = makePatch(ax,x,y,color,varargin)
%makePatch - Create a click-through polygon in the supplied axes
p = patch(ax,x,y,color,'EdgeColor','none', ...
    'HitTest','off','PickableParts','none',varargin{:});
end

function t = makeText(ax,x,y,label,size,color,varargin)
%makeText - Create a click-through label in the supplied axes
t = text(ax,x,y,label,'FontSize',size,'Color',color, ...
    'FontName','Consolas','Interpreter','none', ...
    'VerticalAlignment','middle','HitTest','off', ...
    'PickableParts','none',varargin{:});
end
Play Game
Preview

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