Borrowed Light

YiXuan
/
Borrowed Light
on 13 Nov 2026
2
5
4
0
9881
game.m
function g = game()
% BORROWED LIGHT: turn a sculpture's shadow into a bridge with one tap.
% SPACE / click: begin, freeze the projection, retry, or continue.
g.init = @initState;
g.update = @updateState;
g.render = @renderFrame;
end

function s = initState(ax)
ax.XLim = [0 800];
ax.YLim = [0 600];
ax.YDir = 'reverse';
ax.Color = [0.97 0.95 0.90];
ax.DataAspectRatio = [1 1 1];
n = {'HitTest','off','PickableParts','none'};
ink = [0.19 0.22 0.24];
muted = [0.49 0.49 0.45];
orange = [0.89 0.36 0.16];
patch(ax,[400 155 645],[103 430 430],[1 0.98 0.83], ...
    'EdgeColor','none','FaceAlpha',0.55,n{:});
line(ax,[40 760],[91 91],'Color',[0.82 0.79 0.72],n{:});
text(ax,40,38,'BORROWED LIGHT','Color',ink,'FontSize',24, ...
    'FontWeight','bold','Interpreter','none',n{:});
text(ax,41,69,'Make a way home.', ...
    'Color',muted,'FontSize',11,n{:});
text(ax,40,125,'01 / SCULPTURE','Color',muted,'FontSize',9,n{:});
text(ax,40,345,'02 / SHADOW','Color',muted,'FontSize',9,n{:});
line(ax,[225 575],[430 430],'Color',[0.72 0.69 0.62], ...
    'LineStyle',':','LineWidth',1,n{:});
patch(ax,[0 225 225 206 167 116 58 0], ...
    [430 430 449 460 456 475 464 486],ink,'EdgeColor','none',n{:});
patch(ax,[575 800 800 747 688 643 599 575], ...
    [430 430 486 467 477 456 462 449],ink,'EdgeColor','none',n{:});
line(ax,[0 225 NaN 575 800],[429 429 NaN 429 429], ...
    'Color',[0.34 0.35 0.33],'LineWidth',3,n{:});
line(ax,[662 662],[430 382],'Color',ink,'LineWidth',2,n{:});
patch(ax,[663 687 663],[382 391 400],orange, ...
    'EdgeColor','none',n{:});
rectangle(ax,'Position',[392 96 16 10],'Curvature',0.4, ...
    'FaceColor',orange,'EdgeColor','none',n{:});
line(ax,[400 400],[92 96],'Color',ink,'LineWidth',2,n{:});
s.h.rods = gobjects(1,7);
s.h.shadows = gobjects(1,7);
s.h.rays = gobjects(1,7);
% Pools are created behind the player and only mutated later.
for k = 1:7
    s.h.rays(k) = line(ax,[0 0 NaN 0 0],[0 0 NaN 0 0], ...
        'Color',[0.85 0.80 0.64],'LineStyle',':',n{:});
    s.h.shadows(k) = patch(ax,zeros(1,4),zeros(1,4),ink, ...
        'EdgeColor','none',n{:});
    s.h.rods(k) = line(ax,[0 0],[0 0],'Color',ink, ...
        'LineWidth',8,n{:});
end
s.h.limbs = line(ax,NaN,NaN,'Color',orange,'LineWidth',3,n{:});
s.h.head = rectangle(ax,'Position',[162 393 14 14], ...
    'Curvature',[1 1],'FaceColor',orange,'EdgeColor','none',n{:});
s.h.scarf = patch(ax,[0 0 0],[0 0 0],orange,'EdgeColor','none',n{:});
s.h.level = text(ax,756,39,'','Color',muted,'FontSize',10, ...
    'HorizontalAlignment','right',n{:});
s.h.score = text(ax,756,66,'','Color',muted,'FontSize',10, ...
    'HorizontalAlignment','right',n{:});
s.h.status = text(ax,400,301,'','Color',ink,'FontSize',15, ...
    'HorizontalAlignment','center','FontWeight','bold',n{:});
s.h.detail = text(ax,400,325,'','Color',muted,'FontSize',10, ...
    'HorizontalAlignment','center',n{:});
s.h.prompt = text(ax,400,521,'','Color',ink,'FontSize',15, ...
    'HorizontalAlignment','center','FontWeight','bold',n{:});
s.h.hint = text(ax,400,552,'','Color',muted,'FontSize',10, ...
    'HorizontalAlignment','center',n{:});
s.h.dots = text(ax,400,580,'','Color',orange,'FontSize',10, ...
    'HorizontalAlignment','center','Interpreter','none',n{:});
s.level = 1;
s.score = 0;
s.attempts = 0;
s.totalTaps = 0;
s = newRound(s);
s.mode = 0;
renderFrame([],s);
end

function s = newRound(s)
s.count = min(7,3+s.level);
% At yaw zero the x intervals overlap. Separated depths break their
% projection apart at other angles, guaranteeing a solvable sculpture.
edges = linspace(-187,187,s.count+1);
s.ends = [edges(1:end-1)'-7 edges(2:end)'+7];
k = (1:s.count)';
s.depth = 90*sin(k*2.4+s.level*0.7);
s.angle = -1.05-0.07*s.level;
s.speed = 0.34+0.055*s.level;
s.clock = 0;
s.wait = 0;
s.mode = 1;
s.x = 170;
s.feet = 430;
s.vy = 0;
s.fallX = 0;
s.reward = 0;
s.attempts = s.attempts+1;
s = project(s);
end

function s = project(s)
% Orthographic view: yaw rotates x/depth, vertical light keeps shadow x.
c = cos(s.angle);
t = sin(s.angle);
s.px = 400+s.ends*c+s.depth*t;
s.py = 199+0.30*(-s.ends*t+s.depth*c);
s.spans = sort(s.px,2);
% Merge intervals from the left bank to measure actual walkable coverage.
v = sortrows(s.spans,1);
edge = 225;
s.gaps = 0;
for k = 1:s.count
    if v(k,2) <= 225 || v(k,1) >= 575, continue; end
    if v(k,1) > edge+0.01, s.gaps = s.gaps+1; end
    edge = max(edge,v(k,2));
end
if edge < 575, s.gaps = s.gaps+1; end
end

function s = updateState(s,dt,pressed)
s.clock = s.clock+dt;
s.wait = max(0,s.wait-dt);
if s.mode == 0
    s.angle = s.angle+s.speed*dt;
    s = project(s);
    if pressed
        s.angle = -1.12;
        s.mode = 1;
        s = project(s);
    end
elseif s.mode == 1
    s.angle = mod(s.angle+s.speed*dt+pi,2*pi)-pi;
    s = project(s);
    if pressed
        s.totalTaps = s.totalTaps+1;
        s.mode = 2;
        s.wait = 0.3;
    end
elseif s.mode == 2 && s.wait == 0
    % Sweep through intervals to catch even sub-frame gaps.
    goal = s.x+112*dt;
    v = sortrows([0 225; s.spans; 575 800],1);
    reach = s.x;
    for k = 1:size(v,1)
        if v(k,1) <= reach+0.01 && v(k,2) >= s.x
            reach = max(reach,v(k,2));
        end
    end
    if goal > reach+0.01
        s.x = reach;
        s.fallX = reach;
        s.mode = 3;
    else
        s.x = goal;
        if s.x >= 654
            s.mode = 5;
            s.wait = 0.5;
            s.reward = max(1,4-min(3,s.attempts));
            s.score = s.score+s.reward;
        end
    end
elseif s.mode == 3
    s.vy = s.vy+820*dt;
    s.feet = s.feet+s.vy*dt;
    s.x = min(s.fallX+18,s.x+24*dt);
    if s.feet > 650
        s.mode = 4;
        s.wait = 0.35;
    end
elseif s.mode == 4 && pressed && s.wait == 0
    s = newRound(s);
elseif s.mode == 5 && pressed && s.wait == 0
    if s.level == 6
        s.mode = 6;
    else
        s.level = s.level+1;
        s.attempts = 0;
        s = newRound(s);
    end
elseif s.mode == 6 && pressed
    s.level = 1;
    s.score = 0;
    s.attempts = 0;
    s.totalTaps = 0;
    s = newRound(s);
end
end

function renderFrame(~,s)
ink = [0.19 0.22 0.24];
green = [0.23 0.49 0.39];
preview = s.mode <= 1;
color = ink;
if preview, color = [0.60 0.59 0.53]; end
for k = 1:7
    if k <= s.count
        s.h.rods(k).Visible = 'on';
        s.h.shadows(k).Visible = 'on';
        s.h.rays(k).Visible = 'on';
        x = s.px(k,:);
        y = s.py(k,:);
        s.h.rods(k).XData = x;
        s.h.rods(k).YData = y;
        s.h.shadows(k).XData = [x fliplr(x)];
        s.h.shadows(k).YData = [430 430 439 439];
        s.h.shadows(k).FaceColor = color;
        s.h.rays(k).XData = [x(1) x(1) NaN x(2) x(2)];
        s.h.rays(k).YData = [y(1)+5 426 NaN y(2)+5 426];
    else
        s.h.rods(k).Visible = 'off';
        s.h.shadows(k).Visible = 'off';
        s.h.rays(k).Visible = 'off';
    end
end
x = s.x;
y = s.feet;
stride = 0;
if s.mode == 2 && s.wait == 0, stride = 5*sin(s.clock*16); end
s.h.head.Position = [x-7 y-37 14 14];
s.h.limbs.XData = x+[0 0 NaN -8 0 7 NaN -6-stride 0 6+stride];
s.h.limbs.YData = y+[-23 -10 NaN -15 -20 -15 NaN 0 -10 0];
s.h.scarf.XData = x+[-1 -21 -14];
s.h.scarf.YData = y+[-23 -26-2*sin(s.clock*4) -18];
s.h.level.String = sprintf('CHAPTER %02d / 06',s.level);
s.h.score.String = sprintf('LIGHT COLLECTED  %02d / 18',s.score);
s.h.dots.String = [repmat('+ ',1,s.level-1) repmat('. ',1,7-s.level)];
s.h.status.Color = ink;
if s.mode == 0
    a = 'Build a bridge out of light.';
    b = 'Watch the shadows.';
    p = 'TAP / SPACE TO BEGIN';
    h = 'Tap to freeze, then watch the crossing.';
elseif s.mode == 1
    if s.gaps == 0
        a = 'A path, for a moment.';
        s.h.status.Color = green;
    else
        a = sprintf('%d breaks in the shadow',s.gaps);
    end
    b = sprintf('SCULPTURE %02d  /  %d rods  /  attempt %d', ...
        s.level,s.count,s.attempts);
    p = 'TAP TO FREEZE THE SHADOW';
    h = 'Connect both banks.';
elseif s.mode == 2
    a = 'A little courage.';
    b = 'Will the shadow hold?';
    p = 'CROSSING';
    h = 'Every gap matters.';
elseif s.mode == 3 || s.mode == 4
    a = 'Almost. Light slipped through.';
    b = 'Look for gaps between both banks.';
    p = 'TAP TO RETRY';
    h = 'Completed chapters are kept.';
elseif s.mode == 5
    a = 'Closer to home.';
    s.h.status.Color = green;
    b = sprintf('CHAPTER COMPLETE   /   +%d LIGHT',s.reward);
    p = 'TAP TO CONTINUE';
    if s.level == 6, p = 'TAP TO GO HOME'; end
    h = 'First try = three lights.';
else
    a = 'You brought the light home.';
    s.h.status.Color = green;
    b = sprintf('SIX BRIDGES   /   %d LIGHT   /   %d PHOTOGRAPHS', ...
        s.score,s.totalTaps);
    p = 'TAP TO PLAY AGAIN';
    h = 'Welcome home.';
end
s.h.status.String = a;
s.h.detail.String = b;
s.h.prompt.String = p;
s.h.hint.String = h;
end
Play Game
Preview

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