Fireflies: Night Watch

Hans Scharler
/
Fireflies: Night Watch
about 22 hours ago
1
8
6
1
9996
game.m
function g=game()
% FIREFLIES: NIGHT WATCH. Shadows come out of the trees for the flame in a
% stone lantern. A swarm of fireflies wanders the meadow; tap to gather it
% into one blaze of light where it is, and the light drives the shadows off.
% A gather spends the swarm's rhythm: it needs time to fall back into step.
% Ground positions are complex numbers relative to the lantern (x right,
% y toward you); Z maps them to the screen. Screen positions are complex
% too (col + 1i*row, row 1 at the top).
% A is init, E update, P the night's play, F render. Helpers: K clamps to
% [0,1], M rounds and clamps, V is a flash curve, Q turns screen positions
% into pixel indices, W is the swarm's rhythm, J draws grass, Y builds the
% fog blur, D stamps a 91x91 patch, O turns a row into colour channels.
% State: l flame, s score, B best, N night time, x next shadow, o where the
% flies start from, e swarm path time, h home, w swarm offsets, C swarm
% centre, Z backdrop, D dawn glow, O what the grass leaves visible, y and z
% blur kernels, F flame glow, i image, T texts.
g.init=@A; g.update=@E; g.render=@F;
end

function s=A(ax)
% Blue hour: sky, four ridges fading into haze (spruce and hardwood crowns
% on the last), mist at the forest edge. Colour tables are strings, value + 32.
y=(1:600)'; x=1:800; z=O([66 62 104]/255);
B=O(interp1([0 190 320 372 392 600],reshape('#*<bxx%.>Vbb0Hb|zz'-32,[],3)/255,y));
L=['8HJv';'>:=`';':/2J';'(%&0']-32; w=4+7*rand(170,1); c=(x-800*rand(170,1))./w; a=rand(170,1)<.7;
T=max((12+30*rand(170,1)).*(a.*max(0,1-abs(c))+~a.*sqrt(max(0,1-(c/1.6).^2))));
for k=1:4
    r=sum(sin(.0102*(1:7)'.^1.35*x+7*rand(7,1))./(1:7)'.^1.15); r=300+36*k+L(k,1)*r/max(abs(r))-T*(k>3);
    m=.45*(k<4)*(1-exp((r-y)/45)); B=B+(y>=r).*(O(L(k,2:4))/255.*(1-m)+z.*m-B);
end
% Meadow grass (a short back band, a tall front band that hides what is
% behind it) and the stone lantern: roof, base, post, deck, box, finial.
B=(B.*(1-.5*K((y-470)/90))+.22*exp(-((y-468)/22).^2).*z).*(1-.6*J(500,476,56,10,20,.9));
S=y>=472&y<=481&abs(x-400)<=6+1.3*(y-472);
for v=reshape('[a0PN[<DJN4L>J7I05>B'-48,4,[])+[467;467;384;384], S(v(1):v(2),v(3):v(4))=1; end
B=B.*(1-S)+S*.07; s.O=1-.93*single(max(max(J(650,598,14,30,90,1.4),J(12,600,0,150,65,1)),S));
s.Z=255*single(B).*s.O+rand(600,800,3,'single')-.5;
% Stars, and the dawn glow.
r=rand(240,3); i=round(330*r(:,1).^1.4)+600*floor(800*r(:,2))+(0:2)*48e4+1; s.Z(i)=s.Z(i)+(.05+.55*r(:,3).^5).*[217 230 255];
s.D=single((exp(-((y-350)/80).^2)+.15*(y<420)).*O([200 80 70])).*s.O;
% Blur kernels: hot cores, green halo, and the wide fog (sampled every 8 px
% and blown back up with two dense matrices, ground mist weighted in).
s.y=exp(-(-3:3).^2/2.4)/2.746; s.z=exp(-(-24:24).^2/128)/20.05;
s.P=(.25+.75*exp(-((y-480)/70).^2)).*Y(y); s.Q=Y(x')';
% FIREFLIES as strokes: two chars per point (x, y in half units of 3.7 px),
% a space between strokes; a slash starts a letter. Sampled every 6 px.
H=[]; e=0;
for q=split('000D<D 0;9; /000D /000D7D:C<?:<7:0: 5:<0 /<D0D00=0 0;:; /000D<D 0;9; /0D00;0 /000D /<D0D00=0 0;:; /;A8D4D2A2=5;6::9;5:2603213')'
    v=q{1}-48; e=max([e (v(1)<0)*(max(real(H))+7)]); v=v(v>=0);
    z=e+v(1:2:end)+1i*(20-v(2:2:end)); r=[0 cumsum(abs(diff(z)))]; H=[H interp1(r,z,.8:1.62:r(end))]; %#ok<AGROW>
end
s.H=400+3.7*(H.'-max(real(H))/2)+172i; s.U=(-45:45)+1i*(-45:45)';
s.F=exp(-abs(s.U).^2/80).*O([255 160 70]);
% The meadow fireflies (first 240), then the title flight, which starts in
% the meadow and later becomes the swarm.
n=240+numel(s.H); s.p=800*rand(n,1)+1i*(395+195*rand(n,1).^.7); s.h=s.p; s.r=rand(n,1); s.b=.8+2.8*rand(n,1);
s.o=s.p(241:end); s.L=5.2+2.4*rescale(real(s.H))+.25*rand(n-240,1); s.w=46*sqrt(rand(n-240,1)).*exp(7i*rand(n-240,1));
for f='mtlsnNBGRkavfqe', s.(f)=0; end
[s.g,s.c,s.E]=deal(9,zeros(0,6),0*s.O);
% Text: score line, messages, loading line and rhythm, score popup.
s.i=image(ax,[.5 799.5],[599.5 .5],uint8(0*s.Z));
s.T=text(ax,[400 400 400 0],[578 440 38 0],'','FontSi',12,'Ho','c');
end

function U=Y(n)
% Wide blur on a grid sampled at 4:8:n, linearly upsampled back to n.
c=4:8:n(end); U=single(interp1(c,exp(-(c'-c).^2/5408)/16.3,M(n,4,c(end))));
end

function G=J(n,y,d,a,b,w)
% n grass blades from row y (+ up to d), a to a+b tall, w wide at the root.
t=(0:159)/159; h=a+b*rand(n,1).^2; G(600,800)=0;
q=800*rand(n,1)+.35*randn(n,1).*h.*t.^2+1i*(y+d*rand(n,1)-h.*t);
for o=-1:1, G(Q(q(:,abs(o)<=w*(1-t))+o))=1; end
end

function z=Z(w)
z=400+515i+real(w)+.45i*imag(w);
end

function s=E(s,h,p)
s.t=s.t+h; t=s.t; m=s.m;
if p&&(~m&&t>1.5||m>1&&s.a>.8)
    % Each night: faster shadows, more of them, and wilder kinds.
    k=(m==3)*s.n+1;
    [s.m,s.n,s.N,s.a,s.l,s.g,s.x,s.c,s.o,s.e,s.s]=deal(1,k,0,0,min(5,s.l+2+5*(k<2)),9,2.5,zeros(0,6),s.p(241:end),0,s.s*(k>1));
    return
end
s=P(s,h,p);
% Every firefly flashes every .95 s; how far each one is out of step falls
% with the rhythm W (the title's synchrony, or the swarm's after a gather).
n=numel(s.p); b=(1:n)'<241; k=241:n;
s.f=.95*mod(t/.95+(1-W(s)*~(b&m)).*s.r,1);
% Drift: a slow random walk held near home, with the climb while flashing
% (the J-stroke).
s.v=s.v-s.v*h/1.2+11*sqrt(h)*randn(n,2)*[1;1i]+h*(.05*real(s.h-s.p)+1.2i*imag(s.h-s.p)-32i*(s.f<.35));
s.p=s.p+s.v*h;
if m
    % The swarm: a loose cloud around a centre that loops around the
    % lantern. A gather pulls it into one ball, then it bursts apart.
    g=s.g; d=g-.8; o=s.w.*exp(1i*(1+2*s.r(k))*t);
    o=Z(s.C)+((d<0)*max(.12,1-14*g^2)+(d>=0)*(1+1.6*exp(-d/.5)-exp(-d/.12)))*(real(o)+.6i*imag(o));
    u=min(1,s.a/1.5+(s.n>1)); s.p(k)=s.o+(o-s.o)*u*u*(3-2*u); e=d<0&g>.15;
    I=[.6*V(s.f(b)); e*.45*s.q+~e*(.05+.45*V(s.f(k)))];
else
    % The title flight: a curved climb to its place on a letter.
    u=K((t-s.L)/1.7); u=u.*u.*(3-2*u); q=s.o+u.*(s.H+2*exp(1i*(3.6*t+7*s.r(k)))-s.o)-280i*u.*(1-u);
    a=t>s.L; s.p(k(a))=q(a); s.o(~a)=s.p(k(~a));
    I=V(s.f).*(t>s.b).*(.35+.65*K((imag(s.p)-390)/200)+1.1*~b)+.3*(t>[b(b)/0;s.L+1.7]);
end
% Exposure: each flash leaves light that fades over a quarter second.
s.E=s.E*exp(-4*h)+reshape(accumarray(Q(s.p),I,[48e4 1]),600,800)*h*20;
end

function c=W(s)
% The swarm's rhythm comes back after a gather; on the title, the meadow
% falls into step.
c=~~s.m*(1-exp(-max(0,s.g-.8)/1.6))+~s.m*K(s.t/3-.87);
end

function s=P(s,h,p)
% Runs on the title too, where nothing is out yet.
k=s.n; l=s.m==1; [s.N,s.g,s.a,s.e]=deal(s.N+h*l,s.g+h,s.a+h,s.e+h*(s.g+h>1.1));
% The swarm's centre loops near and far around the lantern; it waits while
% gathered. A gather's reach grows with the swarm's rhythm.
a=.62*s.e+.9*sin(.23*s.e); s.C=(.5+.45*sin(.31*s.e+1))*(330*cos(a)+140i*sin(a));
if p&&l&&s.g>.8, [s.g,s.G,s.R,s.k,s.q]=deal(0,s.C,40+110*W(s),0,W(s)); end
% New shadows from the trees and the sides; a pack comes four at a time.
% Columns: position, kind, birth, random, fade, flight velocity.
if l&&s.N>s.x&&s.N<55
    t=randi(min(4,k)); m=1+3*(t==4); a=pi*rand;
    s.c=[s.c; 430*cos(a)-1i*min(150,430*sin(a))+25*randn(m,2)*[1;1i], [t s.N 0 0 0]+(1:5==3).*rand(m,1)];
    s.x=s.N+max(.9,5.2*.84^(k-1))*(.6+.8*rand);
end
% Shadows come for the flame, faster as they get closer. Creepers sway,
% darters dash and freeze, lurkers circle (d) then lunge, packs twitch.
C=s.c; R=real(C); w=C(:,1); t=R(:,2); e=s.N-R(:,3); f=R(:,4); r=abs(w); b=R(:,5)==0; d=t==3&e<5+4*f&r<190;
u=-sign(w).*exp(1i*((t==1)*.35.*sin(1.1*e+6*f)+(t==2)*.9.*(-1).^floor(e/.95+f)+(t==4)*1.3.*sin(7*e+9*f))).*(1i*sign(f-.5)).^d;
v=13*1.1^(k-1)*(1+e/14+60./(r+60)).*(1+(t==2).*(3.4*(mod(e/.95+f,1)<.35)-.92)+.5*d+2.2*(t==3&e>=5+4*f)+.7*(t==4));
w=w+b.*(u.*v*h+1.2*k*sqrt(h)*randn(numel(w),2)*[1;1i])+~b.*C(:,6)*h;
% Caught in the light (g): it flees. Reaching the flame (i): the flame shrinks.
g=b&s.g>.15&s.g<.8&abs(w-s.G)<s.R; i=b&~g&r<18&l; c=nnz(g);
[s.s,s.k,s.l]=deal(s.s+10*k*sum(s.k+1:s.k+c),s.k+c,s.l-nnz(i));
C(:,[1 5 6])=[w, C(:,5)+(~b|g)*h+i, C(:,6)+300*g.*sign(w-s.G)];
if l&&(s.l<1||s.N>=60)
    % The flame is out, or dawn: the rest melt back into the trees.
    s.s=s.s+50*max(0,s.l)*k; [s.m,s.a,s.B]=deal(2+(s.l>0),0,max(s.B,s.s));
    C(:,5:6)=C(:,5:6)+(C(:,5)==0).*[h+0*w, 200*sign(w)];
end
s.c=C(C(:,5)<1,:);
end

function v=K(x)
v=min(1,max(0,x));
end

function v=M(x,a,b)
v=min(max(round(x),a),b);
end

function v=V(f)
v=min(f/.04,exp((.04-f)/.15));
end

function i=Q(q)
i=M(imag(q),1,599)+600*M(real(q),1,799)-600;
end

function F(~,s)
t=s.t; m=s.m;
% Light in two tone-mapped layers: hot cores and green bloom. The front
% grass hides what is behind it.
a=conv2(s.z,s.z,s.E,'same'); b=s.P*a(4:8:end,4:8:end)*s.Q; L=a+4*b;
X=s.Z*K(t/1.8)^1.6+.85*K(s.N/60)^2.5*s.D+s.O.*((1-exp(-4*conv2(s.y,s.y,s.E,'same'))).*O(255*[1 1 .72])+(1-exp(-16*a-70*b)).*O(255*[.55 .95 .2]));
% Where the last gather reached, and the flame in the lantern.
q=Q(Z(s.G+s.R*exp(.08i*(0:79)')))+(0:2)*48e4; X(q)=X(q)+.8*K(1-s.g)*[217 217 156];
X=D(X,Z(-62i),1,max(0,s.l)/5*(.85+.15*sin(23*t)*sin(7*t))*s.F);
% The shadows: hunched body, head, groping arms, smoky crown. You see
% them against the light; their eyes catch it. Each blob is a swing size,
% a swing rate and a rest place (strings, value + 48 or 32).
for C=s.c.'
    R=real(C); y=Z(C(1)); k=(imag(y)-350)/250*(1.2-.5*(R(2)==4));
    o=k*O(('02=#@ 54'-48).*sin((' R>B47zf'-32)/10*(s.N-R(3)+9*R(4)))+'006*8(00'-1i*'>PBA65Z4'-48+48i);
    v=.9*K(1-R(5)/.9)*K((s.N-R(3))/1.5);
    X=D(X,y,1-v*min(1,1.7*max(exp(-abs(s.U-o).^2./(2*k^2*O('<8443369'-48).^2)),[],3)),0);
    q=Q(y+o(2)+k*([-3.5 -2.5 2.5 3.5]-1.5i))+(0:2)'*48e4; X(q)=X(q)+v*min(1,.3+8*L(Q(y+o(2))))*[210;235;190];
end
% Text: messages (flame out, dawn, night, first night), then the loading
% lines, the score line and the popup. The rhythm is a line of dots (full
% means full reach).
w=split(sprintf('|THE FLAME IS OUT\n\nSCORE %d   BEST %d\n\n> TAP TO TRY AGAIN|DAWN\n\nNIGHT %d SURVIVED   SCORE %d\n\n> TAP FOR NIGHT %d|NIGHT %d|NIGHT 1\n\nSHADOWS ARE COMING FOR THE FLAME.\nTAP TO GATHER THE FIREFLIES.\nTHEIR LIGHT DRIVES THE SHADOWS OFF.| |NIGHTFALL|FINDING THE RHYTHM|> TAP TO BEGIN|NIGHT %d      SCORE %d|%d',s.s,s.B,s.n,s.s,s.n+1,s.n,s.n,s.s,10*s.n*s.k),'|');
i=~m*(1+(t>3.2)+(t>max(s.L)+1.7));
set(s.T,{'String'},{w{6+4*~~m};w{m+~m+(m==1&s.a<5)*(3+(s.n<2))};[w{6+i} 10 char(183+9496*((1:24)<=24*W(s)+.01))];w{6+5*(s.k&&s.g<1)}},...
    {'Color'},num2cell([.55;.85;~~m*(.5+.3*(W(s)>.99))+~m*K(t/.8-1.5)*(.65-.2*(i>2)*(1-V(s.f(1))));.8*K(1-s.g)]*[1 1 .72],2));
s.T(4).Position=[real(Z(s.G)) 640-imag(Z(s.G))];
s.i.CData=uint8(X);
end

function X=D(X,q,a,b)
% Scale by a, then add b, on the 91x91 patch at q.
r=M(imag(q),46,554)+(-45:45); c=M(real(q),46,754)+(-45:45);
X(r,c,:)=X(r,c,:).*a+b;
end

function v=O(x)
v=permute(x,[1 3 2]);
end
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