JAVASCRIPT
// This is a commented (or rather re-written) version of my JS1K 2018 entry - "Solar Quartet".
// This version has a better sky gradient and no audio at the moment.
// It's actually a remake of a demo I posted in 2011 on the now defunct wonderfl.net (which was something
// like codepen.io for ActionScript 3). That, in turn, was a fork of "Super Express", a train-ride scene
// by Me on CodePen.
// Currently in Chrome you need to click the "Get Adobe Flash" button so it'll ask you if you want to
// allow flash to run.
// The rest of this is formatted as:
// // Explanation of the compressed code
// // ...
//
// // Commented out, compressed code
//
// Readable (more or less) version of the code
// ...
document.addEventListener("DOMContentLoaded", go);
function go() {
"use strict";
// JS1K's HTML shim gives us a canvas (a) and its 2D context (c) for free. We'll set them up here.
let canvas = document.querySelector('canvas');
let ctx = canvas.getContext('2d');
// First off - we define an abbreviation function. This takes an object, iterates over its properties
// and stores their names as strings in a 2 or 3 letter variable ("this" is the window object).
//
// p[0]+p[6] will evaluate to the 1st and 7th letter (or the 1st+"undefined" if there's no 7th),
// [p[20]] will be an empty string if the property's name is too short ([undefined] gets coerced to
// an empty string).
//
// This is a variation on Marijn Haverbeke's technique - see https://marijnhaverbeke.nl/js1k/
//
// We won't be using it in the readable version of the demo.
// A=o=>{for(p in o)this[p[0]+p[6]+[p[20]]]=p}
// Next we abbreviate all the properties in our window object because requestAnimationFrame() is
// kind of long. We can't call A(window) because it will try to abbreviate all our abbreviations (since
// it stores them in the window object) so we'll use it on "top" which has the same properties.
// We really just need a shorter requestAnimationFrame().
//
// Sidenote: this is a clear violation of JS1K rules, which is why it's very important not to read them
// before the competition is over.
// A(top)
// Now, since our demo is fairly heavy we use a small canvas, but we want it to be fullscreen on a
// black background, so we waste ~90 bytes on some CSS to stretch it (currently "object-fit:contain"
// doesn't work for canvas on MS browsers).
//
// To avoid wasting 90 bytes just on this, we take this opportunity to define P and Q as 'width' and
// 'height' for later. This is probably a mistake since I ended up packing it with regpack anyway.
//
// The weird bit at the end is an ES6 template literal being abused to call the array's join method
// with something that will be coerced into the string ':100%;'.
// a.style=[P='width',Q='height','object-fit:contain;background:#000'].join`:100%;`
canvas.style = 'width: 100%; height: 100%; object-fit:contain; background:#000;';
// Now we need a frame counter.
// t=0
let frame = 0;
// B() is the requestAnimationFrame callback.
// B=_=>{
function onFrame() {
// Set width and height on our canvases, we'll be using a smaller canvas for the godrays. This
// also clears and resets their states. While we're at it, we'll store their dimensions in one
// letter vars for later.
// w=a[P]=512
// h=a[Q]=256
// W=E[P]=128
// H=E[Q]=64
canvas.width = 512;
canvas.height = 256;
godraysCanvas.width = 128;
godraysCanvas.height = 64;
// Set the sun's vertical position.
// T=C(t++/w)*24
let sunY = Math.cos(frame++ / 512) * 24; // This is actually the offset from the middle of the canvas.
// Get the 2D context for our godrays canvas, and create abbreviations for all the context properties.
// A(F=E.getContext`2d`)
let godraysCtx = godraysCanvas.getContext('2d');
// Now we set the godrays' context fillstyle (window.fy is 'fillStyle') to a newly created gradient
// (cr is 'createRadialGradient') which we also run through our abbreviator.
// A(F[fy]=g=F[cR](H,32+T,0,H,32+T,44)) // Could have shaved one more char here...
let emissionGradient = godraysCtx.createRadialGradient(
godraysCanvas.width / 2, godraysCanvas.height / 2 + sunY, // The sun's center.
0, // Start radius.
godraysCanvas.width / 2, godraysCanvas.height / 2 + sunY, // Sun's center again.
44 // End radius.
);
godraysCtx.fillStyle = emissionGradient;
// Now we addColorStops. This needs to be a dark gradient because our godrays effect will basically
// overlay it on top of itself many many times, so anything lighter will result in lots of white.
//
// If you're not space-bound you can add another stop or two, maybe fade out to black, but this
// actually looks good enough.
// g[ao](.1,'#0C0804')
// g[ao](.2,'#060201')
emissionGradient.addColorStop(.1, '#0C0804'); // Color for pixels in radius 0 to 4.4 (44 * .1).
emissionGradient.addColorStop(.2, '#060201'); // Color for everything past radius 8.8.
// Now paint the gradient all over our godrays canvas.
// F[fc](0,0,W,H)
godraysCtx.fillRect(0, 0, godraysCanvas.width, godraysCanvas.height);
// And set the fillstyle to black, we'll use it to paint our occlusion (mountains).
// F[fy]='#000'
godraysCtx.fillStyle = '#000';
// For our 1K demo, we paint our sky a solid #644 reddish-brown. But here - let's do it right.
// c[fy]=g='#644'
// c[fc](0,0,w,h)
let skyGradient = ctx.createLinearGradient(0, 0, 0, canvas.height);
skyGradient.addColorStop(0, '#2a3e55'); // Blueish at the top.
skyGradient.addColorStop(.7, '#8d4835'); // Reddish at the bottom.
ctx.fillStyle = skyGradient;
ctx.fillRect(0, 0, canvas.width, canvas.height);
// Our mountains will be made by summing up sine waves of varying frequencies and amplitudes.
// m=(f,j)=>[1721,947,547,233,73,31,7].reduce((a,v)=>a*j-C(f*v),0)
function mountainHeight(position, roughness) {
// Our frequencies (prime numbers to avoid extra repetitions).
let frequencies = [1721, 947, 547, 233, 73, 31, 7];
// Add them up.
return frequencies.reduce((height, freq) => height * roughness - Math.cos(freq * position), 0);
}
// Draw 4 layers of mountains.
// for(i=0;i<4;i++)for(X=w,c[fy]=`hsl(7,23%,${23-i*6}%`;X--;F[fc](X/4,U/4+1,1,w))c[fc](X,U=W+i*25+m((t+t*i*i)/1e3+X/2e3,i/19-.5)*45,1,w)
for(let i = 0; i < 4; i++) {
// Set the main canvas fillStyle to a shade of brown with variable lightness (darker at the front).
ctx.fillStyle = `hsl(7, 23%, ${23-i*6}%)`;
// For each column in our canvas...
for(let x = canvas.width; x--;) {
// Ok, I don't really remember the details here, basically the (frame+frame*i*i) makes the
// near mountains move faster than the far ones. We divide by large numbers because our
// mountains repeat at position 1/7*Math.PI*2 or something like that...
let mountainPosition = (frame+frame*i*i) / 1000 + x / 2000;
// Make further mountains more jagged, adds a bit of realism and also makes the godrays
// look nicer.
let mountainRoughness = i / 19 - .5;
// 128 is the middle, i * 25 moves the nearer mountains lower on the screen.
let y = 128 + i * 25 + mountainHeight(mountainPosition, mountainRoughness) * 45;
// Paint a 1px-wide rectangle from the mountain's top to below the bottom of the canvas.
ctx.fillRect(x, y, 1, 999); // 999 can be any large number...
// Paint the same thing in black on the godrays emission canvas, which is 1/4 the size,
// and move it one pixel down (otherwise there can be a tiny underlit space between the
// mountains and the sky).
godraysCtx.fillRect(x/4, y/4+1, 1, 999);
}
}
// The godrays are generated by adding up RGB values, gCt is the bane of all js golfers -
// globalCompositeOperation. Set it to 'lighter' on both canvases.
// c[gCt]=F[gCt]='lighter'
ctx.globalCompositeOperation = godraysCtx.globalCompositeOperation = 'lighter';
// NOW - let's light this motherfucker up! We'll make several passes over our emission canvas,
// each time adding an enlarged copy of it to itself so at the first pass we get 2 copies, then 4,
// then 8, then 16 etc... We square our scale factor at each iteration.
// for(s=1.07;s<5;s*=s)F[da](E,(W-W*s)/2,(H-H*s)/2-T*s+T,W*s,H*s)
for(let scaleFactor = 1.07; scaleFactor < 5; scaleFactor *= scaleFactor) {
// The x, y, width and height arguments for drawImage keep the light source (godraysCanvas.width
// / 2, godraysCanvas.height / 2 + sunY) in the same spot on the enlarged copy. It basically boils
// down to multiplying a 2D matrix by itself. There's probably a better way to do this, but I
// couldn't figure it out.
//
// For reference, here's an AS3 version (where BitmapData:draw takes a matrix argument):
// https://github.com/yonatan/volumetrics/blob/d3849027213e9499742cc4dfd2838c6032f4d9d3/src/org/zozuar/volumetrics/EffectContainer.as#L208-L209
godraysCtx.drawImage(
godraysCanvas,
(godraysCanvas.width - godraysCanvas.width * scaleFactor) / 2,
(godraysCanvas.height - godraysCanvas.height * scaleFactor) / 2 - sunY * scaleFactor + sunY,
godraysCanvas.width * scaleFactor,
godraysCanvas.height * scaleFactor
);
}
// Now that our godrays are rendered, draw them to our output canvas (whose globalCompositeOperation
// is already set to 'lighter').
// c[da](E,0,0,w,h)
ctx.drawImage(godraysCanvas, 0, 0, canvas.width, canvas.height);
// All done.
// this[rte](B)}
requestAnimationFrame(onFrame);
}
// Call our requestAnimationFrame handler to start rendering. Since it takes no arguments use the argument
// list to create our godrays canvas with cloneNode, which also takes no arguments... use it to setup a
// Math.cos shortcut (we'll skip this in our longform version).
// B(E=a.cloneNode(C=Math.cos))
let godraysCanvas = canvas.cloneNode();
onFrame();
// Phew... that took a while, but we're finally done with the visuals. Now for the audio part -
//
// The synthesizer is based on the Karplus-Strong algorithm which uses a very short delay loop as a
// resonator. I was initially aiming for a realistic string quartet but time and space constraints
// have forced me to massively compromise.
//
// To hear what a proper implementation can do, copy the MML (music macro language) from
// https://raw.githubusercontent.com/keim/SiONMML/4dba6d60ba1cb986c7de35dc7463c8af64c9c240/mmltalks/20120621_yonatan_Tomaso_Albinoni_Adagio_in_G_minor.sionmml
// paste it into http://wa.zozuar.org/code.php?c=yMPL (requires Flash) and press shift+enter to play.
//
// That's keim's SiON (https://github.com/keim/SiON), *the* AS3 audio library, which I've also used (very
// loosely) as a reference implementation.
//
// The music is a 64-note melody that ends up an octave above where it started, spread out in a 4-voice
// canon. We pre-render a single voice and then add up 4 in our ScriptProcessor callback.
// Big hairy render loop, let's break it to pieces and explain...
// for(M=[Y=[V=J=I=i=0]];i<h;i++)for(j=2e4;j--;T=Y[I|0]=M[J++]=O%9)O=Math.random()-.5+T/5+Y[(I=++I%(7e3/2**(("!!----,*,(444420/20/-0/---,,--//((4444202/;;;;986986420/00--//,,".charCodeAt(i&63)+12*(i>>6))/12)))|0]*.8||0
let encodedMelody = "!!----,*,(444420/20/-0/---,,--//((4444202/;;;;986986420/00--//,,";
// M=[Y=[V=J=I=i=0]]
let voiceBuffer = []; // M = [...]
let ksDelayBuffer = []; // Y = [...]
let sampleOffset = 0; // V = 0 (used later)
let J = 0; // What the hell is J????
// Oh fuck it. It's 4am and I have no idea how this thing works. Maybe I'll write it up later.
// Besides, you just came here for the godrays, right?
// A(G=new AudioContext)
// A(S=G[cSr](w*8,0,1))
// S[oo]=e=>{A(e);A(o=e[oB]);for(i=0;i<w*8;o[gn](0)[i++]=O/32,V++)for(O=0,K=4;K--;O+=T>0&&M[T%J])T=V-(K/32*9)*J}
// S.connect(G[da])
}
