JS1k: The JavaScript code golfing competition

function t(t,e){return t+Math.random()*(e-t)}function e(){setTimeout(function(){var t,i,o;x+=h,z+=p,x>s&&(x=-u,z=0);for(t in M){for(g=parseInt(t),r.fillStyle="#F8"+g.toString(16),o=u/d,r.fillRect(0,t*o,s,(t+1)*o),t%2==0&&(c=l*c),v=c*T*Math.sin(z),r.fillStyle="#000",r.beginPath(),r.moveTo(M[t][0]+x,M[t][1]-v),i=2;9>i;i+=2)r.lineTo(M[t][i]+x,M[t][i+1]);r.closePath(),r.fill()}for(o in m)m[o].o=20*Math.abs(Math.sin(z)),px=m[o].x,r.beginPath(),r.moveTo(y+px,u),r.quadraticCurveTo(10+px,100,y+px+m[o].o,200),r.stroke();e()},1e3/n)}var o,n,r=window.c,a=new AudioContext,c=1,l=-1,s=1920,u=s/2,x=-u,v=z=0,h=3,p=.2,T=17,d=15,m=[],P=240,y=20,M=[];for(_P=[18,5,31,5,41,0,5,5],M[0]=_P,i=1;i<=P;i++){if(m[i-1]={x:t(0,s),o:t(0,1.5)},i<=d)for(cstx=t(90,u/3),M[i]=[],o=0;8>o;o++)M[i][o]=M[0][o]+cstx;i<3&&setInterval(function(){var t,e;for(f=[0,4e3,.2,.3,12e3,.6,.6,1e4,.8],t=0;7>t;t+=3)e=a.createOscillator(),e.frequency.value=f[t+1],e.type="square",e.connect(a.destination),e.start(f[t]),e.stop(a.currentTime+f[t+2])},2300*i)}n=30,e();

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/**
 *  @file javascript into shim.html
 *  @version 2017-02-27-09-36-00
 *  @date 2017/02/27
 *  @author Patrice CHASSAING
 *  @copyright Me
 *  @brief JS1k 2017 demo contest
 */
	
	//(Supposed) Random function
	function rA(n, x) {
		return (n + (Math.random() * (x - n)))
	}

	var ctx = window.c, //get the canvas context
	s = new(AudioContext), //prepare sound context
	d = 1, ds = -1, //use to create inverted variables
	cW = 1920, //canvas Weight
	cH = cW / 2, //canvas Height
	x = -cH, //first bird position
	wY = z = 0, //wings bird position and angle
	sX = 3, //horizontal bird speed
	sz = .2, //wing & blades of grass angle speed
	wM = 17, //wing Max amplitude
	nB = 15, //birds number
	_BoGrass = [], //blades of grass
	lM = 240, //number of blades of grass
	v = 20; //a point to draw a blade of grass
	//x1 = 18, //x1,y1 is the moving point of wing and x1 = (x2+x3)/2 also 31+5/2
	//y1 = 5, //y1 = (y2+y3)/2 also 5+5/2
	//x4=41,y4=0

	var _Birds = []; //birds array
	_P = [18, 5, 31, 5, 41, 0, 5, 5]; //points to draw birds
	_Birds[0] = _P;

	//Need that lM>nB , remove one "for loop" line
	for (i = 1; i <= lM; i++) {
		//Create differents blades of grass positions
		_BoGrass[i - 1] = {
			x : rA(0, cW), //Random to create differents blades of grass horizontal positions
			o : rA(0, 1.5) //Random to create differents blades of grass curve positions
		};
		if (i <= nB) { //Used to remove one "for loop" line
			cstx = rA(90, cH / 3); //Random to create differents blades of grass vertical positions
			_Birds[i] = [];
			for (var U = 0; U < 8; U++) {
				_Birds[i][U] = _Birds[0][U] + cstx;
			} //Create differents birds positions
		}
		//Crickets Sound generator
		if (i < 3) { //Used to remove one "for loop" line
			setInterval(function () {
				f = [0, 4E3, .2, .3, 12E3, .6, .6, 10E3, .8]//.2,0,.7,
				for (var I = 0; I < 7; I += 3) {
					var o = s.createOscillator(); //Test with http://p.chas.free.fr/demo/jsaudioapi/index.html
					o.frequency.value = f[I + 1]; //3-->8KHz, it's the cricket sound ... they think : http://www.scholarpedia.org/article/Cricket_acoustic_communication
												  //But get a .wav on net where f is a sin between 4-->12KHz
					o.type = 'square'; //But what's the type of oscillation ? https://developer.mozilla.org/fr/docs/Web/API/OscillatorNode/type
					o.connect(s.destination);
					o.start(f[I]); //Start to play crickets sound
					o.stop(s.currentTime + f[I + 2]);//Stop to play in above 2 seconds
				}
			}, i * 2300);
		}
	}

	var fps = 30;
	function drawc() {
		setTimeout(function() {

		x = x + sX; //Change x bird position
		z = z + sz; //Change O wings bird angle
		if (x > cW) { //If bird quit the screen by the right
			x = -cH; //Go to the left ...
			z = 0 //Reset wings bird angle
		}

		for (var i in _Birds) { //= 0; i < nB; i++) {
			g = parseInt(i); //Must convert, you know the cause
			ctx.fillStyle = '#F8' + (g.toString(16)); //Select a color to draw between F80-->F8F //use http://p.chas.free.fr/demo/shorthandcolors/index-h.html
			l = cH / nB; //Cut canvas Height in nB parts
			ctx.fillRect(0, (i) * l, cW, (i + 1) * l); //So draw a gradient effect

			if (i % 2 == 0)
				d = ds * d; //d to have differents wings positions of birds
			wY = d * wM * Math.sin(z); //Sinusoidal function wM-->0-->-wM
			ctx.fillStyle = '#000'; //Select black to draw
			ctx.beginPath(); //Start to draw a bird
			ctx.moveTo(_Birds[i][0] + x, _Birds[i][1] - wY);
			for (var j = 2; j < 9; j += 2) {
				ctx.lineTo(_Birds[i][j] + x, _Birds[i][j + 1]);
			}
			ctx.closePath();
			ctx.fill(); //Finish to draw a bird
		}
		//Grass moving in the wind
		for (var l in _BoGrass) {
			_BoGrass[l].o = 20 * Math.abs(Math.sin(z)); //Sinusoidal function 0-->20
			px = _BoGrass[l].x; //Blade of grass movement
			ctx.beginPath(); //Start to draw a blade of grass
			ctx.moveTo(v + px, cH);
			ctx.quadraticCurveTo(10 + px, 100, v + px + _BoGrass[l].o, 200);
			ctx.stroke(); //Finish to draw a blade of grass
		}

		//requestAnimationFrame(drawc); //Synchronize with the framerate
		drawc();
		}, 1000 / fps);
	}
	drawc(); //There is always a begin