// script:  js
W=240;H=136;SZ=W*H;MW=W/2;MH=H/2;
PALETTE=0x3fc0;SCREEN=0x0000;HOFFSET=0x3ff9;abs=Math.abs;floor=Math.floor;max=Math.max;min=Math.min;sin=Math.sin;cos=Math.cos;rnd=Math.random;pow=Math.pow;sqrt=Math.sqrt;pi=Math.PI;tau=pi*2;function lerp(a,b,t){return a+(b-a)*t};function lin(sx,ex,sy,ey,t,cl=false){if (cl) {t=clamp(sx,ex,t);};return lerp(sy,ey,(t-sx)/(ex-sx))};function uf(a,b){return lerp(a,b,rnd())};function ri(mn,mx){return mn+floor(rnd()*(mx-mn+1))};function clamp(mn,mx,t){return max(min(mx,t),mn)};function ss(x){x=clamp(0,1,x);return x*x*(3.0-2.0*x)};function range(n){return Array.from(Array(n)).map((_,i)=>i)};function hsv2rgb(h,s,v){var h=(h%360); if (h<0){h=(h+360)%360;} let c=v*s; let x=c*(1-abs(((h/60)%2)-1)); let m=v-c; let [r,g,b]=[0,0,0]; if (h<60){[r,g]=[c,x];} else if (h<120){[r,g]=[x,c];} else if (h<180){[g,b]=[c,x];} else if (h<240){[g,b]=[x,c];} else if (h<300){[r,b]=[x,c];} else {[r,b]=[c,x];} return [r,g,b].map((x)=>(x+m)*255|0);};function pick(...vs){return vs[ri(0,vs.length-1)];};function hash(i){var s=floor(i);/*var s=i*747796405+2891336453;*/var w=((s>>((s>>28)+4))^s)*277803737;return (w>>22)^w;};
function viz_track(s=20,cl=false){vbank(1);if(cl){cls();};pix(0,0,11);pix(s,0,11);line(0,1,s*2,1,0);line(0,2,s*2,2,0);pix(le*s,1,12);pix(he*s,2,13);vbank(0);}
he=0
le=0
/* Finkel's Prelude:

min,max,abs,floor,pow,sin,cos,rnd
pi,tau,sqrt,hash

lerp,lin,uf,ri,clamp,ss,range,hsv2rgb
pick
*/

function track(){
 damp=clamp(0,1,time()/1000)
 le=max(le,fft(2,4)*0.8*damp)
 le*=0.9
 le=max(0,le-0.3)
 he=max(he,fft(200,250)*1.5*damp)
 he*=0.85
}

function BOOT(){
cls(0)
}
buf=Array(SZ)
function TIC(){
 t=time()/1000
	track()
	vbank(0)
	s=lin(-1,1,5,9,sin(t+le*rnd()*5))
	cstack(0,0,s)
	if(he>0.7){
	 l=floor(uf(2000,SZ/2))
		st=uf(0,SZ-l)
		for(i=st;i<st+l;i++){
		 poke4(i,rnd()*16)
		}
	}
	vbank(1)
	r=le*30*rnd()
	th=t+20*he
	x=r*sin(th)
	y=r*cos(th)
	s=lin(-1,1,5,8,cos(t+he*4))
	cstack(x,y,s)

	vbank(1)
	for(i=0;i<SZ;i++){
	 buf[i]=peek4(i)
		poke4(i,0)
	}
	vbank(0)
	for(i=0;i<SZ;i++){
	 v1=buf[i]
		v0=peek4(i)
		v=v1*v0
		if(rnd()>0.002){
		poke4(i,v)
		}
	}
	c=lin(0,1,0,2,le)
	for(i=0;i<floor(c);i++){
	 l=floor(uf(500,1500))
		memcpy(
		floor(uf(0,(SZ-l)/2)),
		floor(uf(0,(SZ-l)/2)),
		l/2)
	}
	make_pal()
	viz_track(10,false)
}

function cstack(ox,oy,s){
 c=20
 for(i=0;i<c;i++){
  r=s*(c-i)+((i%2)-0.5)*lin(0,1,-5,8,le)+uf(-1,1)*(he*4+0.5)
  var x=MW+ox
  var y=MH+oy
  circ(x,y,r,(i/2)*(i%2))
 }
}

function make_pal(){
	t=time()/3
	a=he>1.1
	a=a?pick(true,false):false
 range(16).flatMap(i=>{
  if(i==0){
	  return hsv2rgb(t,1,0.2)
  }
  off=0
  if(le>0.6){
   off=pick(0,0,0,180)
  }
  x=i/15
  return hsv2rgb(
   t+rnd()*200+off,
   lerp(0.3,1,x),
   1,
  )
 }).forEach((c,i)=>{
  poke(PALETTE+i,a?255-c:c)
 })
}

function BDR(){
 if(rnd()>lin(0,1,1,0.9,he,true)){
	 make_pal()
 }
 if(rnd()>lin(0,1,1,0.97,le,true)){
	 poke(HOFFSET,uf(-1,1)*he*15)
 }
}