// script:  js
W=240;H=136;SZ=W*H;MW=W/2;MH=H/2;
PALETTE=0x3fc0;SCREEN=0x0000;VOFFSET=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)];};
/* Finkel's Prelude:

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

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

h=0
function make_pal(){
 f=fft(5)*5
 f=lin(0,1,1,0.5,f,true)
 r=lin(-1,1,.8,3,sin(h))*f
 g=lin(-1,1,.8,3,sin(h+tau/3))*f
 b=lin(-1,1,.8,3,sin(h+tau/3*2))*f
 range(16).flatMap(i=>{
  x=i/15
  return[
   255*pow(x,r),
   255*pow(x,g),
   255*pow(x,b),
  ]
 }).forEach((p,i)=>{
  poke(PALETTE+i,p)
 })
 h+=0.01
}

class DP{
 constructor(){
  this.th1=0.1
  this.th2=-0.1
  this.dth1=0
  this.dth2=0
  this.m1=uf(8,13)
  this.m2=uf(5,10)
  this.l1=uf(0.8,1.2)
  this.l2=2-this.l1
 }
 step(dt){
	 let th1=this.th1
  let th2=this.th2
  let dth1s=this.dth1*this.dth1
  let dth2s=this.dth2*this.dth2
  let m1=this.m1
  let m2=this.m2
  let l1=this.l1
  let l2=this.l2
  let g=-10

  //sorry about this :)
  let den=2*m1+m2-m2*cos(2*th1-2*th2)

  var ddth1=-g*(2*m1+m2)*sin(th1)-m2*g*sin(th1-2*th2)-2*sin(th1-th2)*m2*(dth2s*l2+dth1s*l1*cos(th1-th2))
  ddth1/=l1*den

  var ddth2=2*sin(th1-th2)*(dth1s*l1*(m1+m2)+g*(m1+m2)*cos(th1)+dth2s*l2*m2*cos(th1-th2))
  ddth2/=l2*den

  this.th1+=this.dth1*dt
  this.th2+=this.dth2*dt
  this.dth1+=ddth1*dt-this.dth1*0.01*dt
  this.dth2+=ddth2*dt-this.dth2*0.1*dt
 }
}

class P{
 constructor(x,y,vx,vy,h){
  this.x=x
  this.y=y
  this.vx=vx
  this.vy=vy
  this.h=h
  this.ax=x
  this.ay=y
 }
 step(dt){
  var distort=lin(300,0,0,1,this.h)
  //distort=pow(distort,2)
  //distort/=3
  distort*=fft(5)*20

  this.x+=this.vx*dt
  this.y+=this.vy*dt
  this.vx*=0.99//+uf(-1,1)*distort
  this.vy*=0.99//+uf(-1,1)*distort
  this.h--
  this.ax=this.x+uf(-1,1)*distort
  this.ay=this.y+uf(-1,1)*distort
 }
}

function BOOT(){
cls(0)
make_pal()
}

dp=new DP()
ps=[]
px=0
py=0
grace=0
function TIC(){
grace++
 if (grace > 3000){
  grace=0
  ps=[]
  dp=new DP()
 }
	vbank(1)
	cls(0)
 dp.step(0.01)
	s=30
 x0=MW
 y0=MH-15
 x1=x0+sin(dp.th1)*s*dp.l1
 y1=y0-cos(dp.th1)*s*dp.l1
 line(x0,y0,x1,y1,12)
 x2=x1+sin(dp.th2)*s*dp.l2
 y2=y1-cos(dp.th2)*s*dp.l2
 line(x2,y2,x1,y1,12)
 if (grace >5){
	 ps.push(new P(x2,y2,x2-px,y2-py,300))
 }
 px=x2
 py=y2
 vbank(0)
 ps=ps.filter(p=>p.h>0)
 if(!ps.length){
  return
 }

 ppx=ps[0].x
 ppy=ps[0].y
 ps.forEach(p=>{
  p.step(0.3)
  line(ppx,ppy,p.ax,p.ay,15)
  ppx=p.x
  ppy=p.y
 })

 f=fft(5)*3
 pr=lin(0,1,1,0.99,f,true)
 for(i=0;i<SZ;i++){
  v=peek4(i)
  if(v>10 && rnd() >0.5){
   poke4(i,v-1)
  }
  else if(v>0 && rnd() > 0.9){
   poke4(i,v-1)
  }
  else if (v>4 && v<8 && rnd()>pr){
   spoke(i,15)
   spoke(i+1,15)
   spoke(i-1,15)
   spoke(i+W,15)
   spoke(i-W,15)

  }
 }
 make_pal()

}

function spoke(i,v){
 if (i>=0 && i<SZ){
  poke4(i,v)
 }
}