let n = 0, randomX = [], randomY = [], randomS = [];
var rn;


let tree
let branchLength = 100
let minimumWeight = 0.03
let iteration = 15

function preload() {
  createVRCanvas();
}

function setup() {
  setVRBackgroundColor(200, 200, 200);
  noStroke();

  //calculate random positions for trees
  for(let i=0; i<iteration; ++i) {
    randomX[i] = random(-175, 175);
    randomY[i] = random(-175, 175);
    randomS[i] = random(15, 20);
  }

  angleMode(DEGREES)

  //random seed for each respawn
  rn = random(1,1000)
}

function draw() {
  n = n + deltaTime/30;
  setViewerPosition(0, 10, 350-n);
  
  //respawn
  if(n>=550){
    n=0;
    setup();
  }

  //draw plane
  noStroke();  
  rotateX(90);
  fill(0, 160, 0);
  plane(5000, 5000);
  fill(128, 128, 0);
  rotateX(-90)
  
  //draw trees
  for(let i = 0; i<iteration;i++){
    randomSeed(rn+i)
    translate(randomX[i],0,randomY[i])
    branch(randomS[i]);
    translate(0,-randomS[i],0)
    translate(-randomX[i],0,-randomY[i])
  }
  
}


function branch(len) {
  
  strokeWeight(map(len,10,30,0.5,5))
  stroke(70,40,20)
  
  line(0,0,0,0,len,0)
  
  translate(0,len,0)
  
  if(len > 10 ){
    //stem/branch
    for(var i=0;i<3;i++){
      rotateY(random(100,140));
      
      push();
      
      rotateZ(random(20,50));
      branch(len *0.7);
      
      pop();
    }
  } else {
    //leaf
    var r = 80 + random(-20,20)
    var g = 120+ random(-20,20)
    var b = 40+ random(-20,20)
    
    fill(r,g,b,200);
    noStroke()
    
    translate(5,0,0)
    
    rotateZ(90)
  
    triangle(-5,-5,5,5,-5,5)
  }
  
  
}