constructor(x, y, links, growChance, branchDir, isRoot=false){

    this.pos = createVector(x,y);

    this.links = links;

    this.id = stems.length;

    this.growChance = growChance;

    this.branchDir = branchDir;

    this.isRoot = isRoot;

    this.alive = true;

    this.restLength = stemLength;

    this.externalPull = createVector(0,0);

    this.flowers = [];

    this.leaves = [];

    for(let i=0; i<this.links.length; i++){

      stems[this.links[i]].links.push(this.id);

    }

    stemcount++;

  }

  drawLinks(){

    if(!this.alive){

      return;

    }

    for(let i=0;i<this.links.length;i++){

      line(this.pos.x, this.pos.y, stems[this.links[i]].pos.x, stems[this.links[i]].pos.y);

    }

  }

  pushPull(){

    let move = createVector(0,0);

    let linkcount = this.links.length + 1;

    if(this.isRoot){

      return;

    }

    for(let i=0;i<this.links.length;i++){

      let p = createVector( stems[this.links[i]].pos.x, stems[this.links[i]].pos.y );

      move.add( p5.Vector.mult( 

        p5.Vector.sub(this.pos, p), // the vector towards the linked node

        (this.restLength / p5.Vector.dist(this.pos, p)) - 1.0 ) // how close the current lengh is to the rest length

      );

    }

    move.div(linkcount*pullstepdiv)

    this.pos.add(move);

    this.pos.add(this.externalPull);

    this.externalPull = createVector(0,0);

    this.pos.add(this.branchDir);

    // this.pos.add(createVector(0,-0.15));

  }

  grow(){

    if(!this.alive){

      return;

    }

    //die if energy is low FIX THIS ITS TOO ROUGH RN

    if(this.links.length == 1 && random() < (stemcount*4 - pEnergy)*0.02 && stemcount>10 && this.leaves.length == 0){

      stemcount--;

      this.alive = false;

      for (var i = 0; i < stems[this.links[0]].links.length; i++) {

          if (stems[this.links[0]].links[i]== this.id) {

              stems[this.links[0]].links.splice(i,1);

          }

      }

      return;

    }

    // grow stem?    

    if(random() < this.growChance * branchingFalloff**(this.links.length-1)) {

      stems.push(new Stem(

        this.pos.x, 

        this.pos.y,

        [this.id],

        growthFalloff * this.growChance,

        createVector( (random() - 0.5) * (this.links.length - 0.9) * horSpread, -1.0 ).setMag(0.5)

      ));

    }

    //or leaf

    else if (random() < leafChance * leavesFalloff**(this.leaves.length-1) && !this.isRoot){

      leaves.push(new Leaf(

        this.id,

        this.branchDir.heading() + (random()-0.5)*PI,

        5

      ));

    }

    //or flower

    // else if (random() < 1 - this.pos.y/height + 0.01*(energy-flowers.length*100)){

    else if (false){

      flowers.push(new Flower(

        this.id,

        this.branchDir.heading() + (random()-0.5)*PI,

        20,

        ceil(12*random())

      ));

      print('flower!')

    }

  }

}