metaball

metaball.js

//make lumpy circles

function makecircle(r){
  return function(x,y){
    return Math.pow(x,2) + Math.pow(y,2) < Math.pow(r,2);
  }
}

function translate(tx, ty, func){
  return function(x,y){
    var xprime = x-tx;
    var yprime = y-ty;

    return func(xprime,yprime);
  }
}




function nothing(){
  return function(x,y){return false};
}

function scale(sx, sy, func){
  return function(x,y){
    return func(x/sx, y/sy);
  }
}

function dist(x,y){
 return Math.pow(Math.pow(x,2)+Math.pow(y,2),0.5);
}

function max(a,b){
  if(a>b){
    return a;
  }else{
    return b;
  }
}

function min(a,b){
  if(a<b){
    return a;
  } else {
    return b;
  }
}

function bulge(cx,cy,stddev,amp,func){
  return function(x,y){
    //distance from point to center
    var dd = (dist(x-cx,y-cy));

    //normal vector from point to center
    var ux = (cx-x)/dd;
    var uy = (cy-y)/dd;
    
    var indraw=amp*(Math.exp(-Math.pow(dd/stddev,2)));
    indraw = min(dd,indraw);

    var xp = x+indraw*ux;
    var yp = y+indraw*uy;

    return func(xp,yp);
  }
}

emit( bulge(151,189,100,60,
        translate(250,250,
         scale(1.6,1.6,
           makecircle(75)
         )
       ) ));