code: function( ax, ay,
  								   bx, by,
  								   cx, cy,
  								   px, py ) {
  
  		  var aX, aY, bX, bY;
  		  var cX, cY, apx, apy;
  		  var bpx, bpy, cpx, cpy;
  		  var cCROSSap, bCROSScp, aCROSSbp;
  
  		  aX = cx - bx;  aY = cy - by;
  		  bX = ax - cx;  bY = ay - cy;
  		  cX = bx - ax;  cY = by - ay;
  		  apx= px  -ax;  apy= py - ay;
  		  bpx= px - bx;  bpy= py - by;
  		  cpx= px - cx;  cpy= py - cy;
  
  		  aCROSSbp = aX*bpy - aY*bpx;
  		  cCROSSap = cX*apy - cY*apx;
  		  bCROSScp = bX*cpy - bY*cpx;
  
  		  return ( (aCROSSbp >= 0.0) && (bCROSScp >= 0.0) && (cCROSSap >= 0.0) );
  
  	}
docs: see if p is inside triangle abc