/**
 * Flade - Flash Dynamics Engine
 * Release 0.4 alpha 
 * CircleSurface class
 * Copyright 2004, 2005 Alec Cove
 * 
 * This file is part of Flade. The Flash Dynamics Engine. 
 *	
 * Flade is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Flade is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Flade; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Flash is a registered trademark of Macromedia
 */


CircleSurface = function(cx, cy, r) {
	
	this.cx = cx;
	this.cy = cy;
	this.r = r;
	
	var drawClipName = "circsurfdrawclip_" + this.depth;
	this.dmc = createEmptyMovieClip (drawClipName, this.depth);
	this.dmc.lineStyle(0, 0x222288, 100);

	CircleSurface.prototype.depth++;
}
CircleSurface.prototype.depth = 9000;


CircleSurface.prototype.paint = function() {
	Graphics.prototype.paintCircle(this.dmc, this.cx, this.cy, this.r);
}


CircleSurface.prototype.resolveWheelCollision = function(w, sysObj) {
	
	var dx = this.cx - w.wp.curr.x;
	var dy = this.cy - w.wp.curr.y;
	var len = Math.sqrt(dx * dx + dy * dy);
	var pen = (w.wr + this.r) - len;
	
	if (pen > 0) {
		dx /= len;
		dy /= len;
		w.wp.curr.x -= dx * pen;
		w.wp.curr.y -= dy * pen;
				
		var wheelNormal = new Vector(-dx, -dy);
		w.resolve(wheelNormal);
	}
}



CircleSurface.prototype.resolveParticleCollision = function(p, sysObj) {

	// TBD: move to constructor, and change constructor args
	var circleCenter = new Vector(this.cx, this.cy);
	var dist = circleCenter.distance(p.curr);
	
	// test if point is within circle
	if (dist <= this.r) {
		
		// get the normal of the surface relative to the location of the point
		var surfaceNormal = (p.curr.minusNew(circleCenter)).normalize();
	
		// project out to surface of circle 
		var surfacePos = circleCenter.plusNew(surfaceNormal.multNew(this.r));
		p.curr = surfacePos;
	}
}