Exey Panteleev

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Papervision3d 2.0 Using Bezier for Collision Detection

Bezier is package for drawing third-order curves. It can: finding intersection of objects (Bezier, Line), calculating normals, finding shortest way, collisions and their angles, movement point to smooth curve.

Drag points to change curve:

This example based on bezier Demo #8. Just small modification:

private function redraw ():void {
	<...>
	segmentCenters = new Array();
	var segmentsNum:uint = 10
	var times:Array = bezier.getTimesSequence(20)
	for (var i:int = 1; i < times.length; i++) {
		var p1:Point = bezier.getPoint(times[i - 1]);
		var p2:Point = bezier.getPoint(times[i]);
		drawSegment2D(p1, p2)
	}
	drawSegment2D(bezier.getPoint(times[i - 1]), bezier.end)
}

private function drawSegment2D(p1:Point, p2:Point):void {
	var dx:Number = p2.x - p1.x
	var dy:Number = p2.y - p1.y
	//calculate rotation
	var angle:Number = Math.atan2(dy, dx) * Number3D.toDEGREES
	//calculate width of segment
	var distance:Number = Math.sqrt(dx * dx + dy * dy)
	//and center position
	var cx:int = p1.x + dx/2
	var cy:int = p1.y + dy / 2
	segmentCenters.push(new Segment2D(new Point(cx, cy), distance, angle));
}

And create planes from each segment:

var seg:Segment2D = bezierView.segmentCenters[i]
var plane:Plane = new Plane(new MaterialObject3D(), seg.length * propMult * 0.9, 100, 0, 0);
//create extruded plane (Extruder class by J-roen http://www.j-roen.net/papervision/2008/06/12/tutorial-7-vertexes/)
var depth:Number = 10; 
var fMat:MaterialObject3D = new ColorMaterial(0xfffcdf);
var sMat:ColorMaterial = new ColorMaterial(0xbfbca2);
var mList:MaterialsList = new MaterialsList( { front: fMat, back: fMat, side: sMat } );
var p1:Point = new Point(plane.geometry.vertices[0].x, plane.geometry.vertices[0].y)
var p2:Point = new Point(plane.geometry.vertices[1].x, plane.geometry.vertices[1].y)
var p3:Point = new Point(plane.geometry.vertices[2].x, plane.geometry.vertices[2].y)
var p4:Point = new Point(plane.geometry.vertices[3].x, plane.geometry.vertices[3].y)
var extrudedPlane:DisplayObject3D = new Extruder( mList, [p1, p2, p4, p3], depth )
//add our extrudedPlane for scene
extrudedPlane.rotationY = -seg.angle
extrudedPlane.x = seg.center.x
extrudedPlane.z = seg.center.y
scene.addChild(extrudedPlane)

I'm also use here new QuadrantRenderEngine because with ViewportLayers when rotating camera happens overlaps. Quaternion rotating for rolling ball from Dragging in 3D - The Right Way.

Get Full Source

21.10.2008. 03:24

Comments

dVyper 21.10.2008. 15:16

Nice example.

I've noticed some weird behaviour but I'm not sure if it's Firefox 3 or not. If I click on the link to the example it creates a new tab and everything works fine. If I then leave the tab open and browser other websites, after about 10 minutes the example slows down quite a lot. It speeds up again though it I rotate the view.

Also, the memory usage does increase slowly over time. I've had it open for about 20 minutes now and its at 30MB.

Exey 21.10.2008. 22:27

Memory leak because materials of planes not destroying completely

To fix it, I added destroy function from http://www.nabble.com/memory-leak-while-using-Cube-and-MovieMaterial-td19574050.html in Main.as(not in Displayobject3D.as)

But in IE Garbage Collector work better than in FF

Flashbookmarks 08.11.2008. 13:11

Yet a other wonderfull example, as ever :)

Exey: join #papervision3d at irc server freenode server to talk to other pv3d'ers and Andy :)
Or webchat with http://pv3dchat.flashbookmarks.com/

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