Benoit Freslon's blog » ActionScript

ActionScript: test collision between a circle and a line

admin — Thu, 19 Aug 2010 18:27:45 +0000

Preview:

Download source code: circle_line_collision

Code:

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// Test collision between a circle and a line
// coded by Benoit Freslon
//
// www.benoitfreslon.com

// Copy and paste this function into your code and don't forget to import the Point class.

import flash.geom.Point;

// pP1: (Point) the first point of the line
// pP2: (Point) the second point of the line
// pC: (Point) the point of the circle
// pRay: (Number) the ray of the circle
function lineCircleCollision(pP1:Point,pP2:Point,pC:Point, pRay:Number):Boolean {
var x0:Number = pC.x;
var y0:Number = pC.y;

var x1:Number = pP1.x;
var y1:Number = pP1.y;

var x2:Number = pP2.x;
var y2:Number = pP2.y;

var n:Number = Math.abs((x2-x1)*(y1-y0)-(x1-x0)*(y2-y1));
var d:Number = Math.sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
var dist:Number = n/d;

if(dist > pRay) {return false;}

var d1:Number = Math.sqrt((x0-x1)*(x0-x1)+(y0-y1)*(y0-y1));

if((d1-pRay) > d) {return false;}

var d2:Number = Math.sqrt((x0-x2)*(x0-x2)+(y0-y2)*(y0-y2));

if((d2-pRay) > d) {return false;}

return true;
}

// Now test this function

// 2 points for the line
var pt1:Point = new Point(100,50);
var pt2:Point = new Point(300,400);

// The ray of the circle 30px
var ray:Number = 30;

// Draw the line
this.graphics.lineStyle(1);
this.graphics.moveTo(pt1.x,pt1.y)
this.graphics.lineTo(pt2.x,pt2.y);

// Drag the circle
circle.startDrag(true);

// And test the collision
this.addEventListener(Event.ENTER_FRAME, enterFrame);
var ptC:Point = new Point(circle.x,circle.y);
function enterFrame (pEvt:Event):void {
// Update circle coordinates
ptC.x = circle.x;
ptC.y = circle.y;
if (lineCircleCollision(pt1,pt2, ptC, ray)) {
// Collision ok
circle.alpha = 0.5;
} else {
// No collision
circle.alpha = 1;
}
}

Flash CS5 builds Iphone applications

admin — Tue, 06 Oct 2009 09:58:45 +0000

Flash Professional CS5 will enable you to build applications for iPhone and iPod touch using ActionScript 3. These applications can be delivered to iPhone and iPod touch users through the Apple App Store.*

A public beta of Flash Professional CS5 with prerelease support for building applications for iPhone is planned for later this year. Sign up to be notified when the beta starts.

At MAX 2009, Adobe showed a number of applications and games for iPhone that have been built using a prerelease version of Flash Professional CS5. These applications are available now for you to download from the Apple App Store.

Go to the official article on labs.adobe.com: http://labs.adobe.com/technologies/flashcs5/appsfor_iphone/#divider

New game, new gameplay, Roll and Jump

admin — Thu, 03 Sep 2009 16:47:54 +0000

Roll and Jump is a skill game where the goal is to climb as high as possible by jumping from a rolling circle to another.

Clim and do the highest score as possible.
You can do a wall jump, a double jump or activate slow motion!

The game will be released in few days on the web i hope to bring it on iphone as soon as possible.

Win 80% performance on Flash ActionScript 2 project

admin — Wed, 18 Mar 2009 12:17:51 +0000

If you have lot of AS 2.0 projets like me you should be happy to know that you could win 80% performance on your projets with 4 lines of ActionScript.

First compile your AS 2.0 project with Flash.

Export your swf file in AS 2.0. (eg: your_as2_project.swf)

Then create an AS 3.0 loader with Flash CS3 or better.

Keep the same framerate on your loader. The same dimentions and the same background color. Put those lines into your AS 3.0 loader and replace the swf file with your file name.

var request:URLRequest = new URLRequest("your_as2_project.swf");
var loader:Loader = new Loader();
loader.load(request);
addChild(loader);

Finnaly compile your AS 3 loader.

It’s magic it works perfectly. It’s more smoothly and more faster. Thanks AVM2 ;).

Very important notes :

Delete all your TextField variables on you AS 2.0 file and use instance name. In AS 3.0 AVM2 doesn’t support TextField variables.
You couldn’t send HTML parameters to swf direclty to your AS 2.0 swf. You have to use a LocalConnection in order to send and receive informations between your 2 swf.