Comments on: Throw a ball with a sling physics Flash tutorial

By: This_Guy_is_a_Newbie_in_Flash

This_Guy_is_a_Newbie_in_Flash — Wed, 12 Sep 2007 02:02:05 +0000

thank u very much

btw how can u make it launch when u let go of the
mouse button

again THANK U

By: Frederik J

Frederik J — Sun, 19 Aug 2007 08:02:07 +0000

Yo need to go to your library. Right click on the slings, and press linkage. The you enable “Export for Actionscript”. Make sure you do it at both of them.

By: cod

cod — Sat, 18 Aug 2007 13:04:20 +0000

im having some problems please help me :D
in the first script 1.
attachMovie(“sling”, “sling_1″, _root.getNextHighestDepth(), {_x:20, _y:200});
2.
attachMovie(“sling”, “sling_2″, _root.getNextHighestDepth(), {_x:480, _y:200});
3.
attachMovie(“ball”, “ball”, _root.getNextHighestDepth(), {_x:250, _y:100});
4.
_root.createEmptyMovieClip(“elastic”, _root.getNextHighestDepth());
5.
ball.onPress = function() {
6.
startDrag(this);
7.
};
8.
ball.onRelease = function() {
9.
stopDrag();
10.
};

its not working there is supposed to be 2 slings right but there is nothing but one and when i check the script it says script has no errors

please help me im a newbie to flashbut i know the basics

By: Throw a ball with a sling physics Flash tutorial: Part 2 by Kevin Ward at Emanuele Feronato

Thu, 16 Aug 2007 08:40:12 +0000

[...] Only 2 days. That’s how much time Kevin Ward needed to solve and publish the solution of the problem posted in Throw a ball with a sling physics Flash tutorial. [...]

By: Izy

Izy — Wed, 15 Aug 2007 15:55:30 +0000

It looks like it doesn’t print the plus sign. I guess I’ll have it to e-mail you.

By: Izy

Izy — Wed, 15 Aug 2007 13:17:00 +0000

This one’s really cool.

I think I have it figured out.

var ball:MovieClip = _root.attachMovie(“ball”, “ball”, 2, {_x:275, _y:100});
var elastic:MovieClip = _root.createEmptyMovieClip(“elastic”, 1);
var point1:MovieClip = _root.attachMovie(“sling”, “point1″, 3, {_x:100, _y:200});
var point2:MovieClip = _root.attachMovie(“sling”, “point2″, 4, {_x:450, _y:200});

var gravity = 0.1;

var angle1:Number = 0;

var angle2:Number = 0;

var radius:Number = 13.0; // Or whatever half the width of your ball is.

var released:Boolean = true;

var forced:Boolean = false;

var acc:Object = {x:0,y:0};
var vel:Object = {x:0,y:0};

_root.onMouseDown = function() {

ball._x = _root._xmouse;
ball._y = _root._ymouse;
ball.startDrag();
_root.released = false;
vel.x = 0;
vel.y = 0;
}

_root.onMouseUp = function() {

ball.stopDrag();
_root.released = true;

}

ball.onPress = function() {

ball.startDrag();
_root.released = false;
vel.x = 0;
vel.y = 0;
}

ball.onRelease = function() {

ball.stopDrag();
_root.released = true;

}

_root.onEnterFrame = function() {

elastic.clear();
elastic.lineStyle(5, 0×00EE00);

if (released) {

ball._x = vel.x;
ball._y = vel.y;

}

if (ball._y >= 187) {

forced = true;

var x1:Number = ball._x-point1._x;
var y1:Number = ball._y-point1._y;

var x2:Number = point2._x-ball._x;
var y2:Number = point2._y-ball._y;

var distance1:Number = Math.sqrt(x1*x1 y1*y1);
var distance2:Number = Math.sqrt(x2*x2 y2*y2);

_root.angle1 = Math.atan2(y1,x1);
_root.angle2 = Math.atan2(y2,x2);

var xOffset:Number = Math.cos(angle1 Math.PI/2)*radius;
var yOffset:Number = Math.sin(angle1 Math.PI/2)*radius;

var xOffset2:Number = Math.cos(angle2 Math.PI/2)*radius;
var yOffset2:Number = Math.sin(angle2 Math.PI/2)*radius;

elastic.moveTo(point1._x, point1._y);
elastic.lineTo(ball._x xOffset, ball._y yOffset);

elastic.moveTo(point2._x, point2._y);
elastic.lineTo(ball._x xOffset2, ball._y yOffset2);

}
else {

forced = false;
elastic.moveTo(point1._x, point1._y);
elastic.lineTo(point2._x, point2._y);

}
acc.x = 0;
acc.y = 0;
acc.y = gravity;

if (released && forced) {

acc.x = distance1*Math.sin(angle2)/1000;
acc.y = -distance1*Math.cos(angle1)/1000;

acc.x = distance2*Math.sin(angle1)/1000;
acc.y = -distance2*Math.cos(angle2)/1000;

}

if (released) {

vel.x = acc.x;
vel.y = acc.y;

}

By: squareCircleZ » More game math

squareCircleZ » More game math — Wed, 15 Aug 2007 02:02:02 +0000

[...] One guy has started on his competition entry entitled Throw a ball with a sling. The article includes a tutorial on how he is incorporating mathematics into his game. [...]

By: Emanuele Feronato

Emanuele Feronato — Tue, 14 Aug 2007 15:55:00 +0000

Fixed

Thank you.

By: Dean

Dean — Tue, 14 Aug 2007 13:34:53 +0000

The download link is broken.

By: Adam Owen

Adam Owen — Mon, 13 Aug 2007 15:27:28 +0000

Another awesome tutorial!

I’ve always wondered how this was done after playing the slingstar game on teagames. Their rope bends round the ball but I think your solution looks fine as it is.

Looking forward to seeing how to fling the ball!

Thanks!