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Moving objects by a link point?

by Nick Sabalausky · in Torque Game Builder · 03/22/2005 (6:37 pm) · 5 replies

I know I can get by without it, but it would be nice if it were possible to do something like this:

// Contrived example
$thing.leftEdge = $thing.addLinkPoint("-1 0");
$thing.leftEdge.setPosition("4 7"); // Move $thing so that it's left edge is at (4,7)

Is there a built-in way to do this, or do I have to explicitly subtract the coordinates to get the vector between the points and then offset my "$thing.setPosition()" by that vector?
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Employee Melv May
#1
03/23/2005 (3:21 am)
Nick,

The "addLinkPoint()" does not return an object, it returns a position like "100 200" so you can't call functions from it. That's like doing...
"100 200".setPosition("300 400");
... which makes no sense really.

A later update will allow you to set the pivot-point (point of position/rotation) so you can position your object from arbitrary points on your object if that helps.

- Melv.

Torque Owner Teck Lee Tan
#2
03/23/2005 (7:22 am)
Quote:A later update will allow you to set the pivot-point
Woohoo! :)

Torque 3D Owner Matthew Langley
Torque
#3
03/23/2005 (7:35 am)
You could make a function to

Quote:Is there a built-in way to do this, or do I have to explicitly subtract the coordinates to get the vector between the points and then offset my "$thing.setPosition()" by that vector?

then just simply call this function passing the object and the link point

Torque Owner Nick Sabalausky
#4
03/23/2005 (8:25 am)
Quote:You could make a function to ... then just simply call this function passing the object and the link point
Well, I just wasn't sure if there was already a built-in way to do it. But yea, I've just now gone ahead and written a function for it. The code is a lot simpler than I originally thought it would be (The Torque scripting language is awesome :) ). Here it is for anyone who's interested:

function fxSceneObject2D::setPositionByLinkPoint(%this, %linkPoint, %position)
{
    %offsetVector = vectorSub(%this.getLinkPoint(%linkpoint), %this.getPosition());
    %this.setPosition(vectorSub(%position, %offsetVector));
}

// Sample usage:
$thing.myLinkPoint = $thing.addLinkPoint("-1 -1");
$thing.setPositionByLinkPoint($thing.myLinkPoint, "17 15");

Torque 3D Owner Matthew Langley
Torque
#5
03/23/2005 (8:33 am)
Very cool :)