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OnCollosion Normal vector

by Phillip O'Shea · in Torque Game Builder · 07/27/2007 (5:09 am) · 2 replies

Hello,

I need to know how the %normal variable in the onCollision function is calculated. I don't have TGB Pro, otherwise I'd be able to find out myself.

Essentially, I have two collision points (from the collision polygon, so they are in local position terms) and I want to calculate their normal vectors, but I need to do it before the onCollision function is called.

Thanks guys,
Phil
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Associate Phillip O'Shea
Violent Tulip

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    Torque 3D Owner Marc Dreamora Schaerer
    Gayasoft
    #1
    07/27/2007 (6:25 am)
    You need to have the collision polygons as well and calculate it up from there. Just points won't return anything.
    *and if you have the polygon, its actually very simple. Just use the direction from one of the points to the next of the 2 points that form the connection on which the collision point is laying, then exchange the components and negate one of the two. which one you need to negate, depends on which side is the "outside" of the polygon and can easily be calculated using a 3rd point on the collision polygon.*

    Associate Phillip O'Shea
    Violent Tulip
    #2
    07/29/2007 (3:00 am)
    Hi Marc,

    I'm not 100% sure that I understood all of that. Do you think you could give me an example?

    Edit: I found out what I needed, it was pretty simple really.

    For those interested, I had two points A = (a1, a2) and B = (b1, b2). I found the line AB by taking A from B and then scaling A to keep it uniform with B. Then divide through by the hypotenuse!

    Thanks,
    Phil