#physics problem

1 messages · Page 1 of 1 (latest)

short hull
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I believe your issue is in your update method.

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Vector3 Xm = new Vector3(Input.GetAxisRaw("Horizontal"), rb.velocity.y, Input.GetAxisRaw("Vertical"));
Vector3.Normalize(Xm);
rb.velocity = transform.TransformDirection(Xm) * speed; /*
wet isle
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Is it the fact it creates a new vector3 every frame?

short hull
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the pertinent problem: Vector3.Normalize doesn't modify the argument

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it returns a new vector

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so that isn't doing anything

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therefore, every frame, your y-velocity gets multiplied by speed

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you could fix that by doing Xm = Vector3.Normalize(Xm);

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however, that would not behave very well

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your vertical velocity would just kinda get stuck at a maximum of speed

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I would suggest computing your X and Z movement separately from your Y movement

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Read input into the X and Z components of a vector, normalize it if it's non-zero (otherwise you'll normalize a zero vector!), and multiply that by speed

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then just copy the old y-velocity over

wet isle
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So basically have two separate Vector3's, one for my X and Z, and one for my Y?

short hull
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Yeah, that'd be one way to do it. I wouldn't even bother making the "vertical" vector tho

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maybe if there was more complex logic going on

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the rigidbody already does gravity for you, and you aren't doing anything else funky with the vertical velocity

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so I'd just compute the XZ vector and then do moveVec.y = rb.velocity.y

wet isle
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So what your saying is instead of using rb.velocity.y, put a 0. Normalize, and then set the value of the Y to rb.velocity.y?

short hull
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Yep.

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So that you don't mangle the vertical velocity

wet isle
short hull
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it would be what you called Xm

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I'll usually have something like

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Vector3 inputVec = new(xInput, 0, yInput);
inputVec = transform.TransformDirection(inputVec);
Vector3 moveVec = inputVec * speed;
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get user input, transform it from local space to world space (to account for rotation), and then compute a movement vector from that

wet isle
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Gotcha

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Uh oh, I just tried what you said and I may have screwed it up by a hair

short hull
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again, Normalize doesn't modify the argument

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it literally can't in this case, because Vector3 is a struct: thus, a value type

wet isle
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So just get rid of it?

short hull
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even if the function changed the values in the argument, it wouldn't affect the original

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no, you need to save the result...

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look up Vector3.Normalize in the unity docs

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look at the return type

wet isle
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Whatever I did, It just worked. Jumping needs a little fixing, but it works nonetheless