2D touch - Why is this movement so jittery?

Question

So I've been struggling for years on how to get an object to move relative to touch delta horizontally in a smooth way, and my best attempt so far has been this:

 if (touch.phase == TouchPhase.Moved)
            transform.Translate(new Vector3(((touch.deltaPosition.x/screen.x) * velocityConstant * Time.deltaTime), 0, 0));

What I've done here: the ratio of the deltaPosition over screen.x pixel count is to normalize deltaPosition across screen sizes, and velocityConstant is a multiplier to move the object further than the actual movement.

Nonetheless, it is jittery, unpredictable and very, very inconsistent. All in all it doesn't behave like it should.
All I need is a movement relative to finger slide that moves further than the actual touch slide (hence why I say it's "relative" and not the exact length).

Any help is appreciated.

Answer 1

Best Answer

Answer by Raimi · Mar 08, 2018 at 05:21 AM

When you use a multiplier on any movement it will cause some jitteryness. The bigger the multiplier, the bigger the jitteryness. This is happens because the object is jumping by the multiplier amount each frame.e.g if the multiplier is three, it will move by 3*time.deltatime each frame, so if its 10 you can imagine whats happening.

Also, instead of using translate, modify the transform directly or use vector3.lerp.

hope it helps

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Davidesq · Mar 08, 2018 at 07:06 PM 0

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Great info, I'll change it up and see how it behaves. Thanks

Davidesq · Mar 25, 2018 at 08:14 PM 0

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Late response: set it to directly change the transform via this:

 transform.position = new Vector3(startPos.x + ((touch.deltaPosition.x / screen.x)*velocityConstant*Time.deltaTime), startPos.y, 0);

It now moves butter smooth, thanks!

2D touch - Why is this movement so jittery?

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