Mirroring a 2d point on from another 2d point. | Official Unity Discord | Page 1

lost turret Dec 13, 2021, 5:21 PM

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Hi! im trying to mirror a point on a 2d plan using another point....

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I tried using the angle between the two and the distance, but i cant seem to make it work...

azure sand Dec 13, 2021, 5:22 PM

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https://docs.unity3d.com/ScriptReference/Vector2.Reflect.html

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Should work the same for directions and points

lost turret Dec 13, 2021, 5:23 PM

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it has no explanation on how to use it lol

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azure sand Dec 13, 2021, 5:23 PM

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Reflects a vector off the vector defined by a normal.

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That's exactly how to use it. The normal is like the surface of whatever you're reflecting off of

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So if it's a table top the normal is up

lost turret Dec 13, 2021, 5:24 PM

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so like 90 degrees to both of the points?

azure sand Dec 13, 2021, 5:25 PM

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No. It's going to be coplanar, but that's beside the point

lost turret Dec 13, 2021, 5:25 PM

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so how do i define it?

azure sand Dec 13, 2021, 5:25 PM

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Like I said, the normal is like the direction the surface is pointing. Like a mirror

lost turret Dec 13, 2021, 5:26 PM

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i dont get how do i define the normal?

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and what is the angle?

azure sand Dec 13, 2021, 5:27 PM

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Thinking about this though you might need to do this in local space

lost turret Dec 13, 2021, 5:27 PM

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how do i define a vector with it in genral...

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i do need it in local space

azure sand Dec 13, 2021, 5:28 PM

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Well, you want a mirror a vector across another point right?

lost turret Dec 13, 2021, 5:28 PM

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yes

azure sand Dec 13, 2021, 5:28 PM

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You need to find out what axis you want it mirrored across

lost turret Dec 13, 2021, 5:28 PM

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i got the angle between the two points?

azure sand Dec 13, 2021, 5:29 PM

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No, you don't need that

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Imagine putting up a mirror so the reflection of the point appears where you want it

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It'll be exactly in the middle right?

lost turret Dec 13, 2021, 5:30 PM

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yes

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what now?

azure sand Dec 13, 2021, 5:31 PM

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The direction the surface of the mirror is pointing is the normal

lost turret Dec 13, 2021, 5:32 PM

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ok, but how is it defined?

azure sand Dec 13, 2021, 5:32 PM

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It's a Vector2

lost turret Dec 13, 2021, 5:32 PM

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that i get by doing what though?

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can we vc?

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maybe ill understand better

azure sand Dec 13, 2021, 5:36 PM

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Sorry, can't do that rn

lost turret Dec 13, 2021, 5:36 PM

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ok

azure sand Dec 13, 2021, 5:36 PM

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But it depends on what you want to do with it

lost turret Dec 13, 2021, 5:36 PM

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ok ill show you

azure sand Dec 13, 2021, 5:36 PM

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Vector2.Up or Vector2.Right are both valid

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But collisions also give you normals you could use to bounce like a laser

lost turret Dec 13, 2021, 5:38 PM

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i want to calculate the position of c

azure sand Dec 13, 2021, 5:46 PM

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Ok I think I misunderstood

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Do you know how to get the direction from the ghost to the point?

lost turret Dec 13, 2021, 5:47 PM

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vector2.angle?

azure sand Dec 13, 2021, 5:49 PM

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No
It's endPosition - startPosition

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It'll give you a new Vector2

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Add the result of that to the position in between

lost turret Dec 13, 2021, 5:50 PM

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endPosition being the point C?

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ghost -a

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mid -b

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target -c

azure sand Dec 13, 2021, 5:53 PM

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We're trying to find c

lost turret Dec 13, 2021, 5:53 PM

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yes

azure sand Dec 13, 2021, 5:53 PM

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In this case endPosition is the mid point

lost turret Dec 13, 2021, 5:54 PM

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so, endPosition + (endPosition - startPosition )?

azure sand Dec 13, 2021, 5:55 PM

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For this yes. endPosition - startPosition is a common formula though, so it's good to remember

lost turret Dec 13, 2021, 5:56 PM

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i legit did that allready, but i wrote it with a mistake

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it works

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thank you very much

azure sand Dec 13, 2021, 5:57 PM

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Np

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It's the little things that give us the biggest headaches :p

lost turret Dec 13, 2021, 5:57 PM

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true, i was on that for an hout

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hour

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so simple ....

#Mirroring a 2d point on from another 2d point.