CODEWITHSUNDEEP
c#unity-game-engine
armnotstrong
armnotstrong

Reputation: 9065

how to convert coordinate between cameras with Unity3D

I have two cameras,

why I have two cameras?

because I want some game object in front of the Canvas so that it could move around, maybe could have some particles if it feels happy etc.. So:

  1. I set up the main Camera with mask option UI and make it in charge of all the UI stuff, and to make sure it does not overlap everything I set the canvas mode "Screen-Space Camera"

  2. I set up another camera and make it capture everything else except the UI stuff.

  3. set their depth so that the main Camera with UI will behind the other Camera.

things go well now, I could see the game object before the UI stuff. Cheers!

But in some case I what to convert the UI element to the point in the world space, So that I could generate some gameObject near the UI element and maybe Tween it to move to another UI Element, let's take collecting Gems as an example.

Usually, I could just do that with following code:

  GameObject go  = Instantiate(eff_gem);
  go.transform.position = Camera.main.ScreenToWorldPoint(p1.GetComponent<RectTransform>().position);
  go.transform.DoMove(p2.GetComponent<RectTransform>().position, 1f).OnComplete(()=>{
       Destory(go, 1f);
  });

The main idea is to instantiate a gem near a button and make it fly to the count panel.

But since I make the canvas "Screen Space Camera" instead of "Screen Space Overlay", all the above code will be a mess. furthermore, I think I have to convert the screen point of the canvas element to the world space by the other camera, But I can't even get the actual pixel position of the canvas element by

p1.GetComponent<RectTransform>().position now.

So How Can I do that?

I have made a demo project to demonstrate the issue.

Upvotes: 0

Views: 334

Answers (1)

Lincoln Cheng
Lincoln Cheng

Reputation: 2303

var p1R = p1.GetComponent<RectTransform>();
Vector3 p1WorldPos = p1R.TransformPoint(p1R.rect.center);
//use p1WorldPos in your other camera

Upvotes: 1

Related Questions