Problem Converting GUI to World Coords in Editor

Questions & Answers
1

Hi everyone,

I’m making a type of board game that I wish to design myself in the editor (there are many types of boards). I’m trying to write a level editor to make this easier.

What I want is to be able to select a type of tile from a list and then click in the scene view to make it appear where I clicked (while snapping into a grid).

I have been able to make it put a tile when I click, however it’s putting the tile at an offset (30-40 pixels above where I click). And I can’t seem to figure out why.

My code looks like this (didn’t get the grid part in yet):

if (Event.current.type == EventType.MouseUp)
{
    // load the correct prefab and create an instance of it
    GameObject space = Resources.LoadAssetAtPath(pathString, typeof(GameObject)) as GameObject;
    GameObject spaceInstance = PrefabUtility.InstantiatePrefab(space) as GameObject;
    spaceInstance.name = current;

    // set its position to where we click
    Vector2 mousePos = Event.current.mousePosition;
    mousePos.y = Screen.height - mousePos.y;

    Vector3 position = Camera.current.ScreenToWorldPoint(mousePos);
    position.z = 0;
    spaceInstance.transform.position = position;

    EditorUtility.SetDirty(spaceInstance);
}

I’m currently working around it simply by subtracting an additional 35 from mousePos.y, but there has to be a better fix than that.

3

You should use the Handles and HandleUtility class for anything related to the SceneView. The problem is that Screen.height returns the windows device context height which includes the tab-bar and the header bar.

SceneViewViewport

The green area is the GUI area while the red one is the actual screen buffer. btw: the green one is enclosed by the red area.

The Handles class also let you draw cameras, handles, gui and other things in your own editor window. Just play around a bit. The documentation is your friend. Just switch to “editor classes” and browse the classes :wink:

2

In the editor I have found Screen.height is often inaccurate,
where you have…

mousePos.y = Screen.height - mousePos.y;

Try this instead:

mousePos.y = Camera.current.pixelHeight - mousePos.y;

The camera pixelHeight property should be the real height of the scene view.

Hope this helps

Phill