Add Drag n' Drop support for Sprite3D

[julhe]

Describe the project you are working on

3D Game with lots of 2D sprites.

Describe the problem or limitation you are having in your project

It's cumberstone to create a new Sprite3D each time I want to add a sprite to the 3D scene.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Allow for Drag n' Drop, in the same fashion as for 2D.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

N/A

If this enhancement will not be used often, can it be worked around with a few lines of script?

N/A

Is there a reason why this should be core and not an add-on in the asset library?

N/A

[Mickeon]

One problem with this is that dragging a Texture2D/Material to the viewport allows overriding a Mesh's texture, so the proposed behaviour should be probably accessible with a shortcut.

[julhe]

@Mickeon Yeah, I guess it conflicts with the current behaviour. Maybe it's possible to change the default behaviour with holding the alt key, similiar to how it is done in 2D?

[Mickeon]

One other complication I'm encountering is that scale is a big issue, yeah. The texture may be small, which results into the Sprite3D looking small. A Popup when holding the Alt Key looks to be necessary at this point.

If this... feature is particularly useful, even. Typically, in a 3D environment one may want more granularity: splitting Nodes into scenes, each of them is a Sprite3D, copying and pasting that Scene, instead of the raw Sprite3D...

But the 3D equivalent to that menu could be generally useful for setting those Scenes up fast.

[Calinou]

Moved to discussion, as there is no concrete technical implementation proposed and some questions were not filled in.