This imports a collection of textures from a PNG image into an [AtlasTexture] or 2D [ArrayMesh]. This can be used to save memory when importing 2D animations from spritesheets. Texture atlases are only supported in 2D rendering, not 3D. See also [ResourceImporterTexture] and [ResourceImporterLayeredTexture].
[b]Note:[/b] [ResourceImporterTextureAtlas] does not handle importing [TileSetAtlasSource], which is created using the [TileSet] editor instead.
If [code]true[/code], discards empty areas from the atlas. This only affects final sprite positioning, not storage. See also [member trim_alpha_border_from_region].
[b]Note:[/b] Only effective if [member import_mode] is [b]Region[/b].
[b]Region:[/b] Imports the atlas in an [AtlasTexture] resource, which is rendered as a rectangle. This is fast to render, but transparent areas still have to be rendered if they can't be trimmed effectively by [member trim_alpha_border_from_region]. This can reduce performance when rendering large sprites on screen.
[b]Mesh:[/b] Imports the atlas as an [ArrayMesh] resource, keeping the original bitmap visible (but rendered as a polygon). This can be used to reduce fill rate when rendering large transparent sprites, at the cost of slower rendering if there are little to no transparent areas in the sprite.
If [code]true[/code], trims the region to exclude fully transparent pixels using a clipping rectangle (which is never rotated). This can be used to save memory. See also [member crop_to_region].
