addSubTexture method
Adds a GSubTexture with the given name
to the atlas.
The subTexture
parameter is the GSubTexture to be added.
Throws an exception if the root GTexture of the subTexture
does not
match the atlas GTexture.
Implementation
void addSubTexture(String? name, GSubTexture subTexture) {
if (subTexture.root != _atlasTexture!.root) {
throw 'SubTexture\'s root must be an Atlas Texture.';
}
_subTextures![name] = subTexture;
_subTexturesNames = null;
}