One backend's way of writing rows into a texture's existing GPU resource.
resource identifies that resource (undefined = none allocated);
writeRows returns false when the resource is not a shape it can write,
so the caller falls back to three's full upload.
One backend's way of writing rows into a texture's existing GPU resource.
resourceidentifies that resource (undefined = none allocated);writeRowsreturns false when the resource is not a shape it can write, so the caller falls back to three's full upload.