Will the glTF support int or uint for custom attribute?

[insar-dev]

Will the glTF support int or uint for custom attribute?

125 (UNSIGNED_INT) is only allowed when the accessor contains indices.

[javagl]

The name _FEATURE_ID_0 suggests that this may be intended for the use in the proposed EXT_mesh_features extension. The proposal carries an implementation note that says

Because glTF accessors do not support UNSIGNED_INT types for 32-bit integers in vertex attributes, FLOAT may be used instead allowing integer feature IDs up to 2²⁴. For smaller ranges of feature IDs, UNSIGNED_BYTE or UNSIGNED_SHORT may be used. As with other vertex attributes, each element of a feature ID accessor must align to 4-byte boundaries.

Regardless of that: No, glTF does not support UNSIGNED_INT for mesh attributes, and most likely never will (except for the case where support for this attribute may be added with a dedicated extension).