I’m just integrating ARB_vertex_program support into my engine, and I was wondering why the extension, unlike NV_vertex_program, does not support querying the enable state of the generic vertex arrays. All you can do is enable or disable them with glEnable/glDisableVertexAttribArrayARB. But there’s no IsEnabled or something similar. Not that it’s a big deal, but it would be nice to have for reasons of symmetry.
On a similar topic, how ineffecient is it to enable an already enabled array? For example, if I called glEnableVertexAttribArrayARB every frame for an array, even though that particular array is already enabled, would that be a bad idea? I guess it just sets a flag in the driver, but who knows? Does anyone have any experience with this?