OES_texture_float doesn't actually define the ability to render to floating point textures. We do happen to support that in ANGLE, but it is not a portable behaviour (and will almost certainly not work on true ES devices).
LUMINANCE_ALPHA textures are also not renderable in ES 2.0 (and are not in ANGLE). May desktop GL implementations made them renderable before RG textures were introduced, but that was more of a silent extension, not a requirement. You should be able to check this via a framebuffer completeness test.
Hope this helps,
On 2010-12-16, at 7:51 AM, Evgeny Demidov wrote: