i want ask a extra qustion to confirm my assumption for using Compositor layer right.
Is Oculus Gear vr home app using "Underlay" to Render Ui Panel ?
oculus staff said "we do use overlay in Gear VR home, and the fact is that everything is made by overlay in gear VR home", while gear controller & its white laser can display in front of ui panel shown below.
if gear home using "Overlay" not "Underlay" to render ui panel into cylinder, i do not figure out a valid method to render controller & its laser in front of ui panel, because of "Overlay" blend with eye buffer using Overlay Rt's alpha value. while "Underlay" blend using eye buffer's alpha value.
using Overlay Rt's alpha value for blend and "Overlay" render in front of all things, make the "Overlay" layer can not leak a hole to show the controller.
consider what i assume is right, there must be "Underlay". so gear vr home need "poke a hole" for eye buffer while shader the hole's alpha = 0, which ui panel can blend into eye buffer correctly.
Finally, the render action list for using Compositor layer combine with controller & room shown below:
1. render cinema and some opaque things except gear controller
2. render some transparent things except gear controller laser
3. in simple, clear total eye buffer alpha into 0
4. render controller & laser, write them alpha to corresponding location
4. Underlay ui panel blend with eye buffer, leave eye buffer alpha = 1 not blend
so, Is it right render order for gear vr home ? but the method above can not handle the situation while gear controller behind the UI panel render using "Underlay" because their alpha already = 1.
Or there contian other method to use"Overlay" render ui and make contrller render right? thanks for your time