[osg-users] Layered rendering with a geometry shader

[Chris Djali]

Hi,

I'm investigating using a geometry shader to render multiple shadow map cascades in one pass in OpenMW. While I've heard conflicting (but mostly negative) accounts of how much additional performance this can bring, I reckon it's likely to help, as OpenMW uses a ridiculous quantity of tiny drawables, causing a ridiculous number of draw calls when RTT passes are used, and there's no easy batching implementation as user/game scripts can add, remove, replace and relocate object with no notice. There are solutions in the works for this, but layered rendering may be low-hanging fruit that can be done in the meantime.

Anyway, onto the problem at hand...

In order to do this, I need to bind a layered depth texture as a render target. When I looked into doing this in OSG, the two threads I found claimed it wasn't possible yet, but as they were from a long time ago, it's possible support has been implemented since them. Can this be done yet? I'd rather not have to spend a long time investigating only to determine that it's still impossible.

Thank you!

Cheers,
Chris

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