Irrlicht Engine

I´m rendering the scene depth to a RTT using the standard shader method to get a greyscale of the depth.

If I use it rendering to the standard frame buffer it works perfectly.

But if I render it to a RTT then I see this sort of moiré pattern, a splattering of pixels that have a very high depth level that move together as I spin the view or model.

I´ve spent hours going through everything but can´t find why the same shader used on an RTT causes this artefact.

Is this a known issue?

did u create a 32 bit float texture for the RTT and pass the data has float? if not u'll lose depth resolution since only int's will get stored on the texture.

Yes exactly, that worked well!