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Known bug: object/object occlusion bogus in PBR mode
http://sldev.free.fr/forum/viewtopic.php?f=4&t=2529		 Page 1 of 1
Author:  Henri Beauchamp [ 2024-07-01 10:15:12 ]
Post subject:  Known bug: object/object occlusion bogus in PBR mode
As most of you already probably noticed, there is a bug in all PBR viewers sometimes causing objects to fail to render at all, and no amount of workarounds (such as "Refresh visibility of objects" in the Cool VL Viewer) can fix it once it starts happening in a session.

For now, the only solution is to un-tick the "Enable object-object occlusion" check box while in PBR rendering mode (meaning you will loose some fps, in some scenes, sadly): you can do this from the "Preferences" floater, "Graphics" tab, "GPU/GL features" sub-tab.

I am still trying to figure out what got broken in LL's PBR occlusion code, but it might take quite a long time before I can find the bug, or a reliable workaround for it...
Author:  Henri Beauchamp [ 2024-07-09 22:13:12 ]
Post subject:  Re: Known bug: object/object occlusion bogus in PBR mode
OK... So, this got worst with v1.32.2.4, because in the latter, I added a "reset vertex buffer" action after the automatic "refresh object visibility" trick used after login, to work around the slower fps rate sometimes seen just after login... Which allowed me to find the reason for this bug !

LL simply removed entirely the reset vertex buffer feature, since it was incompatible with the occlusion culling in their PBR renderer... Yet, I do need to reset (most) vertex buffers to be able to toggle between the PBR and ALM/forward renderers.

The good news is that I think I found the good compromise, by only skipping the spatial partition vertex buffers reset (which was also clearing the occlusion queries names, etc).

I am currently testing the fix. In the mean time, disable "Object/object occlusion" while in PBR mode...
Author:  Henri Beauchamp [ 2024-07-10 07:38:51 ]
Post subject:  Re: Known bug: object/object occlusion bogus in PBR mode
In fact, the vertex buffer reset removal was an overkill from LL's part: I could keep it and simply solved the occlusion culling breakage by not wiping the occlusion data on VB reset, and properly flagging occlusion groups for rebuild.

Fix implemented for Saturday's release. In the mean time, do keep object/object occlusion off while in PBR rendering mode (yes, it sucks, because it impacts frame rates and VRAM consumption)...

If you build the viewer yourself, you can apply this tiny patch to get things fixed:
Attachment:
repair-pbr-culling-patch.txt [776 Bytes]
Downloaded 68 times
Author:  Henri Beauchamp [ 2024-07-13 08:26:11 ]
Post subject:  Re: Known bug: object/object occlusion bogus in PBR mode
Fixed in v1.32.2.5 (with additions, compared to the patch above, solving disappearing objects on TPs to adjacent sims).
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