Created attachment 229709 [details]
The attached patch performs these 2 actions:
1. sets ISPC to ON (which is also a default value for it)
2. adds the BACKFACE_CULLING option with OFF as default (which is also a default value for it)
Both options are restored to their default values.
This is needed for OSPray, an important raytracing library. which explicitly requires these two Embree options to be at their default values in order to build.
(In reply to Yuri Victorovich from comment #0)
> 1. sets ISPC to ON (which is also a default value for it)
I'm generally not against it, you had actually asked for this in bug #214577 back in 2017 and so I did, but later something got broken and was never fixed until rene@ disabled this option in 2019. Last time I've checked it's okay now and doesn't break the build.
> 2. adds the BACKFACE_CULLING option with OFF as default (which is also a
> default value for it)
Shane asked me to enable EMBREE_BACKFACE_CULLING and EMBREE_RAY_MASK in bug #244190 because Blender expects ray mask to be enabled and while it doesn't currently expect backface culling to be on, it is a common feature used in 3D graphics.
Shane, can you clarify on whether we can disable BACKFACE_CULLING like Yuri's asking, or doing so would break other programs?