Is this code correct?

[z]

On Saturday, 1 April 2023 at 15:32:27 UTC, Dennis wrote:
> On Friday, 31 March 2023 at 13:11:58 UTC, z wrote:
>> I've tried to search before but was only able to find articles 
>> for 3D triangles, and documentation for OpenGL, which i don't 
>> use.
>
> The first function you posted takes a 3D triangle as input, so 
> I assumed you're working in 3D. What are you working on?
>
>> Determines if a triangle is visible.
>
> You haven't defined what 'visible' means for a geometric 
> triangle.

explained to the best of my ability : 
https://d.godbolt.org/z/4a8zPGsGo
the "angle bias" i was trying to explain about is present, when 
`rot = 0` the `mask` is supposed to only have three `true` 
values.(that of the "front" triangle.)

>You haven't defined what 'visible' means for a geometric 
>triangle.

Problem is, all i have is an assembly dump and the data it 
interacts with, both of which are very(very) old.