Packing is used in a couples places in truetrace
And each emissive triangle is it’s own light source, as the triangle itself is a light

At its core, the bit trails are just a string a 1’s and 0’s that tell me which direction to traverse the tree at any given branch to reach a specific triangle(those triangles are at the “leaves” of the tree)

These bittrails that I talk about here in the origional post are used to traverse the light acceleration structure while gaurenteeing the triangle we will end at in the tree
So I can compute the correct weight quickly for any emissive triangle randomly hit by bouncing rays

The structure makes sampling emissive triangles far better/higher quality for Next Event Estimation
However, rays can also randomly hit an emissive triangle by chance, in which case we need to compute a weight so that NEE still is correct when combined with naive
Another reply incomming

So this is a bit of a specialized case for bitfield
They have a LOT of uses, like bitflag packing(which I use for my materials, I can pack 32 booleans into 1 uint of space)
For this specifically, it’s used for the light acceleration structure I use
Need more space, so this will be several replies…

So actually there were 2 major bugs that were 4+ months old that caused massive amounts of fireflies
First one was I forgot a “- 1” in my tlas bitfield traversal
Second was I was double counting mesh count contribution to the pdf, this ones over a year old

Yoooo what?? I thought opacity micro maps were kinda locked down black box to an extent, or needed dedicated hardware to be faster!

What’s the speed vs a pure bvh like?