4 ms·
Well if you have more than 2 levels you can always collapse, which is the preferred solution. Just walk the scenegraph, and flatten the matrices. Now you're lef
by jbikker 4y ago
Well if you have more than 2 levels you can always collapse, which is the preferred solution. Just walk the scenegraph, and flatten the matrices. Now you're left with an array of BLASses, each with their final matrix.
RTX has hardware support for this flattened structure only; OptiX will become significantly slower if you force it to have more levels.
- dahart 4y agoYes, very true. Or at least you can usually collapse. Memory is the issue, and collapsing multilevel doesn’t always fit. There is some cost in the current hardware to multi-level traversal, that’s true. But still top & bottom terminology isn’t future-proof, doesn’t translate to CPU, and we might not be limited to 2-level GPU traversal forever. More to the point perhaps is that “top” and “bottom” aren’t words that describe the function. It’d be better to have terms that say what it does rather than where to find it, right? Full disclosure, I work on OptiX. (But to be clear I literally have no idea if/when we might see multilevel traversal in hardware. I just happen to be in favor of seeing it someday, and if/when it does, TLAS and BLAS will become more awkward or get replaced.)