jbikker / bvh_article Goto Github PK

Thanks for your great blog posts, I was just trying to play around with the code a bit this evening.

Immediately had troubles to get this to compile in a fresh installation of VS2022. Namely the DEFINE_ENUM_FLAG_OPERATORS from winnt.h seems missing in the win_tiny.h nowadays. Including the bigger windows.h again and commenting the tiny header works again:

#include "windows.h"
// #include "lib/win_tiny.h" // windows.h replacement for faster builds

I'm on win11 with a fairly recent sdk version: 10.0.22621.0 that I just downloaded. Thought I'll leave a quick note here before others spend hours on figuring out what was missing.

Cheers,
Thomas

Maybe add a default bounds initialization after this line to use the bvhNode[0] bounding box. If SetTransform() is not called on BLAS, the TLAS intersection code will most probably crash.

Hi, I loved your tutorials on BVH. I was saving them for reference. And it appears that the site is not inaccessible anymore: https://jacco.ompf2.com/2022/04/13/how-to-build-a-bvh-part-1-basics/
Getting 403 Forbidden.

Could be a temporary glitch

Hi, I am a little confused about the way to calculate orientation calculation.
in chapter2:
https://github.com/jbikker/bvh_article/blob/89bf112b7ca8c277ac0a311119aa2e29d5ee41f1/faster.cpp#L277C1-L279C57

ray.O = float3( -1.5f, -0.2f, -2.5f );
float3 pixelPos = ray.O + p0 + (p1 - p0) * ((x + u) / (float)SCRWIDTH) + (p2 - p0) * ((y + v) / (float)SCRHEIGHT);
ray.D = normalize( pixelPos - ray.O ), ray.t = 1e30f;

Why need to add ray.O for pixelPos, and minus the ray.O to calculate ray,D. It seems the rays are emitted from (0,0,0), but the ray origin point is still ( -1.5f, -0.2f, -2.5f )

and in chapter1:
In chapter1:
https://github.com/jbikker/bvh_article/blob/89bf112b7ca8c277ac0a311119aa2e29d5ee41f1/basics.cpp#L182C1-L184C41

float3 pixelPos = p0 + (p1 - p0) * (x / (float)SCRWIDTH) + (p2 - p0) * (y / (float)SCRHEIGHT);
ray.D = normalize( pixelPos - ray.O );

there is different calculation for pixelPos (no ray.O added)