Jacco Bikker 🎦

A four-pane comparison of different formulas for greyscale conversion. Top row: Linear sRGB (the correct way to do it), Gamma sRGB (the somewhat wrong "luma" formula). Bottom row: CIELAB L* (a high quality option), and the new alternative gamma-space version. Careful inspection shows the "Gamma sRGB" case is slightly dimmer at points than the others.

A quote from “Principles of Digital Image Processing” by Wilhelm Burger and Mark J. Burge. It shows weights that are a better fit for gamma-space greyscale conversion.

New article on my site: Better sRGB to greyscale conversion

The commonly used greyscale formula is slightly off when computed in gamma space but can it be fixed?

📜 30fps.net/pages/better...

Graphics Programming weekly - Issue 410 - September 28th, 2025 www.jendrikillner.com/post/graphic...

Have you considered using tinybvh for your ray tracing needs? It's easy to integrate and very fast.

GitHub - nvpro-samples/vk_raytracing_tutorial_KHR at v2 Ray tracing examples and tutorials using VK_KHR_ray_tracing - GitHub - nvpro-samples/vk_raytracing_tutorial_KHR at v2

Vulkan Ray Tracing Tutorial V2.0 Released

Complete rewrite with Vulkan 1.4 support, VMA, Slang. Step-by-step tutorial from raster to ray tracing.
15+ specialized tutorials.
Get started: github.com/nvpro-sample...
#Vulkan #RayTracing #GraphicsProgramming

I always feel a bit dishonest when I click 'not now' when I want to say 'not ever' but the option is unavailable.

Stumbled upon this by accident:
SideFX Houdini 21.0 is using TinyBVH.
www.sidefx.com/docs/houdini...
www.sidefx.com/docs/hdk/_c_...
Not sure what it is used for precisely, but it's pretty cool nevertheless!

Graphics Programming weekly - Issue 409 - September 21st, 2025 www.jendrikillner.com/post/graphic...

Just stumbled upon this ancient PcPersective article on real-time ray tracing.. In 2008. :)
pcper.com/2008/06/ray-...
It details the story of nine students (Karim, Wussie, Rick, Jan, Rutger, Trevor, Mathijs, Roel, Wilco) who worked in various roles on CPU-ray traced games using the Arauna engine.

Graphics Programming weekly - Issue 408 - September 14th, 2025 www.jendrikillner.com/post/graphic...

TinyBVH 1.6.7 is now available on the main branch. Changes:
* TinyBVH now only needs C++11 (tiny_ocl.h needs C++17)
* Full-sweep SAH builder is now threaded
* Fix for crash in BuildAVX
Still zero dependencies. :)
And: The repo reached 1k stars!
Link: github.com/jbikker/tiny...

Shadertoy

in the spirit of sharing, my improvised (aka mess) shader: www.shadertoy.com/view/3fSyWG . only 'new' thing I tried was doing aa/bloom by using a cauchy distribution on the ray jitter, its a sharp but long tailed distribution. gives a pleasing analog glow, still all 1 pass, no rendertargets or blurs

Looks like Steam's store is dead, everyone trying to buy Silksong I suppose? ;)

"Compute"
vec3 p;
for(float i,z,f;i++<4e1;z+=f=.003+abs(length(p.xy)+dot(cos(p),sin(p/.6).yzx)-5.)/7.,o.grb+=(1.5-p/z)/f)
for(p=z*(FC.rgb*2.-r.xyy)/r.y,p.z-=t,f=1.;f++<6.;p+=sin(round(p*6.)/6.*f-t*.5)/f);
o=tanh(o/3e3);

Thanks for the suggestions. The few C++17 / C++20 features definitely are not worth it (although I do like the static inlines..), so I fixed it. This is also reflected in the README. The update is 1.6.7, in the dev branch.

GitHub - jbikker/tinybvh: Single-header dependency-free BVH construction and traversal library. Single-header dependency-free BVH construction and traversal library. - jbikker/tinybvh

TinyBVH 1.6.6 is out on main. Changes:
* Improved speed of FullSweep (thanks Julian)
* Reverted JobSystem to basic threading because of instabilities
* Wave_tracer now uses TinyBVH!
* Fixed speedtest of GPU BVH
Because of the threading issue: Please upgrade to 1.6.6 asap.
github.com/jbikker/tiny...

wave_tracer 0.1 released
wavetracer.dev

wave_tracer combines path tracing and wave optics in a novel way, for practical general-purpose wave simulations across a variety of EM modalities and applications.

GPU utilisation and performance improvements Drill deep into a GPU’s architecture and at its heart you will find a large number of SIMD units whose purpose is to read data, perform some vector or scalar ALU (VALU or SALU) operation on i…

New blog post discussing a few approaches to bottleneck reduction and GPU utilisation and performance increase interplayoflight.wordpress.com/2025/08/29/g...

It's happening again! Do check the line-up, it's awesome!

GitHub - jbikker/tinybvh: Single-header dependency-free BVH construction and traversal library. Single-header dependency-free BVH construction and traversal library. - jbikker/tinybvh

Link: github.com/jbikker/tiny...
Also worth noting:
TinyBVH is rapidly approaching 1000 stars.
Currently: 990 stars, 61 forks, 29 contributors.
Thanks for the support!

TinyBVH was just updated to 1.6.5 on the main branch. Changes:
- Eliminated -Wall warnings (issue #217)
- Improved use of JobSystem (#221)
- Opacity Micromaps support general N (#218)
- Faster full-sweep BVH (#222)
- glm can now actually be used (#215)
Thanks to all contributors and issue reporters!

NVIDIA's new hair tech seems a bit weird. It accelerates "linear swept spheres", and it looks "smooth from a distance". Anything does, NVIDIA. But, why didn't you implement the commonly used "Phantom Ray-Hair Intersector" (cheap spline hair)? And why is this fixed functionality in the first place?

Jakub Bokšanský and Daniel Meister: Neural Visibility Cache for Real-Time Light Sampling

jcgt.org/published/00...

"Falls"
vec3 x,c,p;x.x+=9.;
for(float i,z,f;i++<5e1;p=mix(c,p,.3),z+=f=.2*(abs(p.z+p.x+16.+tanh(p.y)/.1)+sin(p.x-p.z+t+t)+1.),o+=(cos(p.x*.2+f+vec4(6,1,2,0))+2.)/f/z)
for(c=p=z*normalize(FC.rgb*2.-r.xyy),p.y*=f=.3;f++<5.;p+=cos(p.yzx*f+i+z+x*t)/f);
o=tanh(o/3e1);

💾Releases! You want em? We got them!
Thank you to everyone who brought something to our party - it has been an honor!
files.scene.org/browse/parti...

Graphics Programming weekly - Issue 404 - August 17th, 2025 www.jendrikillner.com/post/graphic...

A snippet of the blog post, showing a short explanation of derivatives, as well as a graph of a quadratic function, and a graph of its derivative.

Derivatives, Gradients, Jacobians and Hessians – Oh My!
New mathy blog post to try and make some scary sounding terms less scary.
blog.demofox.org/2025/08/16/d...

Another option is to use Startpage, which gives you Google search without the AI overview (and no tracking etc.)

www.startpage.com

Lovely! Colormaps are very useful and I occasionally find myself looking for the 'best one' (typically one that is visually pleasing). But his takes it several steps further.

It's summer and TinyBVH updates are slow, but something cool happened nevetheless:
Florent Le Moël sends word that Python bindings for TinyBVH are now available.
Check out the repo:
github.com/FlorentLM/py...
Great stuff!

A log/log error graph of Monte Carlo integration of the function y=x between 0 and 1, using a couple different sampling strategies.

Toroidally Progressive Stratified Sampling in 1D
New Blog Post! See how to use a low discrepancy shuffler to make stratified sampling toroidally progressive.
blog.demofox.org/2025/08/03/t...