Sign in

Pablo Delgado

@pablode.bsky.social
77 followers 49 following 29 posts

Rendering @ Chaos. Personal projects: github.com/pablode

PostsRepliesMedia
Pablo Delgado @pablode.bsky.social · 15/05/2026
In the future, I may try some ideas to reduce the memory footprint even more: - do the same for 'uniform' interpolation - encode floats in [0/-1,1] as 16-bit UNorm/Snorm - hash primvars, store and refcount the GPU buffers in a global registry
000
Pablo Delgado @pablode.bsky.social · 15/05/2026
Implemented some basic 'primvar analysis' in Gatling. The idea is to detect patterns in secondary primvars (not part of vertex layout) and modify data & interpolation. For now, just checking for constant values, which is surprisingly effective for some assets.
110
Pablo Delgado @pablode.bsky.social · 14/05/2026
New blog post: pablode.com/posts/hydra-...
pablode.com
Primer on writing a Hydra render delegate
A practical introduction to OpenUSD Hydra and the basics of writing a custom render delegate.
000
Pablo Delgado @pablode.bsky.social · 06/04/2026
There are some pretty nice test cases in this glTF issue which I'm looking forward to adding to the test suite: github.com/KhronosGroup...
000
Pablo Delgado @pablode.bsky.social · 06/04/2026
Currently implementing Gaussian splatting in guc (glTF to USD converter) so that it can be released as soon as the extension comes out of RC status.
100
Pablo Delgado @pablode.bsky.social · 28/03/2026
I also hooked it up to the USD animation system, so that it matches playback and can be controlled with the usdview slider.
010
Pablo Delgado @pablode.bsky.social · 28/03/2026
This weekend I added support for the MaterialX <time> and <frame> nodes to Gatling. Procedural materials can now be animated over time, such as this clock authored by Roberto Ziche:
121
Pablo Delgado @pablode.bsky.social · 25/01/2026
Since the renderer is used as a Hydra render delegate, this is the concern of the host application (usdview). I just pass it some CPU memory.
000
Pablo Delgado @pablode.bsky.social · 18/01/2026
In general, it was nice getting to know Metal a bit - and I can't wait writing some user land code on my MacBook Air! Btw: Vulkan backend is ~3,8k LOC and Metal ~2,2k LOC.
020
Pablo Delgado @pablode.bsky.social · 18/01/2026
As these functions don't have access to intrinsics, we need to pass them along as part of their signature. Which the function tables are parameterized with. Here's an example of how the ray generation shader signature ends up looking with two ray payloads:
100
Pablo Delgado @pablode.bsky.social · 18/01/2026
Closest-hit shaders and miss shaders need to be emulated. They are compiled with their entry points being "visible" and are invoked from visible function tables (VFTs) based on the traversal result. For each payload type we have 1x IFT and 2x VFTs.
100
Pablo Delgado @pablode.bsky.social · 18/01/2026
An important difference between the graphics APIs is that Metal only has 'intersection' shaders that are invoked for non-opaque geometry. This is what I map any-hit shaders to. Their function addresses are stored in an intersection function table (IFT), similar to an SBT.
100
Pablo Delgado @pablode.bsky.social · 18/01/2026
On the API side I use metal-cpp and for shaders I partially implement the GLSL_EXT_ray_tracing extension in SPIRV-Cross. It's a bit hacky and it only supports the features I need, but overall content agnostic. Ideally it's transitionary until Slang or KosmicKrisp's compiler can be used.
130
Pablo Delgado @pablode.bsky.social · 18/01/2026
Finally finished Gatling's Metal backend! Here's a teaser of NVIDIA's USD / MDL sample scene 'Attic' running on macOS. What's special about the backend is probably that it uses the same GLSL code as the Vulkan backend, complete with hardware ray tracing. How does that work?
2152
Reposted by Pablo Delgado
Sebastian Aaltonen @sebaaltonen.bsky.social · 16/12/2025
My "No Graphics API" blog post is live! Please repost :) www.sebastianaaltonen.com/blog/no-grap... I spend 1.5 years doing this. Full rewrite last summer and another partial rewrite last month. As Hemingway said: "First draft of everything is always shit".
sebastianaaltonen.com
No Graphics API — Sebastian Aaltonen
Graphics APIs and shader languages have significantly increased in complexity over the past decade. It’s time to start discussing how to strip down the abstractions to simplify development, improve pe...
19475194
Pablo Delgado @pablode.bsky.social · 10/12/2025
Blog post on motion blur rendering (which is impressively thorough) by Alex Gauggel gaukler.github.io/2025/12/09/n...
gaukler.github.io
Notes On Motion Blur Rendering
Introduction
0136
Pablo Delgado @pablode.bsky.social · 07/12/2025
This scene from WireWheelsClub looks like this out of the box - no editing was required. Performance is not a priority right now, but is good enough with this simple lighting on an RTX 2060 @ WQHD
000
Pablo Delgado @pablode.bsky.social · 07/12/2025
There are still some minor issues to resolve, including getting rid of static state (for multiple viewports) and implementing support for orthographic cameras.
100
Pablo Delgado @pablode.bsky.social · 07/12/2025
Spent some time this weekend updating Gatling’s Blender integration to the latest 5.0 release.
110
Reposted by Pablo Delgado
Christoph Peters @momentsingraphics.bsky.social · 30/10/2025
Ray marching is a common approach to GPU-accelerated volume rendering, but gives biased transmittance estimates. My new #SIGGRAPHAsia paper (+code) proposes an amazingly simple formula to eliminate this bias almost completely without using more samples. momentsingraphics.de/SiggraphAsia...
A cloud rendered using jackknife transmittance estimation and the formula used to do so.
413928
Pablo Delgado @pablode.bsky.social · 12/10/2025
As usual, you can find it on GitHub: github.com/pablode/usds...
github.com
GitHub - pablode/usdshadeview: usdview plugin for inspecting shading networks
usdview plugin for inspecting shading networks. Contribute to pablode/usdshadeview development by creating an account on GitHub.
000
Pablo Delgado @pablode.bsky.social · 12/10/2025
Btw, a few weeks ago I released a small plugin for usdview. It allows inspection of UsdShade networks using a custom Qt node graph. It’s open source, lightweight and simple to install.
130
Reposted by Pablo Delgado
Yining Karl Li @yiningkarlli.bsky.social · 22/06/2025
The Pixar RenderMan team has a paper out at HPG 2025 this week about the architecture of RenderMan XPU. There's a lot of interesting details in the paper- definitely a worthwhile read! diglib.eg.org/bitstreams/d...
diglib.eg.org
1285
Pablo Delgado @pablode.bsky.social · 28/06/2025
Source code on GitHub: github.com/pablode/cg-a...
000
Pablo Delgado @pablode.bsky.social · 28/06/2025
Small weekend experiment: ported an LCD shader from Blender to #MaterialX (originally authored by PixlFX)
110
Reposted by Pablo Delgado
Yining Karl Li @yiningkarlli.bsky.social · 19/03/2025
We just posted a recording of the presentation I gave at DigiPro last year on Hyperion's many-lights sampling system. It's on the long side (30 min) but hopefully interesting if you like light transport! Check it out on Disney Animation's website: www.disneyanimation.com/publications...
disneyanimation.com
Walt Disney Animation Studios - Publications
We engage with the global research community through collaborations with universities around the world, publications in academic journals and participation in top-tier conferences.
14710
Pablo Delgado @pablode.bsky.social · 11/03/2025
www.youtube.com/watch?v=BUpD...
youtube.com
2D Gaussian Ray-Tracing is the future!
YouTube video by Oliver Markowski
010
Pablo Delgado @pablode.bsky.social · 11/03/2025
Implemented USD point instancer primvar support in my toy renderer the last few days. Can now render this 2D Gaussian Splatting (2DGS) scene with a single mesh & MaterialX material. (Created by Oliver Markowski with Houdini, link see below ⬇️)
151
Reposted by Pablo Delgado
Christoph Kubisch @pixeljetstream.bsky.social · 30/01/2025
Thanks to a lot of colleagues' great work, happy to share Vulkan samples for RTX Mega Geometry. They should run on all RTX GPUs using today's new drivers github.com/nvpro-sample... github.com/nvpro-sample... github.com/nvpro-sample... github.com/nvpro-sample...
github.com
GitHub - nvpro-samples/vk_animated_clusters: Sample that uses VK_NV_cluster_acceleration_structure to animate meshes for ray tracing
Sample that uses VK_NV_cluster_acceleration_structure to animate meshes for ray tracing - nvpro-samples/vk_animated_clusters
211335
Reposted by Pablo Delgado
Jonathan Stone @sheriffstone.bsky.social · 21/01/2025
Highlighting one of the key contributions in MaterialX v1.39.2, Masuo Suzuki at NVIDIA contributed the Chiang Hair BSDF, seen below in NVIDIA RTX, which opens the door to the authoring of cross-platform, customizable hair shading models in MaterialX and OpenUSD. github.com/AcademySoftw...
Three different examples of the Chiang Hair BSDF in MaterialX v1.39.2, rendered in NVIDIA RTX.
1204
Reposted by Pablo Delgado
Ignacio Castano @icastano.bsky.social · 04/01/2025
Wrote a blog post about my development process and the tools I’ve built to develop the Spark codecs: ludicon.com/castano/blog...
ludicon.com
Tools for GPU Codec Development – Ignacio Castaño
23310
Pablo Delgado @pablode.bsky.social · 03/01/2025
Lastly, implemented proper support for AOVs including those used for picking (primId, instanceId, elementId). (asset: standard shader ball) (4/4)
000
Pablo Delgado @pablode.bsky.social · 03/01/2025
To reduce the memory footprint, I first run the geometry through meshoptimizer which culls and deduplicates vertices. Next, the data is compressed with blosc. The results are quite good. Decompression only happens when a BLAS is rebuilt. (3/4)
100
Pablo Delgado @pablode.bsky.social · 03/01/2025
Furthermore implemented #MaterialX geompropvalues (MDL scene data), and GeomSubsets. This required quite some code rewriting, as I now store a copy of the CPU geometry data in the renderer itself. Here’s a render of stehrani3d’s MaterialEggs which make use of these features (2/4)
110
Pablo Delgado @pablode.bsky.social · 03/01/2025
Made good progress with gatling lately, and one of the new features is graphical tests. They primarily run on GitHub Actions using Mesa lavapipe (supports ray tracing). Thresholds are specified as USD render settings, diff images are uploaded as artifacts (1/4)
120
Pablo Delgado @pablode.bsky.social · 03/01/2025
Hello 🦋 community!
020