Joined February 2019
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36 Photos and videos
25 Oct 2025
Most BSDFs in the room are blended between diffuse and glossy, while photon mapping does not play well with non-diffuse BSDF. To overcome this, I added BSDF lobe splitting, so that vertex merging can still be performed if the BSDF contains at least 1 diffuse lobe. It works well!
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4 Oct 2025
There are too many sampling strategies in my renderer that I am no longer confident in adding a new strategy without breaking old ones. A chi^2 test for goodness of fit is useful in this case and has helped me finding a new bug in dielectric sampling code, even after 10 years...
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4 Jul 2025
Implemented BSDF evaluation and PDF query for microfacet-based normal mapping to support more light transport algorithms. For dielectrics, I need to make some adjustments to the equations in the original paper. Now I need to find a beautiful scene and test it.😉
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4 Jul 2025
Hint: those walls are flat quads and the glass ball is a perfect sphere without any dent. In case you are wondering what to look for in the image :)
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29 Jun 2025
First sensible output with microfacet-based normal mapping in Photon-v2 renderer. If the geometry comes with flat normal/tangent, it can preserve symmetricity for bidirectional light transport out of the box.
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12 Jun 2025
Priority based nested dielectrics can also be used for disambiguating overlapping volumes. In the following image, the blue sphere has the highest priority, followed by green and red spheres. Medium properties are obtained from the volume with highest priority.
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5 Jun 2025
Tracking medium interfaces was not as easy as I originally thought. Anyway, this is the Utah teapot with simple dielectric material, attenuated by Beer's law. Next step will be trying to put some liquid in there 🥹
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6 Jun 2025
A high quality one. Start to see some geometric imperfection.
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Tzu-Chieh Chang retweeted
18 Oct 2024
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13 Oct 2024
Today is Starship's fifth flight test, and the 30-minute launch window will open at 7 a.m. CT. Exciting times... 😎
I recommend watching this historical event on official SpaceX Twitter or @Erdayastronaut's YouTube live stream, as there are too many scams out there.
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22 Sep 2024
Recently, my focus shifted to restoring Linux compatibility of Photon renderer for a user. One interesting obstacle I encountered was that GitHub .zip downloads do not support symlinks. Now, everything, including the editor, is running smoothly on Linux. A happy ending!😀
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25 Aug 2024
Testing BVH-X recently. It's well known that BVHs of a higher branch factor can greatly improve ray tracing performance with SIMD optimizations. However, I'm surprised that a naively built BVH4 (scalar code) already has roughly the same performance as BVH2. Will test further.
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25 Aug 2024
Using the cyberpunk city scene again, fully diffuse. Building BVH4 with bucket-based SAH (exhaustively test all possibilities with backtracking). Will post some numbers later.
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13 Aug 2024
Rendering lights with the spectral density distribution obtained from Planck's law of black-body radiation, ranging from 1000 K to 12000 K.
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31 Jul 2024
Rendering the Power Station section of the recently released Caldera dataset with Photon-v2.
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31 Jul 2024
About the dataset: x.com/Activision/status/1818…
30 Jul 2024
The release of a new open-source data set, features the map Caldera from Call of Duty: Warzone for non-commercial use. This data set release contains near-complete geometry of Caldera and in-game character pathing. Read more 👇
bit.ly/3yhV8Ax
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6 Aug 2024
Refactoring my BVH implementation and found some issues that manifest in larger scenes like the Power Station. Note that some axis-aligned planes were missing.
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