mattpharr

6 ms·

1.
by mattpharr 2mo ago
Not just for software, but more generally for technology that influences the movie industry: https://www.oscars.org/sci-tech
2.
by mattpharr 11mo ago
Minimizing the ray payload for GPU was definitely part of why we didn't add that. (Though it does pain me sometimes that we don't have it in there.) And, PBR being a textbook, we do save some things for exercises and I believe tha
3.
by mattpharr 2y ago
How would one link to a physical object? If this is what you’re asking: there are (perhaps too discreet) links at the bottom of each page to Amazon and MIT Press to purchase the physical book.
4.
by mattpharr 3y ago
In the 4th edition, there's no support for RGB rendering--it's always and only spectral. And admittedly the spectral rendering option in earlier editions wasn't great. We didn't always correctly distinguish between illum
5.
by mattpharr 3y ago
I love the Watt and Watt "Advanced Animation and Rendering Techniques" book as well; it was IMHO the best book on those topics in its time.
6.
The 4th edition of Physically Based Rendering is now freely available online(pbr-book.org)
16 points by mattpharr 3y ago|2 comments
7.
by mattpharr 3y ago
The physical book was published 6 months ago, and per agreement with the publisher, the contents are now freely available online as well. The book's blurb: Photorealistic computer graphics are ubiquitous in today's world, widely u
8.
by mattpharr 3y ago
Also related as far as the programming model: C* on Connection Machines and the C dialect used on MasPar systems in the 1980s. There is some discussion in the ispc paper: https://pharr.org/matt/assets/ispc.pdf
9.
by mattpharr 3y ago
> I would expect a shader could do a credible job of emulating all of these. The key is that it is necessary to know the coherence of the light arriving at the surface in order for a shader to accurately model reflection. (See Figure 13
10.
by mattpharr 4y ago
The irony of such a post on a website with the domain name “y combinator”…
11.
by mattpharr 4y ago
Rejection sampling is not a good choice here. First, the cost is 2 FMAs * the cost of generating 2 random numbers * the number of rejection sampling iterations. On average, you reject (4-pi)/4 ~= 0.25 of the time. However, if you'
12.
by mattpharr 4y ago
FWIW that algorithm for uniform floating-point sampling in [0,1] is actually originally due to: Walker, Alastair J. “Fast generation of uniformly distributed pseudorandom numbers with floating-point representation.” Electronics Letters 10 (
13.
by mattpharr 5y ago
> Are there alternative tools that focus on rewriting code to maximise performance while keeping error below some configurable bound? There are! See followup work by @pavpanchekha and others on "Pherbie", which finds a set of P
14.
by mattpharr 5y ago
> I'd be happy to pay the author (note, not donate*) for this corpus online. Lucky for you, we have a Patreon. Looking forward to your support!
15.
by mattpharr 5y ago
Yeah, about that prediction... Progress continues, but Fall 2021 is more likely for an online edition and then printed copies in the first half of 2022. (I suppose we should update the website.)
16.
by mattpharr 5y ago
Extra pedantic: no, because "physically" ends in "-ly". :-) (Rule 3 here: https://www.grammarbook.com/punctuation/hyphens.asp )
17.
by mattpharr 5y ago
> It’s good for linear algebra with long vectors and large matrices, but SIMD is useful for many other things besides that The main goal in ispc's design was to support SPMD (single program multiple data) programming, which is more
18.
by mattpharr 6y ago
No, the actual publisher (Elsevier) printed a batch of terrible quality books. This led to our ending our relationship with them. We are in the midst of finding a new publisher for the 4th edition; not repeating that disaster is of great im
19.
by mattpharr 6y ago
(PBRT author, here) pbrt is the Physically Based Ray Tracer that is described in the Physically Based Rendering book.
20.
by mattpharr 6y ago
So -20480 works out to be 0xAFFF. My trusty copy of "What's Where in the Apple", which includes a catalog of where everything is in memory, says that the routine to write the VTOC from its in-memory buffer to disk starts at $
21.
by mattpharr 7y ago
Workin' on it. :-) Note that the third edition came out roughly 5 years ago now, not 10.
22.
by mattpharr 8y ago
Thanks! Also fixed and will also go live in a little bit.
23.
by mattpharr 8y ago
Nice find! In general, you can send errata/bugs to authors@pbrt.org, but we got this one. :-) It looks like an equation that MathJax wasn't happy with. I've got it fixed now and will include that fix in a push to the site in
24.
by mattpharr 8y ago
It's pretty much a big hack. The book was originally written in TeX, with lots of macros on top. We hacked together a custom translator (~3k loc, written in golang) that parses the TeX and generates the site. Then MathJax to render the
25.
by mattpharr 8y ago
FWIW, in the Physically Based Rendering book, we also discuss data-oriented design ( https://en.wikipedia.org/wiki/Data-oriented_design ) as a potential alternative implementation approach, which would be the most natu
26.
by mattpharr 8y ago
Correct: it generates a surface light field from a set of RGBZ images that sample the scene surfaces. In turn, that's simplified into a set of alpha-textured quads that very accurately represent the scene from a specified headbox. View
27.
by mattpharr 8y ago
Post on nice interactions with the LLVM team coming up in a few days. :-)
28.
by mattpharr 9y ago
IMHO, the problem with the device model is that it imposes a bunch of unnecessary overhead on the programmer for cases where memory is shared and you're running on the same processor. If I just want to call a function, pass some parame
29.
by mattpharr 9y ago
Original ispc author here. I have no idea how performance compares to OpenCL on CPUs today, but it was in the same ballpark a few years ago. The big difference is that OpenCL imposes a device model which is (IMHO) ridiculous if you're
30.
by mattpharr 10y ago
No worries! The publishing industry has gotten worse in a lot of ways in the ~10 years since we did the first edition. The whole for-profit academic journals thing makes me sad in general, etc. However, it's also impressive how much wo

More ›