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apocalypses

32 karma · joined September 22, 2018

C++ Engineer at Veed

https://veed.io

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apocalypses··on OpenGL: Mesh shaders in the current year
Saying WebGPU “only” adds compute shaders is crazy reductive and misses the point entirely for how valuable an addition this is, from general purpose compute through to simplification of rendering pipelines through compositing passes etc.

In any case it’s not true anyway. WebGPU also does away with the global state driver, which has always been a productivity headache/source of bugs within OpenGL, and gives better abstractions with pipelines and command buffers.

apocalypses··on Tilde, My LLVM Alternative
I massively disagree. It would have taken the author approximately 1 minute to write the following high quality hack-n-slash commit message:

``` Big rewrites

* Rewrote X

* Deleted Y

* Refactored Z ```

Done

apocalypses··on Debugging memory corruption: who the hell writes “2” into my stack? (2016)
There’s address sanitizer on newer versions of visual studio now but in my experience getting it to actually work with all of your projects’ dependencies can be very hit and miss. Windows Debug build config also does a lot more memory checking (part of the reason it’s so slow) so you’re not totally screwed for automated tools.
apocalypses··on Error codes are far slower than exceptions
Really interesting article. For me this was an important takeaway:

>Although it should fail gracefully, it does not need to be optimised for failure.

apocalypses··on Airbnb S-1
Apple
apocalypses··on LLVM Clang 12 Merges Support For x86_64 Microarchitecture Levels
One thing LLVM bitcode still can’t do is retain information about preprocessor directives, eg any platform specific code for AVX2 vs SSE4 etc. So unless you aim to write intrinsic free code it’s usually less performance/reliable to rely on compiler automatic vectorisation, which results in worse codegen overall.
apocalypses··on Fast Inverse Square Root
Though worth noting only for specific AVX-512 CPUs.

Though you can still have vectorised support for regular precision for AVX2.

apocalypses··on Using all-Apple Thunderbolt hardware to kill my MacBook
I have my own USB-C crappy story. I have a 2020 MacBook Pro 16” with bootcamp installed. Recently I bought a USB-C hub, if I try to boot into windows (hold alt at Apple logo) the machine literally cannot boot. At all. I have to disconnect the hub in order to make any progress.
apocalypses··on Lidar: Peek into the Future with iPad Pro
Depends on what you’re comparing to what. Big spinning lidars on cars are still expensive (few thousand dollars) but are coming down on price. Handheld 3D scanners on the other hand might start to become obseleted by a combination of cheap phone camera + lidar (really tof) sensors that are evidently cheap enough to put on phones. They can actually produce really high quality (SLAM) maps - Apple has figured out that they can have a much faster initial mapping phase by not having to do monocular mapping for their AR. So I guess I’m saying it’s cheaper and a bit worse, but it’s rapidly getting better.
apocalypses··on Lidar: Peek into the Future with iPad Pro
I work at a company that does lidar SLAM. You can actually produce really high quality maps/slam with lidar/tof sensors, and it’s a lot more robust/dense than visual/imu mapping.
apocalypses··on Lidar: Peek into the Future with iPad Pro
Maybe I screwed it up, I’m not the best developer ever. I took their sample code to extract the depth data from front camera and this worked - switching to .back caused it to return a nil device, so didn’t really know where to go after that.
apocalypses··on Lidar: Peek into the Future with iPad Pro
I've had a play around with the new ipad. The big problem is (as far as I can see), absolutely no way for a developer to get access to the underlying depth data.

I'm assuming it's coming in the next version of iOS, because you _can_ get access to the faceid depth data in a useful format.

apocalypses··on Making the obvious code fast (2016)
Swift can also auto vectorise these simple loops, but only with the right combination of compiler flags.

https://swift.godbolt.org/z/JmtOMx

apocalypses··on Minih264 – Minimalistic, single-header library for encoding H264/SVC
I found this very interesting, particular the comparison to x264 (which I had never heard of).

Looking into it I found x264 looked really easy to use with a nice C api but was encode only - does anyone know of a library very similar to x264 which is both encode/decode?