This feed omits posts by jwz. Just 'cause.

Congress is about to dilute the safety mission of the Nuclear Regulatory Commission with toxic fallout — a second mission to keep nuclear industry profitable.

Posted Sat Jun 22 17:15:38 2024 Tags:

Louisiana Republicans passed a law to require every public school classroom to display a copy of the Ten Commandments.

This sectarian requirement obviously contradicts the First Amendment (combined with the subsequent amendment which says states can't do those things either). It prohibits establishment of religion. But we can't count on those Republican wreckers on the Supreme Court to honor that.

Posted Sat Jun 22 17:15:38 2024 Tags:

*Maryland governor issues pardons for 175,000 cannabis-related convictions.*

Marijuana should be legal, and people who were punished or might be punished for having it, transporting it or selling it should be pardoned.

Posted Sat Jun 22 17:15:38 2024 Tags:

*Stock traders are trying to beat the market — by copying lawmakers.*

Posted Sat Jun 22 17:15:38 2024 Tags:

Measures to limit overcrowding and avoid dangers in climbing Mount Fuji have the unjust side effect of requiring each climbers to (1) identify perself and (2) carry a snoop-phone.

If I ever go to Japan again, that is one thing I certainly won't do.

Posted Sat Jun 22 17:15:38 2024 Tags:

*The normalisation of dehumanisation in the Israel-Palestine conflict.*

Let's not lose sight of where we want to end up.

Posted Sat Jun 22 17:15:38 2024 Tags:

*‘I have seen the decline’: pesticides linked to falling UK insect numbers.*

Decreases in overall insect populations will cause repercussions through each ecosystem. Many animals (including humans) eat insects. Many plants depend on insects to pollinate them and disperse their seeds.

Posted Sat Jun 22 17:15:38 2024 Tags:

The Pentagon is thinking about using large numbers of more-or-less autonomous drones for fighting China.

This raises concerns that the drones will chose targets autonomously, and kill lots of civilians — something I expect Ukraine's drone controllers avoid, although Israel's drone controllers may not care.

Putting that issue aside, it seems like a good plan, but I don't see how the US can expect to be better at this than China.

Posted Sat Jun 22 17:15:38 2024 Tags:

The head of NATO argued for making more nuclear weapons.

More nuclear weapons than the US has cannot improve deterrence. With a sane enemy, the use of 100 nuclear weapons, producing a nuclear winter that would cause starvation around the world, is enough deterrent. With an insane enemy, 10,000 nuclear weapons would not be enough.

This provoked a lot of opposition, but I am sure that the businesses that would profit from making and deploying them will come up with lots of flimsy reasons in favor.

Posted Sat Jun 22 17:15:38 2024 Tags:

Everyone: Call on Canada to enforce its environmental laws against logging to export wood chips for burning.

Posted Sat Jun 22 17:15:38 2024 Tags:
It's as easy as [1], [2], [3]. #bibliographies #citations #bibtex #votemanipulation #paperwriting
Posted Wed Jun 12 19:10:11 2024 Tags:

SwiftNavigation

To celebrate that RealityKit's is coming to MacOS, iOS and iPadOS and is no longer limited to VisionOS, I am releasing SwiftNavigation for RealityKit.

Last year, as I was building a game for VisionPro, I wanted the 3D characters I placed in the world to navigate the world, go from one point to another, avoid obstacles and have those 3D characters avoid each other.

Almost every game engine in the world uses the C++ library RecastNavigation library to do this - Unity, Unreal and Godot all use it.

SwiftNavigation was born: Both a Swift wrapper to the underlying C++ library which leverages extensively Swift's C++ interoperability capabilities and it directly integrates into the RealityKit entity system.

This library is magical, you create a navigation mesh from the world that you capture and then you can query it for paths to navigate from one point to another or you can create a crowd controller that will automatically move your objects.

Until I have the time to write full tutorials, your best bet is to look at the example project that uses it.

Posted Tue Jun 11 15:05:10 2024 Tags:

My grandmother used to make a recipe from an old newspaper clipping. After decades the original clipping started to crumble so she replaced it with a new clipping when the newspaper re-ran the recipe. I struggled but eventually succeeded in making a recipe which matched my childhood memories. Sadly my childhood memories were romanticized and my grandmother’s original recipe didn’t make the pancakes stay floofed after they were done cooling off, but I hope you enjoy this improved version.

These pancakes rise by water under the batter turning into steam, so to keep the pan from getting cooled off by the batter it’s important to cook them in an iron skillet which has been given time to heat all the way through.

3 eggs
70 grams flour
120 grams milk
1 gram nutmeg
1 gram mint oil
Pinch of salt
6 grams powdered sugar
3 grams Lemon juice powder
20 grams Ghee

Preheat the oven with a skillet inside to 400 degrees. Leave it in for 15 more minutes after preheating. Mix together eggs, flour, milk, nutmeg, mint oil, and salt and beat thoroughly. When the oven is heated add ghee to the pan and put it back in to melt (about 2 minutes). After it’s done melting, pour batter on top. Bake for 20 minutes. Thoroughly mix powdered sugar and lemon juice powder and put it in a dusting wand. Sift completely over top.

Thanks for reading Bram’s Thoughts! Subscribe for free to receive new posts and support my work.

Posted Sat Jun 8 20:18:43 2024 Tags:

Back in the day when presumably at least someone was young, the venerable xsetwacom tool was commonly used to configure wacom tablets devices on Xorg [1]. This tool is going dodo in Wayland because, well, a tool that is specific to an X input driver kinda stops working when said X input driver is no longer being used. Such is technology, let's go back to sheep farming.

There's nothing hugely special about xsetwacom, it's effectively identical to the xinput commandline tool except for the CLI that guides you towards the various wacom driver-specific properties and knows the right magic values to set. Like xinput, xsetwacom has one big peculiarity: it is a fire-and-forget tool and nothing is persistent - unplugging the device or logging out would vanish the current value without so much as a "poof" noise [2].

If also somewhat clashes with GNOME (or any DE, really). GNOME configuration works so that GNOME Settings (gnome-control-center) and GNOME Tweaks write the various values to the gsettings. mutter [3] picks up changes to those values and in response toggles the X driver properties (or in Wayland the libinput context). xsetwacom short-cuts that process by writing directly to the driver but properties are "last one wins" so there were plenty of use-cases over the years where changes by xsetwacom were overwritten.

Anyway, there are plenty of use-cases where xsetwacom is actually quite useful, in particular where tablet behaviour needs to be scripted, e.g. switching between pressure curves at the press of a button or key. But xsetwacom cannot work under Wayland because a) the xf86-input-wacom driver is no longer in use, b) only the compositor (i.e. mutter) has access to the libinput context (and some behaviours are now implemented in the compositor anyway) and c) we're constantly trying to think of new ways to make life worse for angry commenters on the internets. So if xsetwacom cannot work, what can we do?

Well, most configurations possible with xsetwacom are actually available in GNOME. So let's make those available to a commandline utility! And voila, I present to you gsetwacom, a commandline utility to toggle the various tablet settings under GNOME:

$ gsetwacom list-devices
devices:
- name: "HUION Huion Tablet_H641P Pen"
  usbid: "256C:0066"
- name: "Wacom Intuos Pro M Pen"
  usbid: "056A:0357"
 
$ gsetwacom tablet "056A:0357" set-left-handed true
$ gsetwacom tablet "056A:0357" set-button-action A keybinding "<Control><Alt>t"
$ gsetwacom tablet "056A:0357" map-to-monitor --connector DP-1
  

Just like xsetwacom was effectively identical to xinput but with a domain-specific CLI, gsetwacom is effectively identical to the gsettings tool but with a domain-specific CLI. gsetwacom is not intended to be a drop-in replacement for xsetwacom, the CLI is very different. That's mostly on purpose because I don't want to have to chase bug-for-bug compatibility for something that is very different after all.

I almost spent more time writing this blog post than on the implementation so it's still a bit rough. Also, (partially) due to how relocatable schemas work error checking is virtually nonexistent - if you want to configure Button 16 on your 2-button tablet device you can do that. Just don't expect 14 new buttons to magically sprout from your tablet. This could all be worked around with e.g. libwacom integration but right now I'm too lazy for that [4]

Oh, and because gsetwacom writes the gsettings configuration it is persistent, GNOME Settings will pick up those values and they'll be re-applied by mutter after unplug. And because mutter-on-Xorg still works, gsetwacom will work the same under Xorg. It'll also work under the GNOME derivatives as long as they use the same gsettings schemas and keys.

Le utilitaire est mort, vive le utilitaire!

[1] The git log claims libwacom was originally written in 2009. By me. That was a surprise...
[2] Though if you have the same speakers as I do you at least get a loud "pop" sound whenever you log in/out and the speaker gets woken up
[3] It used to be gnome-settings-daemon but with mutter now controlling the libinput context this all moved to mutter
[4] Especially because I don't want to write Python bindings for libwacom right now

Posted Thu Jun 6 06:22:00 2024 Tags:

As I’ve mentioned previously if you want eventually consistent version control, meaning whatever order you merge things together has no impact on the final result, you not only need to have a very history aware merging algorithm, you also need canonical ordering of the lines. This cleanly dodges around the biggest issue in version control, which is what should you do when one person merges AXB and AYB as AXYB and another person merges them together as AYXB and then you try to merge both of those together. None of the available options are good, so you have to keep it from ever happening in the first place. Both people need to be shown AXYB as the order of lines in the merge conflict (or the other order as long as it’s consistent) and that way if either of them decided to change it to AYXB then that was a proactive change made afterwards and is not only a winner of the later meta-merge conflict, there isn’t even a conflict at all, it merges cleanly.

This flies in the face of how UX normally works on merge conflicts, which orders the conflicting regions by whether they’re ‘local’ or ‘remote’. How to do order better is an involved subject which I’ve covered thoroughly in older posts and won’t rehash here, but conflict UX I want to talk about more. Since the order of lines and whether they should be included if everything is smashed together blindly is assumed to be handled, that creates a question of how to detect and present conflicts. What’s going to be needed is a way of marking particular lines as conflicts and figuring out what should be marked. There should be some format of special lines similar to the conflict markers people are already familiar with as a way of presenting them to users in files. That format should include a way of saying which of the two sides individual lines came from.

The general idea is to determine ‘which side each line came from’ and if two lines whose ancestry are different are ‘too close together’ then they’re both marked as being in conflict. If successive lines have the same ancestry then if one of them is in conflict it taints the others. The simplest approach is that a single line of code which is present on both sides ends regions of conflict. Arguably it should be more than one line to declare peace, or that empty or whitespace only lines shouldn’t count towards it. I’m going to assume the simplest approach for a proof of concept.

An important case is when Alice adds a line to a function and Bob deletes the entire function. Obviously that should somehow be presented as a conflict but deleted lines are crucial to it. For that reason there needs to be some way of showing deleted lines in the conflict, definitely with proper annotations around them and possibly with the individual deleted lines commented out.

To detect conflicts each line is marked as ‘peaceful’, ‘skip’, ‘Alice won’, ‘Bob won’ or ‘both won‘. Once all lines are marked then the ones which are marked skip are, well, skipped. Other lines which border lines with a different marking which is not peaceful are marked as in conflict. Finally tainting is spread to neighboring lines which have the same state. Deleted lines are only presented to the user if they’re in conflict.

What to do in each case is best presented as a laundry list, so here goes. Each case is final-Alice-Bob.

missing missing missing: skip
missing missing present: Alice
missing present missing: Bob
missing present present: both (this is an unusual case but it can happen)
present missing missing: both (similar to the previous case)
present missing present: Bob
present present missing: Alice
present present present: peaceful

That seems to handle all the edge cases properly and covers the last of the theoretical details I needed to work out.

When a user resolves a conflict and does a commit it should first throw an error if conflict markers weren’t removed, then should assume the user edited the clean merge they would have seen if each line were presented verbatim without checking for conflicts. When doing a diff between the complete weave and the user’s final file version it should probably more heavily weight lines which were present than lines which were deleted but I’m not sure what the best way of doing that is and will probably make a prototype which doesn’t have any such heuristic.

Posted Sat May 25 22:08:52 2024 Tags:

PLA is a great 3D printing material with one major flaw. It’s the stiffest of available materials, not toxic, cheap, and prints easily. The main downside of it is that it melts at an annoyingly low temperature. It would be nice to have some material which is like PLA in all characteristics but has a higher melting temperature. It turns out that such a material exists and it is… PLA.

That last statement requires some explaining. The distinction is whether PLA is annealed or not. Annealing is a process where a material is brought up to a high temperature and then very slowly cooled down, causing it to be more crystalline (or at least lower energy) at the molecular level and thus stronger/tougher/having a higher melting point. PLA the material does this very well but if you apply the process to 3d printed parts they warp because internal stresses within the parts get released. It’s like the objects are made out of frozen rubber bands which were stretched out as the filament was layed down and heating it up allows them to spring shut.

The causes of this problem are that the filament wasn’t made hot enough when it was extruded and wasn’t cooled down slowly enough afterwards. The straightforward way of fixing this would be to do exactly that: make the filament so hot it’s a liquid when it comes out, then cool everything down slowly afterwards. That would require some kind of soluble support material which is solid at those high temperatures, printing everything at 100% fill because it’s a liquid, and keeping the entire 3D printer at those high temperatures. While this approach may work it’s unlikely the printer itself would still be cheap and reliable with all that literally getting cooked while it’s running.

A more practical approach may be to invent a PLA blend which anneals better. If PLA is interleaved with another material which forms a matrix around it, maybe that other material could melt at a much higher temperature, meaning it’s still frozen at the temperature PLA needs to be heated to to get it to anneal, so doing the annealing process post-printing wouldn’t cause the item to warp. The obvious candidate for this is carbon fiber. Maybe you could make carbon fiber PLA with massively more carbon fiber than anything currently available, to the point where the melting point is dramatically increased, then print using that and anneal later by taking the parts back up to the melting point of PLA but not the melting point of the combined material. Whether carbon fiber specifically or anything in general can get PLA to behave that way I don’t know, and obviously a brass nozzle couldn’t handle that material, but maybe some experimentation could result in a new type of filament which could make very high quality parts quickly and easily.

Thanks for reading Bram’s Thoughts! Subscribe for free to receive new posts and support my work.

Posted Thu May 9 16:27:28 2024 Tags:

TLDR: Thanks to José Exposito, libwacom 2.12 will support all [1] Huion and Gaomon devices when running on a 6.10 kernel.

libwacom, now almost 13 years old, is a C library that provides a bunch of static information about graphics tablets that is not otherwise available by looking at the kernel device. Basically, it's a set of APIs in the form of libwacom_get_num_buttons and so on. This is used by various components to be more precise about initializing devices, even though libwacom itself has no effect on whether the device works. It's only a library for historical reasons [2], if I were to rewrite it today, I'd probably ship libwacom as a set of static json or XML files with a specific schema.

Here are a few examples on how this information is used: libinput uses libwacom to query information about tablet tools.The kernel event node always supports tilt but the individual tool that is currently in proximity may not. libinput can get the tool ID from the kernel, query libwacom and then initialize the tool struct correctly so the compositor and Wayland clients will get the right information. GNOME Settings uses libwacom's information to e.g. detect if a tablet is built-in or an external display (to show you the "Map to Monitor" button or not, if builtin), GNOME's mutter uses the SVGs provided by libwacom to show you an OSD where you can assign keystrokes to the buttons. All these features require that the tablet is supported by libwacom.

Huion and Gamon devices [3] were not well supported by libwacom because they re-use USB ids, i.e. different tablets from seemingly different manufacturers have the same vendor and product ID. This is understandable, the 16-bit product id only allows for 65535 different devices and if you're a company that thinks about more than just the current quarterly earnings you realise that if you release a few devices every year (let's say 5-7), you may run out of product IDs in about 10000 years. Need to think ahead! So between the 140 Huion and Gaomon devices we now have in libwacom I only counted 4 different USB ids. Nine years ago we added name matching too to work around this (i.e. the vid/pid/name combo must match) but, lo and behold, we may run out of unique strings before the heat death of the universe so device names are re-used too! [4] Since we had no other information available to userspace this meant that if you plugged in e.g. a Gaomon M106 and it was detected as S620 and given wrong button numbers, a wrong SVG, etc.

A while ago José got himself a tablet and started contributing to DIGIMEND (and upstreaming a bunch of things). At some point we realised that the kernel actually had the information we needed: the firmware version string from the tablet which conveniently gave us the tablet model too. With this kernel patch scheduled for 6.10 this is now exported as the uniq property (HID_UNIQ in the uevent) and that means it's available to userspace. After a bit of rework in libwacom we can now match on the trifecta of vid/pid/uniq or the quadrella of vid/pid/name/uniq. So hooray, for the first time we can actually detect Huion and Gaomon devices correctly.

The second thing Jose did was to extract all model names from the .deb packages Huion and Gaomon provide and auto-generate all libwacom descriptions for all supported devices. Which meant, in one pull request we added around 130 devices. Nice!

As said above, this requires the future kernel 6.10 but you can apply the patches to your current kernel if you want. If you do have one of the newly added devices, please verify the .tablet file for your device and let us know so we can remove the "this is autogenerated" warnings and fix any issues with the file. Some of the new files may now take precedence over the old hand-added ones so over time we'll likely have to merge them. But meanwhile, for a brief moment in time, things may actually work.

[1] fsvo of all but should be all current and past ones provided they were supported by Huions driver
[2] anecdote: in 2011 Jason Gerecke from Wacom and I sat down to and decided on a generic tablet handling library independent of the xf86-input-wacom driver. libwacom was supposed to be that library but it never turned into more than a static description library, libinput is now what our original libwacom idea was.
[3] and XP Pen and UCLogic but we don't yet have a fix for those at the time of writing
[4] names like "HUION PenTablet Pen"...

Posted Thu May 9 00:01:00 2024 Tags: