Categories
Games Software Development

A Return to Strange Adventures in Infinite Space

Strange Adventures in Infinite Space is a game I remember fondly from the early 2000s – a simple and small game that could be played in the space of 20 minutes and was a lot of fun.

Screenshot of Strange Adventures in Infinite Space GPL, from the Linux port.

In 2005, the authors released the source code under the GPL, and I threw out a quick port of the demo only for Linux and promptly got distracted by other things. This port grew up into a more fully featured port by another individual.

A few months ago, I picked up a clean copy of the source and decided to tackle porting it properly. I also got in touch with the original authors and secured permission to redistribute the game data (since they had started releasing it for free) and was given their blessing to do so under the CC-BY-NC license.

The result is Strange Adventures in Infinite Space GPL, which now has it’s first set of public binaries available which include both a build of the game for modern 64-bit systems and the game data in a single, easy to deploy, bundle.

It’s been a interesting run – I’ve dug a lot deeper into the Infinite Space source code than I did last time and I know more about multi-platform porting, and especially about C++, than I did 15 years ago having been the steward of XSquawkBox for the past 5 years.

About the New Port

The new port started from pristine sources, so nothing from my original effort was kept.

The big goals were:

  • To eliminate local directory writing where possible.
    • When SAIS came out originally, it was perfectly acceptable for a game or application to write into its installation directory for save state or computed data – since Windows finally tightened up their default security, as has macOS, this is not a good solution anymore and needed to be addressed.
    • This is the likely the main source of the “You need to run it as Administrator” myth that exists around many game titles on Windows – running the game as Administrator avoids the permissions issues, but really, the game shouldn’t be writing into it’s installation directory anymore.
  • To modernise the codebase so it could run as a 64-bit native executable on 64-bit systems without issue.
    • This was needed as macOS has eliminated 32-bit binary support from it’s most recent release (10.15), meaning 32-bit builds can’t be produced anymore, let alone run. Also, with the rise of arm and aarch64, native 64-bit support would be useful to be able to support aarch64 in the future.
  • To try to untangle the codebase along the way.
    • In the original Read Me file, the original developer (Iikka Keranen) comments “The code is hideous. Sorry. This was my second Win32 app.” He wasn’t kidding – some bits have taken quite a bit of effort to work out what they’re actually doing so I could plot a path forward with modernisation.

Right now, the 1.6.0 release ports deal with points 1 & 2. They build on modern systems and have some adjustments to make life more pleasant on said modern systems.

The binaries are all native 64-bit and should run on the lastest releases of their respective operating systems without significant issues.

Untangling the codebase is harder and is still underway when I get a bit of time and inspiration to come back to it.

Will there be a Web Version?

Whilst it is a bit of a cool party trick to build things using emscripten so they can run in a browser, it’s actually quite a large amount of work to do that to SAIS right now.

It’s not off the cards, but it needs a significant internal rework to address one big issue: SAIS’s code base has multiple main loops, one for each scene.

This is a big no-no in the emscripten interface as the main loop has to be yielded so the browser can continue to run and process events, and ideally you need one super main loop which calls event handlers in the scene code. Refactoring the game’s scene tree and navigation to support this flow is not a trivial piece of work, and there’s other bits and pieces I want to sort out before then.

If emscripten had resolved the fundamental requirement by having a yield function instead of a main callback, this would have been a lot easier to do.

(Ed: I’ve just noticed ASYNCIFY on the emscripten page which seems like it’s new vs when I first assessed the work required – this provides a yield-like function, so maybe it’ll happen sooner after all)

Future Work?

I’m a lot busier right now than when I started this – I mostly did this is a bit of a space filler between tasks and to get a quick personal victory in the game porting space to help deal with my tendency towards suffering from imposter syndrome as I try to change my professional focus. I doubt I’ll be able to seriously return to this for a few months, so the big stretch goals won’t be happening anytime just yet, but I should be able to find the time for general maintenance stuff.

Categories
Tech

Raytracing – Floating Point Performance in 2020

So, I starting playing with Raytracers again – writing my own, following the guidance of Raytracing from the Ground Up. In doing so, I’ve gotten an opportunity to throw the code over various modern Multi-core machines to get a bit of an interesting look into FP performance in modern systems.

The raytracer in question is up on Github – it’s a simple raytracer that is FP intensive, but not particularly memory intensive. That said, if it’s compiled against debug libraries, it performs extremely poorly due to the Qt (Ed: and MSVC) debugging hooks. It doesn’t try to be too clever since most modern CPUs are fast enough to not need to be.

Last time I did this, it was with smallpt, a decade ago and the story was very different.

This time, rough times have been gathered for a 800×800 raytrace, 100 samples per pixel, with DoF simulation, intersecting with about 30 objects. This produces a minimum of 64 million ray intersections. A sample output is below.

CPUOSSTTC/TMTTCompiler
i7-3770kLinux23.1s4/85.3sg++ 7.5.0
i7-4770Windows24.0s4/86.5sMSVC 2019
Ryzen 7 3700XWindows23.2s8/162.7sMSVC 2019
i9-9900kWindows16.4s8/162.3sMSVC 2019
Rough Execution Times – by CPU

In the above table, STT is single-thread time (in seconds), C/T is the Cores vs Threads count. MTT is the multi-threaded time using all available hardware threads. Compiler is the compiler used to produce the binary.

This is a very unscientific test – testing has been done without load shedding, and is typically roughly taken from the worse non-outlier of 3-4 runs and rounded to the nearest 100ms. As my raytracer has a Qt UI, there is measurable UI overhead on Windows – that’s partially reflected by the difference in the 3770 and 4770 times.

[Edit 2020-06-30: I’ve written a basic CLI front-end to the raytracer and that’s also revealed there’s compiler optimisation differences too – I’ll post an update with new times when I’ve finished collecting them]

There is no explicit vectorisation in any build. Autovectorisation is enabled for AVX, but not AVX-512.

Windows builds were performed using MSVC 2019 without tuning biased towards intel or AMD and the same binary set was used on all systems tested.

The surprising result is just how poorly the Ryzen does compared to the older Generation i7s, given that the 3rd and 4th gen i7s are 7-8 years old now – it’s only saving grace is the fact it has double the cores packed into the chip.

It’s also important to note that this is purely a from-cache FP intensive task – it barely hits the memory interface, so the much faster memory interfaces in the later CPUs will not make a difference here.

Categories
Hardware Restoration Tech

Restoring an InfoTower 1000

Just a few notes from this one.

I rescued some old gear from ACMS with the intent of at least getting some of it operational whilst I kept a hold of it.

One of the items was a DEC InfoTower system with 7 CD-ROM drives.

The InfoTower was a DEC InfoServer 1000 in a steel cabinet (labelled BA56A) , with a single power supply to power it and all the drives connected.  InfoServers could also be used to drive tape and conventional disk units so they could be served to VMS and other systems over an ethernet LAN.

InfoTowers were available with 4 or 7 CD-ROMs, and whilst a lot of photos out there have these with the older caddied RRD42s and similar, the one I picked up has the RRD43 tray drives.

When I got around to inspecting it, it clearly had a blown power-supply – you could smell the electrolyte from the capacitors the moment the rear service cover was removed.

Interestingly enough, the InfoTowers use an old AT-style power supply which plugs into a backplane which connects to the power-connector made available to each drive bay.

You can replace the power-supply fairly trivially with a modern ATX one if you get a ATX to AT power supply loom.  (I picked up one from ebay).  The power supply you install will need to be no bigger than a standard profile power-supply (so the very large monsters like the old Corsair HX1000 are completely out of the question) and needs at least 3 Molex plugs.   The original supply was a 230W supply.  I used a cheap Aywun 500W power supply since I couldn’t get anything smaller with sufficient Molex plugs.

Unfortunately, most of the eBay looms have the switch soldered to them, rather than connected by spades (like the original AT supplies used), which is wasteful and needless as AC-safe spade connectors are quite cheap.  I cut the spade connectors off of the old power-supply’s switch leads and spliced them onto the switch-cable from the loom.  That said, if I had uncrimped spade shoes and insulators, that would have been a better choice than using the old connectors.

One trap to watch, however, is that the pin-out of the P8/P9 connector on the backplane is the reverse of the convention from PCs – whilst the two connectors are side-by-side, you must connect them with the ground wires outside, not in the middle.  (You should double-check this before you swap the supply over, but I doubt there’s that much variance in the units).  Fortunately the PCB is labelled, so a bit of investigative work should help you verify this before you smoke your new power supply.

AUI to 10Base-T (Twisted-Pair) adapters are also fairly easy to get hands on these days too – I was able to pick up a few more so I’ll have enough to hook up my MicroVAXen as well as the Infoserver.

Categories
Flying

Wind Correction on the HP48/50

Out of frustration with how slow working on an E6B can be during flight planning, I’ve been looking into electronic options for replacing it that do not involve buying an overpriced specialised calculator.

Whilst solutions like the CX-2 can be used in the US in exams, they can’t be used here, which defeats any benefit of using a type specific calculator over a more generic programmable.

Also, the pricing is such that a CX-2 costs about 2/3rd the price of a good programmable like the HP50G.

So I’ve opted to buy a 50G and implement as much of the E6B functionality as is practical for planning.

My initial efforts are as below!

Wind Correction on the HP50G (easily adapted to the non-CAS 48G by removing the →NUM instructions and the UNROT instructions with ROT ROT).

≪ 'curTAS' STO ≫ 'TAS' STO
≪ DUP curWHT - NEG curWV DUP2 WCA UNROT GS UNROT + →NUM SWAP →NUM ≫ 'TRKT' STO
≪ 'curWV' STO 'curWHT' STO ≫ 'WV' STO
≪ DUP2 WCA COS curTAS × UNROT SWAP COS × - ≫ 'GS' STO
≪ SWAP SIN × curTAS ÷ ASIN ≫ 'WCA' STO
{ TAS WV TRKT } MENU

These should all be put into their own folder. They work using globals to store values that carry over between specific operations.

It’s also written with RPN mode in mind. I’m not entirely sure how anybody gets anything done fast on a calculator using algebraic modes.

Oh, and set Degrees for angles unless you do your flight planning in Radians.

Using the above:

Change to the folder, and select the custom menu.

Punch in your TAS, press the TAS softkey.

Punch in your wind as two values – the heading and velocity – and press the WV softkey.

Punch in your desired track and press TRKT. The heading correcting for wind and ground speed will pushed onto the stack.

You only need enter a new WV or TAS if they change – they will persist between multiple TRKT operations.

Categories
Music Photography

Japan Music Festival at the Roller Den, Sydney

I tagged along to the JMF on a whim, partially as a fan of JRock/JPop – and partially as a photographer looking for somewhere to practice my camera-craft during my off-season.

It was a great show.  Ended up buying Jill’s and kaimokujisho’s albums.  Should have picked up Sparky’s album too, but I was suffering pretty badly from the volume levels and was trying to make it out without spending all of my cash.

Unfortunately for me, I made the amateur’s mistake of not taking earplugs with me – my ears finally stopped ringing 3 days later.

It was a great first outing for my new second-hand 70-200 2.8 VR, which performed admirably in the conditions.  I had also completely forgotten some of the crazy with the D3 and the space remaining counter, so I thought I was running out of space by the end of kaimokujisho’s set – many poor (but potentially salvageable) bursts got deleted, and I thought I had significantly less space during 101A’s set than I actually did, so shot hyper conservatively…  then I discovered about 3 minutes into Jill’s set I had a whole memory card free.  I’ll try to remember about the damned counter next time.

Categories
Software Development

Detecting Transaction Failures in Rails (with PostgreSQL)

So, Rails4 added support for setting the transaction isolation level on transactions. Something Rails has needed sorely for a long time.

Unfortunately nowhere is it documented how to correctly detect if a Transaction has failed during your Transaction block (vs any other kind of error, such as constraints failures).

The right way seems to be:

RetryLimit = 5 # set appropriately...

txn_retry_count = 0
begin
  Model.transaction(isolation: :serializable) do
    # do txn stuff here.
  end
rescue ActiveRecord::StatementInvalid => err
  if err.original_exception.is_a?(PG::TransactionRollback)
    txn_retry_count += 1
    if txn_retry_count < RetryLimit 
      retry
    else
      raise
    end
  else
    raise
  end
end

The transaction concurrency errors are all part of a specific family, which the current stable pg gem correctly reproduces in it’s exception heirachy. However, ActiveRecord captures the exception and raises it as a statement error, forcing you to unwrap it one layer in your code.

Categories
Software Development

On Python and Pickles

Currently foremost in my mind has been my annoyances with Python.

My current gripes have been with pickle.

Rather than taking a conventional approach and devising a fixed protocol/markup for describing the objects and their state, they invented a small stack based machine which the serialisation library writes bytecode to drive in order to restore the object state.

If this sounds like overengineering, that’s because it is. It’s also overengineering that’s introduced potential security problems which are difficult to protect against.

Worse than this, rather than throwing out this mess and starting again when it was obvious that it wasn’t meeting their requirements, they just continued to extend it, introducing more opcodes.

Nevermind that when faced up against simpler serialisation approaches, such as state marshalling via JSON, it’s inevitably slower, and significantly more dangerous.

And then people like the celery project guys go off and make pickle the default marshalling format for their tools rather than defaulting to JSON (which they also support).

Last week, I got asked to assist with interpreting pickle data so we could peek into job data that had been queued with Celery. From Ruby.  The result was about 4 hours of swearing and a bit of Ruby coding to produce unpickle. I’ve since tidied it up a bit, written some more documentation, and published it (with permission from my manager of course).

For anybody else who ever has to face off against this ordeal, there’s enough documentation inside the python source tree (see Lib/pickletools.py and Lib/pickle.py) that you can build the pickle stack machine without having to read too much of the original source.  It also helps if you are familiar with Postscript as the pickle machine’s dictionary, tuple and list constructors work very similarly to Postscript’s array and dictionary constructs (right down to the use of a stack mark during construction).

Categories
Photography

Animania Sydney 2011 Photos and Wrap-up

Well, Animania has come and gone.  I’ve posted my photos up to Flickr as usual.  Spent plenty of time chatting with Kris from whatabigcamera.com and a few other of the regular anime convention photography crowd whom I’ve been interacting since I got back into things.

Very low shutter count again this time – I think only 100 for the entire weekend over both cameras, and even that may be higher than reality.  After SMASH! I’m finding I’m a lot more selective over how I take shots, and I’m shooting a lot more with Flash Exposure Bracketing turned off, so I’m losing a few more “would have been good” shots than I used to, but have a lot less to cull overall, and the average quality is a lot higher.

The bulk of Saturday’s photos were taken single strobe – the later ones done with strobe off camera.  Mostly used the 5D, but took a few notables with the 50D + 50mm/1.8 combo mostly so I would have some material to defend my “you can do this with cheap, mainstream gear” claims. 🙂

The majority of Sunday’s photos were taken dual strobe – main off camera, on-camera unit for fill.  Having two 580s is handy that way.  Only took the 5D, but switched between the 70-200 and the 17-40 a fair bit.  Really need to pick up a 24-70 at some point.

Categories
Photography

SMASH 2011 Photos and Wrap-up

SMASH! has come and gone. It was an excellent effort given it was it’s first time at the Sydney Convention Centre.

Unfortunately, I was quite sick this past week and have only just gotten over that – so I cut my kit down heavily (I only brought one camera, 2 lenses and my speedlights), kept my activity down to a pretty low level and literally only took a few (about 40 total) photos.

To contrast, at both this year and last year’s Supanovas, my shot counts were up around 2000 photos for the whole weekend, of which I have to cull pretty heavily to get down to the 100-200 photos that get posted. Also, because I’ve taken so many photos of so many people, I feel compelled to at least publish some of the poorer photos if they’re still ‘viable’ because it features a cosplayer who has gone to great efforts to make their costume, etc, and I simply don’t have a better photo of them.

This time, because it was so short and sweet, the culling and selection was extremely easy, and the quality of the results compared to some of the other events speaks for itself.

The gallery of photos can be found on Flickr.

Technical Details

(Because for once, my workflow stripped the EXIF – I’ll work out why later…)

All photos were taken with an EOS 5D Mk1 with EF 70-200mm f/2.8L IS. (I had my EF 17-40mm f/4L in my bag, but didn’t use it at all).

The first 6 (predominantly outdoor) photos had fill-flash from a single on-camera Speedlite 580EX II with Rouge Flexible Flash Bounce Card. After I shot the first few photos, I also connected the Speedlite to a CP-E3 battery pack to improve it’s cycle time

The last 6 (indoor) photos were lit using an off-camera Speedlite 580EX II with Rogue Flexible Flash Bounce Card. Triggering was done via a standard Canon ST-E2 trigger. Flash held by captive flash bunny (thanks Retro!) – the camera weighs about 3kg in this configuration and I can’t balance the 70-200mm for conventional shooting one handed without introducing a LOT of shake to the camera.

All flash metering was Automatic. No Auto Exposure Bracketing or Flash Exposure Bracketing (FEB) was in use.

All post-production was done in Aperture from Camera RAWs. All edits are crop, exposure, dynamic range, and vignetting only. For once, I needed to do almost no cropping.

Categories
SCA

Spring War Photos

Mordenvale‘s Spring War has come and gone for this year. It was a good event with great fighting (although the first day of war saw me forced to retire due to hand injury)

I took my full camera kit with me to the event and got some nice photos during the first few rounds of the “Attain Speed” tournament.

These are up on Flickr.