[4.3.0.1] Snowflake screamer or how window on-go changes are still somewhat hard for the game to handle

[TheOnyxGuy]

As the winter event of R'n'D started, one user reported the snowflakes in General Discussion. I went to check that and... indeed, it is true. But, weirdly enough, as I was switching between levelsets with different window sizes, and at one moment I just got sprite of a snowflake stretched to the entire window size with then the game just crashing and closing on me.

Have snowflakes already become sentient? Oh no...

SnOwFlAkE wIlL gEt YoU

rbrwbeukt.png (182.66 KiB) Viewed 12779 times

But, to be serious, these errors are probably still just leftovers of the window size problems we were encountering for several years already, and the snowflakes are one of the first things to be loaded.

[Holger]

Hi Eizzoux,

whoops, that looks really strange indeed -- is it possible to reproduce this problem in any way?

In fact, I once saw a custom menu animation stretched over the whole width of the window, but I don't know anymore if this was reproducible or happened only once.

these errors are probably still just leftovers of the window size problems we were encountering for several years already

Which problems are you talking about? Did I miss anything here? Please let me know more about it -- maybe I can reproduce and debug (and hopefully fix) those problems!

[TheOnyxGuy]

Just try switching between, let's say, an R'n'D and an MM levelsets, also occasionally play level, and that just might cause the game to randomly crash as the game window changes, that's how I got that error several times already.
Oh, also, that happens on Windows 10, at least

[Holger]

Never encountered such a crash when changing window sizes, so this might be a bug that only happens with the Windows versions (or that does not happen with the Linux version -- I will also try the Mac version for this problem).

Thank you for the bug report! I will try to reproduce and to fix it.

[Holger]

I have now tried to reproduce this using R'n'D on Windows 10, switching between classic (tutorial) level sets and level sets from the Supaplex collection (with different window size), but so far I was not able to either get those strange graphical bugs, nor did the program crash (but maybe it was not running long enough to trigger this problem).

If anybody should find a way to deterministically reproduce this problem (on Windows or other platforms), please let me know, This must be a hidden bug that I really would like to fix.

[TheOnyxGuy]

Just sayin', I'm specifically using R'n'D x64 with Windows 10 x64.

[Holger]

Just sayin', I'm specifically using R'n'D x64 with Windows 10 x64.

Yep, that's exactly the setup I also tested here (with the only possible difference that I used a virtual machine to run my Windows test system).

[TheOnyxGuy]

Recently, just as I downloaded the last update, I started messing around with levelsets, checking new stuff like the new quick level set info button, new editor icons and others, I started switching between levelsets, including the ones which have unique window sizes, and first got snowflake trails on blank background, reloaded the game, started switching again and then at some point got a new "snowflake screamer", which, this time, didn't crash my game. The game behaves the same, but visuals are getting completely messed up. What's even more interesting, I managed to switch to another levelset blindly and the huge snowflake switched to another one, which also for some reason passes some graphics through itself.

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Aside from these screenshots, I have this video footage of me just randomly switching between levelsets with different window dimensions and pretty much destroying the game's visuals more and more.
[Video link]
I have a new suspicion. Might that be a problem of window scaling, perhaps? I usually keep the game's window scale at 140% or 160%. Can that be a problem, perhaps? Like, I still can't find a solid logic behind that, it just happens sometimes.

[Holger]

Completely strange!

And I have never seen such effects or artifacts before!

When watching your YouTube video to document the effect, I noticed similar artifacts that apparently were not caused by snowflakes -- see the video at positions 2:06 and 2:24, in the lower right corner (well, covering a large part of the screen for a short time). This looks more like an artifact of the brown buttons in the top left corner, doesn't it?

I have tried to reproduce this on the same platform (Windows 10 / 64-bit version), but without success.

If anybody should have ever encountered similar "effects", or even finds a way to reproduce this, please let me know!

Until then, I have the suspicion that this problem could be limited to certain circumstances on a single machine...

[TheOnyxGuy]

Have you tried it with a different window scaling? I mean, like, with 160% like I had?
Also, it's not only related to the snowflakes, but to pretty much all global animations and toons in general.

[Holger]

Indeed I haven't tried that exact combination, so it may make the difference.

What I tried was (a) doing all kinds of tests in a Windows 10 VM (where the "VM vs. bare metal" might already make a difference), but using 100% window size only, and (b) doing all kinds of tests with different windows sizes, but on a Linux box.

I'll also check the combination "using R'n'D on Windows 10 with different window sizes".

[Holger]

I was finally able to randomly, but regularly reproduce this bug on my Mac.

And after long hours of debugging and nearly going crazy, I was finally able to fix it. *phew*

[TheOnyxGuy]

Oh wow, of all things, this? Neat. I still don't really know the exact setup for it, but it seems to be somewhat hardware-related. At least on some motherboards it was glitching out, on some it's fine. Seems unpredictable

[Holger]

Oh wow, of all things, this? Neat. I still don't really know the exact setup for it, but it seems to be somewhat hardware-related. At least on some motherboards it was glitching out, on some it's fine. Seems unpredictable

It really was kind of unpredictable, and only happened under certain circumstances. First of all, it never ever happened on my Linux workstation I usually use for all things R'n'D. Now that it's broken (most probably because of being over ten years old, and switching it off for a week of vacation, and I won't have time to build a new system for now), I use my Macbook for R'n'D development instead. And one week ago I saw that strange glitch for the very first time, which clearly only happens when it's snowing.

I tweaked a few internal parameters for testing (to let it snow immediately, with full amount of snow, which usually only happens on christmas), so I was able to see it more often. It only happened when changing the window size by loading artwork with different window size, like alternating between classic and BD style artwork. And I was finally able to track it down to being caused by destroying textures which have already being freed automatically by the (also freed) renderer when changing the screen size (which I did not know). It never gave any problems on Linux, and it only made some visual trouble on the Mac every now and then (but enough to be able to reproduce it by 10-20 times toggling artwork).

Reading the SDL docs more carefully could have saved me from this mess, as it states that destroying the SDL renderer also automatically destroys its textures (while everything else has to be manually freed, like SDL surfaces and so on, which are not tied to the renderer). But unlike usual memory, which gives you a nice Segmentation Fault when freeing it twice, what happens when double destroying a texture apparently highly depends on your environment...

I'm glad that it's fixed now, and that I know why it happened. This was really a strange looking bug!