WebP loading segfaults when built with 32 bit MSVC

[Starbuck5]

Hello,

I normally use the prebuilt binaries provided on releases, which have been great, but I was hoping to customize my SDL_image build (for pygame-ce distribution w/ libpng and libjpeg rather than stbimage).

How I compiled:
Visual Studio 2022
Built SDL from the SDL2 branch in a sibling directory as the Visual Studio project include paths expect
Built SDL_image from the SDL2 branch with no changes in Visual Studio
Tested using the showimage program

Results:
x64: Works great
Win32: showimage program can load other formats, but segfaults intermittently (75% of the time) on webp

I also tested the 32 bit prebuilt from the 2.8.0 release, which did not have this problem.

I tested several images from this page https://developers.google.com/speed/webp/gallery1 to make sure this wasn't isolated to a specific image.

I tried to debug further by putting printfs into IMG_Webp, and these modified builds actually started working when tested in pygame-ce (they still didn't work in showimage, because printf can't be used in an all SDL environment because it doesn't have the library?)

I made sure WebP reports successfully initialization using IMG_Init, and I tried to fix it also by turning off optimizations on IMG_LoadWebp_RW using #pragma optimize( "", off ).

I would like to get this resolved but I'm all out of debugging ideas, I'd appreciate any help from here. Thanks.

[sezero]

Assuming that you are using the webp dlls provided in the 2.8.0 release distribution:
Does the attached new build of webp dlls work? webp-dlls.zip

[Starbuck5]

I was using the ones in VisualC/external/optional, which I think are the same as the 2.8.0 release distribution.

OMG THOSE WORK!! 🙏

[sezero]

OMG THOSE WORK!! 🙏

The attached new rebuild of dlls work: Can you confirm?

[Starbuck5]

Yes, sorry for the imprecise language.

Tested the attached DLLs from webp-dlls.zip (x86) with my build of SDL_image, and WEBP loading is now successful 100% of the time.

[sezero]

OK, thanks for the confirmation!

Fixed in the SDL2 branch as of f7c1e9b

Cherry-picked to release-2.8.x bd8728e

Closing as fixed.

[Starbuck5]

Thanks for such a quick fix!

What did you change in the webp builds?

[sezero]

Nothing in the source, only a different toolchain. (Don't know why, but the old builds seem to had been made using an old compiler toolchain -- I had possibly forgotten updating them.)

[sezero]

@slouken: This warrants a patch release?

P.S.: I will update our libavif from 1.0.2 to 1.0.3 today or tomorrow in SDL2 and SDL3. Should I do that in release branch too?

[slouken]

@slouken: This warrants a patch release?

P.S.: I will update our libavif from 1.0.2 to 1.0.3 today or tomorrow in SDL2 and SDL3. Should I do that in release branch too?

Yes, go for it. I have a fix for PNG loading that I want to get in as well, so we'll probably do a 2.8.1 release in a couple weeks.