VRAM compression import options help needed

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:bust_in_silhouette: Asked By AltoWaltz


I am working on 2.5D game and realized that RAM usage is too high. So I compressed large spritesheets with VRAM compression and by that RAM usage is reduced for even up to 70%. This has an additional consequence that exported project size is larger by almost 1GB, but zip compressed project size is the same. Still, end user will download 1 GB more if I leave it as it is which is not good.

Upon checking further I realized VRAM compression creates duplicate files in .import folder, s3tc and etc2, and that files were created like this because this is how it is set by default in the Rendering/VRAM compression project settings.

I am exporting with S 3 TC Texture format enabled only, so this only adds to the confusion as why the additional 1 GB on export.

My questions is can I unpick any of those two formats ? I am using GLES3 and will export for Win and Linux. And even if I unpick one, would this even impact the export size ?

Not sure, any help appreciated.

:bust_in_silhouette: Reply From: Calinou

I am exporting with S 3 TC Texture format enabled only, so this only adds to the confusion as why the additional 1 GB on export.

VRAM compression has a fixed compression ratio (typically 1:4 or 1:6 depending on the format chosen). On the other hand, lossless PNG/WebP compression has a variable compression ratio. On simple artwork with few colors, this ratio can be 1:10 or even more.

Godot currently doesn’t support using lossless compression for VRAM-compressed files. There’s a pull request that implemented this feature, but it wasn’t merged due to lack of support. Also, note that using both VRAM compression and lossless compression will further slow down loading times, which are already quite slow when using large textures in Godot (due to the lack of texture streaming).

Also, remember that even if you used lossless + VRAM compression, this will not affect download size as your distribution medium will already perform lossless compression. It would only reduce installed size on disk, which isn’t as important on desktop platforms nowadays.

Hi, thank you for the answer.

One thing I want to clarify, my default project import setting for sprite textures was lossless. This option resulted in very bloated RAM usage. I have re-imported larger assets with VRAM compression and RAM went down a lot, and also the Steam download size went up for 1GB, everything else unchanged. So there has to be some misunderstanding somewhere.

AltoWaltz | 2021-11-01 14:06

Update2: Download size is unaffected, installed size on the disk is increased but also user gets prompted that the download size will be 1 GB larger that the actual download size, so that is where was the confusion.

Thank you for clarifying 1

AltoWaltz | 2021-11-04 12:59