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Bug Crunch compression not working on Lightmap file (2020.3.31f1)

Discussion in 'Global Illumination' started by roka, Mar 19, 2022.

  1. roka

    roka

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    Hello,

    I moved from Unity 2019.2.11f1 to 2020.3.31f1 and the Crunch compression is not working on the Lightmap file anymore. It's working on texture or sprite file but not on the Lightmap files.

    On 2019.2.11f1 everything work as expected.

    Did i missed something?

    Quick video :



    Thank you
     
  2. kristijonas_unity

    kristijonas_unity

    Unity Technologies

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    If this used to work, and now does not, then it is a serious regression. Once you'd have the time, could you please report a bug, and post the ID here afterwards. I will take a look at this myself.
     
    JamesArndt likes this.
  3. roka

    roka

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    Thank you.

    Case 1412758
     
    kristijonas_unity likes this.
  4. kristijonas_unity

    kristijonas_unity

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    Hello again. I took the time to investigate the issue, and have assigned it to texturing and streaming team. Hopefully, they will take a look at it soon.

    The reason why Crunch Compression is not working in newer Unity builds for WebGL, is due to a recent change in texture formats used by the WebGL platform. Prior to 2020.3, WebGL used DXT compression for both lightmap and directionality textures. In 2020.3, lightmap textures started using RGB9E, while directionality textures still used DXT compression. In 2021.2 editor versions and newer, lightmap textures now use BC6H compression. Both RGB9E and BC6H are not compatible with the Crunch Compression algorithm. Only DXT and ETC are.
     
  5. roka

    roka

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    Thank you for the update.

    I hope they have see the quality loss by using Crunched DXT1/DXT5 (even in windows/mac/linux) because it's impossible to use it with a quality like this. Only Compressed ASTC HDR 12x12 block look correct.
     
    Last edited: Mar 29, 2022
  6. roka

    roka

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    Hello, do you have any news on this issue? ( 1 month from now and the report is still at the same point ....)

    I have spend a lot of hours to figure out that since 2020.1.0f1 it's not working :

    No compressed



    The error when enabling webgl :



    Look the quality loss when we use crunched dxt5 (do not happen in 2019.x.x) :



    "Default" tab do not change the file size by using "use crunch compression"

    It's impossible to release something with that and it's funny that nobody have seen that they can't use crunched dxt5 with the lightmap file in the 2020.x.x ......

    The last version where it's working is Unity 2019.4.38f1.

    Thank you.
     
  7. kristijonas_unity

    kristijonas_unity

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    This issue is currently assigned to the texturing and streaming team. The team is evaluating whether or not it makes sense to hide the crunch compression option for unsupported formats. The underlying functionality is not likely to change.

    The tooltip already mentions that crunch compression only works wit DXT and ETC formats. If you do find that quality crunch compression quality has regressed when using identical settings on 2020.X when compared to older Unity versions, please submit another bug and we'll evaluate it.
     
  8. roka

    roka

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    There you go , Case 1422786
     
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  9. kristijonas_unity

    kristijonas_unity

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    roka likes this.
  10. kristijonas_unity

    kristijonas_unity

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  11. roka

    roka

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    @kristijonas_unity

    Sorry , but this issue is still present in :

    - Unity 2021.3.15f1
    - Unity 2022.2.1f1

    As you can see in the video below, trying "Use Crunch Compression" in the default tab do not change the file size and by using the "Override For WebGL" tab, the size is not correct or we get a bad quality result.

    Only happen with lightmap file, not texture file.

    Video using Unity 2022.2.1f1:

     
  12. roka

    roka

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    Last edited: Jan 22, 2023