feat: implement continuous mode

[Murmele]

This PR is far away from being finished, but maybe someone can have a look on it and provide feedback.
Implement continuous mode with map and renderer observer.

Not working

• setSize still crashes Doesn't crash, but resize does not work yet (Fix Vulkan headless backend resize maplibre-native#4030)
• renderer observer callback gets never called Not required anymore, because only MapObserver is used

Testing

Currently I am testing it in my project with Slint: https://gitlab.com/Murmele/slintmaplibretest

Launch Checklist

• Confirm your changes do not include backports from Mapbox projects (unless with compliant license) - if you are not sure about this, please ask!
• Briefly describe the changes in this PR.
• Link to related issues.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality.
• Document any changes to public APIs.
• Post benchmark scores.
• Add an entry to CHANGELOG.md under the ## main section.

[nyurik]

hi @Murmele thx for all the hard work on this!!! Please join us in https://slack.openstreetmap.us/ on slack - this way you can chat directly with all of us and we can collaborate better. Let me know if you need any help.

[nyurik]

@mwilsnd for some reason I cannot add you to the reviewers, but your feedback would be great!

[Murmele]

hi @Murmele thx for all the hard work on this!!! Please join us in https://slack.openstreetmap.us/ on slack - this way you can chat directly with all of us and we can collaborate better. Let me know if you need any help.

Thanks for the invitation! Is there a channel related to maplibre or just the general?

[nyurik]

#maplibre-native and #maplibre are probably the most relevant

[mwilsnd]

Looking at how the allocation size is determined in native here, this should just be 4 * width * height. Are you seeing a bounds check or alignment failure unless you allocate extra space?

[mwilsnd]

Currently setSize does not work. I have seen in the vulkan/headless_backend That the size is only used the first time the texture got created.

@mwilsnd shouldn't the texture recreated once the size changes?

If you try to resize the frontend two or more times before calling readStillImage, do you get a properly sized output? Looks like the OpenGL backend should also work, but the vulkan implementation linked does look like it needs to be updated to handle size changes.

[Murmele]

Currently setSize does not work. I have seen in the vulkan/headless_backend That the size is only used the first time the texture got created.
@mwilsnd shouldn't the texture recreated once the size changes?

If you try to resize the frontend two or more times before calling readStillImage, do you get a properly sized output? Looks like the OpenGL backend should also work, but the vulkan implementation linked does look like it needs to be updated to handle size changes.

Yes maybe this is missing: maplibre/maplibre-native#4030

[Murmele]

I will check it out next weeks to get it build again

[nyurik]

thanks!!! I have been using github's copilot quiet successfully - the only problem with it is that it doesn't work across forks :( I'll see if i can just create an extra issue and assign it - maybe it will self-heal

[nyurik]

I created #129 - will see what copilot does :)

[nyurik]

horray, this PR passes once again. What the status of it? I would looooove to have this as part of mln-rs :)

[Murmele]

horray, this PR passes once again. What the status of it? I would looooove to have this as part of mln-rs :)

The PR passes, but in my testapplication it does not compile anymore because of missing libraries in the almagan (was it the mln texture?). I hope I get it this week up :)