Fix disappearing of MyLocation point

[glughi]

What this PR does

Fixes #7725

Checklist

• There are unit tests to verify my changes are correct or unit tests aren't applicable (if so, write quick reason why unit tests don't exist)
• I've updated relevant documentation in doc/.
• I've updated CHANGES.md with what I changed.
• I've provided instructions in the PR description on how to test this PR.

[glughi]

Hello, any news about this PR?

[niktayv]

Hi Giovanni. Thanks for the fix and for your interest in improving TerriaJS.
I tested your solution locally, and it does resolve the issue.

Can I suggest you tweak the implementation to be a bit more robust and generic?

As far as I understand your idea, we want the app-generated "My Location" item to remain visible, even when the "Terrain hides underground features" checkbox is enabled. Your solution works, but it creates a coupling to i18n and to a very concrete instance of the item, which may be a leaky abstraction.

Add a generic trait isAlwaysVisible?: boolean = false to lib/Traits/TraitsClasses/GeoJsonTraits.ts with a description for disabling depth testing.

@primitiveTrait({
  type: "boolean",
  name: "Is Always Visible",
  description:
    "If true, points will render without depth testing so they remain visible through terrain and tiles."
})
isAlwaysVisible?: boolean = false;

Set this trait on the app-created My Location marker in lib/ReactViews/Map/MapNavigation/Items/MyLocation.ts:

this._marker.setTrait(CommonStrata.user, "isAlwaysVisible", true);

In lib/ModelMixins/GeojsonMixin.ts, switch the depth-test override to:

disableDepthTestDistance: this.isAlwaysVisible
  ? new ConstantProperty(Number.POSITIVE_INFINITY)
  : undefined

Hopefully, this will be closer to TerriaJS’s architecture (avoiding name/i18n coupling and making the behaviour reusable).

[na9da]

I agree with @niktayv's comment on moving the setting to somewhere that is more specific.

This could be done in MyLocation.ts where the marker is created, by adding something like below:

// Set depth test distance to a large value to disable it so that the marker is visible even when dept testing is enabled
this._marker.defaultStyle.point.null.setTrait(CommonStrata.user, "disableDepthTestDistance", 9999999);

This is using the existing disableDepthTestDistance trait (which is honestly a bit hard to find)

[glughi]

Hi @na9da, I tried the suggestion (and some variations), but it doesn't seem to work to fix the issue.

[na9da]

Ah sorry! That's because when using simple-style for GeoJSON these other styling traits (like disableDepthTestDistance) are ignored.

In that case I would use what @niktayv has suggested - to add a new trait and set that from MyLocation.ts - but maybe name the new boolean trait disableDepthTest instead of isAlwaysVisible to make it a bit more obvious.

[niktayv]

LGTM

[na9da]

LGTM. Thanks @glughi @niktayv