World grid part 2/2: Integrate into Viewer

[Wumpf]

Related

• Follow-up of part 1: World grid part 1/2: add world grid renderer to re_renderer #8230
• Fixes World-space grid #872

What

Adds new line grid property to the 3D view and enables it by default.

Furthermore...

• improves the grid shader with infinite cardinal lines while showing only two types of "cardinalitities"
  • this is simply based on log10(camera distance from plane) and then blends between two levels of grid
• improve grid's handling of extreme zoom levels. Still some instability on WebGL, but overall much more robust (less flickering/cutoff)
• Introduce a general Plane3D component which is meant for later reuse in other contexts

The new view property is best described its fbs:

/// Configuration for the 3D line grid.
table LineGrid3D (
    "attr.rerun.scope": "blueprint"
) {
    /// Whether the grid is visible.
    ///
    /// Defaults to true.
    visible: rerun.blueprint.components.Visible ("attr.rerun.component_optional", nullable, order: 1000);

    /// Space between grid lines spacing of one line to the next in scene units.
    ///
    /// As you zoom out, successively only every tenth line is shown.
    /// This controls the closest zoom level.
    spacing: rerun.blueprint.components.GridSpacing ("attr.rerun.component_optional", nullable, order: 2000);

    /// In what plane the grid is drawn.
    ///
    /// Defaults to whatever plane is determined as the plane at zero units up/down as defined by [components.ViewCoordinates] if present.
    plane: rerun.components.Plane3D ("attr.rerun.component_optional", nullable, order: 3000);

    /// How thick the lines should be in ui units.
    ///
    /// Default is 1.0 ui unit.
    stroke_width: rerun.components.StrokeWidth ("attr.rerun.component_optional", nullable, order: 5000);

    /// Color used for the grid.
    ///
    /// Transparency via alpha channel is supported.
    /// Defaults to a slightly transparent light gray.
    color: rerun.components.Color ("attr.rerun.component_optional", nullable, order: 6000);
}

Properties in the viewer in default selection panel width

New plane controls expanded:

Examples of the grid in action (in default settings):

Bad case - grid is not fine enough and through the scene:

Bad case - grid is above the scene.

Testing

• Metal
• Vulkan
• WebGPU
• WebGL

Future work

• tweak some examples to disable the grid or change its spacing
• Extend grid to 2d scenes

[github-actions]

Latest documentation preview deployed successfully.

Result	Commit	Link
✅	5fe5dfd	https://landing-nuo6pcdya-rerun.vercel.app/docs

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[github-actions]

Web viewer built successfully. If applicable, you should also test it:

• I have tested the web viewer

Result	Commit	Link
✅	5fe5dfd	https://rerun.io/viewer/pr/8234

^{Note: This comment is updated whenever you push a commit.}

[nikolausWest]

Small bug: it's now possible to set alpha in the color picker for the Lines3D override (which obviously doesn't work)

[nikolausWest]

Just clicking through some examples it's clear that the grid doesn't end up at the "right" height for most of them. Wonder if it's worth explicitly settign the plane height to make those look good?

[Wumpf]

yes, we should likely do some adjustments there on a per example basis. For some examples we may also want to turn it off

[abey79]

Awesome!

[abey79]

Note: another short term quick win by rolling tagged component to view property. We could make the component ui editor white list some Archetype/Field for the transparency ui.