GizmoGeometry

Remarks

The other half of TransformGizmo, kept apart from it on purpose. The gizmo decides where the handles are, what is under the pointer and what a drag means, and all of that is testable with no device. This turns the same numbers into geometry, and it is separate so that changing how a gizmo looks cannot change what it does.

⚠ The arms are built from the same WorldPerPixel and the same basis the hit test uses. Not similar arithmetic — the same calls. A gizmo drawn a little larger than it is hit-tested is one where the last few pixels of every arm do nothing, which reads as the tool being unreliable rather than as an arithmetic difference.

⚠ A thick line is several thin ones, and it has to be. LineRenderer draws one-pixel lines and deliberately refuses to offer anything else: lineWidth above one is an optional Vulkan feature that most tiled GPUs lack, so a renderer that offered it would draw a different picture on different machines. Its own remarks say a thick line belongs to whoever wants one — this is that. Every segment is emitted Thickness times, each shifted a pixel further across the segment on screen, which is the only offset that thickens a line rather than smearing it along itself or into the depth buffer.

Lines rather than solid cones and rings, which is what a shipping gizmo eventually wants. A line renderer exists and a mesh path for the editor does not, and an editor whose handles are visible now is worth more than one whose handles are beautiful later.

Fields and properties (8)

• public const int RingSegments

  How many segments a rotation ring is drawn with.

• public const float HighlightShade

  How much of its colour a handle keeps while the pointer is over it.

• public const float Ambient

  How much light a surface facing away from the key still receives.

• public const float PlaneFillAlpha

  How translucent a plane handle's fill is when it is not under the pointer.

• public const float PlaneHighlightAlpha

  And when it is.

• public const float PlaneEdgeOn

  How nearly edge-on a plane handle may be before it is neither drawn nor grabbable.

• public const int TubeSides

  How many sides a rotation ring's tube has.

• public const int HeadSegments

  How many divisions a solid head is built with.

Methods (7)

• public static Vector3 TowardsEye(EditorCamera camera, Vector3 origin)

  Which way the eye is from a point, for deciding what faces it.

• public static Color4 AxisColour(int axis, bool highlighted = false)

  The colour of the arm along an axis.

• public static Color4 NeutralColour(bool highlighted = false)

  The colour of a handle that belongs to no axis: the middle ball, the screen ring.

• public static Vector3 KeyLight(EditorCamera camera)

  Which way the light a handle is shaded by travels.

• public static float Shade(Vector3 normal, Vector3 light)

  How brightly a surface facing some way is lit, from Ambient to one.

• public static int Build(TransformGizmo gizmo, EditorCamera camera, int height, List<LineVertex> into)

  Builds the handles for a gizmo as it currently stands.

• public static int BuildSolid(TransformGizmo gizmo, EditorCamera camera, int height, List<MeshVertex> vertices, List<uint> triangles)

  Builds the solid parts of a gizmo: the head on the end of each arm.

Used by (5)

• GizmoGeometryTestsVixen.Editor.SceneView.Tests
• ManipulationTestsVixen.Editor.SceneView.Tests
• SceneLinesVixen.Editor.SceneView
• ScenePresenterVixen.Editor.App
• TransformGizmoVixen.Editor.SceneView