Struct LineProbeWidget 

pub struct LineProbeWidget {
    pub start: Vec3,
    pub end: Vec3,
    pub colour: [f32; 4],
    pub line_width: f32,
    pub handle_colour: [f32; 4],
    /* private fields */
}

A two-endpoint line handle rendered in the viewport.

Drag either sphere handle to reposition the probe path. Read start and end each frame to get the current endpoint positions.

Usage

// Setup (once):
let mut probe = LineProbeWidget::new(
    glam::Vec3::new(-2.0, 0.0, 0.0),
    glam::Vec3::new( 2.0, 0.0, 0.0),
);

// Each frame:
let ctx = WidgetContext { camera, viewport_size, cursor_viewport,
                          drag_started, dragging, released };
probe.update(&ctx);

fd.scene.polylines.push(probe.polyline_item(LINE_ID));
fd.scene.glyphs.push(probe.handle_glyphs(HANDLE_ID_BASE, &ctx));

// Suppress orbit while dragging:
if probe.is_active() { orbit.resolve(); } else { orbit.apply_to_camera(&mut camera); }

Fields

start: Vec3

World-space position of the first endpoint.

end: Vec3

World-space position of the second endpoint.

colour: [f32; 4]

RGBA line and handle colour.

line_width: f32

Line width in pixels.

handle_colour: [f32; 4]

RGBA colour for the drag handles. When set (non-zero alpha), overrides the default LUT colouring.

Implementations

impl LineProbeWidget

pub fn new(start: Vec3, end: Vec3) -> Self

Create a new probe between two world-space positions.

pub fn hovered_endpoint(&self) -> Option<usize>

Index of the currently hovered endpoint (0 = start, 1 = end).

pub fn is_active(&self) -> bool

True while a drag session is in progress on either endpoint.

pub fn update(&mut self, ctx: &WidgetContext) -> WidgetResult

Process input for this frame. Returns Updated if either endpoint moved.

Call once per frame before building render items.

pub fn polyline_item(&self, id: u64) -> PolylineItem

Build the PolylineItem for the line segment between the two endpoints.

id is used as the pick ID for the line body (0 = not pickable).

pub fn handle_glyphs(&self, id_base: u64, ctx: &WidgetContext) -> GlyphItem

Build a GlyphItem containing sphere handles at both endpoints.

Handle size is constant in screen space (approximately 10 px radius). id_base is the pick ID for the start handle; the end handle uses id_base + 1.

Colour is driven by the colourmap (viridis by default). The scalar for each handle is 0.0 when idle and 1.0 when hovered or active, so the two states map to distinct colourmap colours.