Struct VolumeItem 

#[non_exhaustive]
pub struct VolumeItem {

    pub volume_id: VolumeId,
    pub pick_id: u64,
    pub volume_data: Option<Arc<VolumeData>>,
    pub colour_lut: Option<ColourmapId>,
    pub opacity_lut: Option<ColourmapId>,
    pub scalar_range: (f32, f32),
    pub bbox_min: [f32; 3],
    pub bbox_max: [f32; 3],
    pub step_scale: f32,
    pub model: [[f32; 4]; 4],
    pub enable_shading: bool,
    pub opacity_scale: f32,
    pub threshold_min: f32,
    pub threshold_max: f32,
    pub nan_colour: Option<[f32; 4]>,
    pub appearance: AppearanceSettings,
    pub selected: bool,
}

A volume item to render via GPU ray-marching.

The caller uploads a 3D scalar field via ViewportGpuResources::upload_volume and receives a VolumeId. Each frame, submit a VolumeItem referencing that id plus transfer function and display parameters.

Picking

Set pick_id to a non-zero value and provide volume_data to enable voxel-level picking via renderer.pick() and renderer.pick_rect(). pick_id is the ID returned in the PickHit when a voxel is hit. A pick_id of zero means the volume is not pickable. volume_data must match the data that was passed to upload_volume for this volume_id.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

volume_id: VolumeId

Reference to a previously uploaded 3D texture.

pick_id: u64

Pick ID returned when a voxel in this volume is hit.

0 means this volume is not pickable. Set to a non-zero value alongside volume_data to enable voxel picking.

volume_data: Option<Arc<VolumeData>>

CPU scalar data for voxel picking.

Must match the data passed to upload_volume for volume_id. None disables voxel-level picking regardless of pick_id.

colour_lut: Option<ColourmapId>

Colour transfer function LUT. None = use default builtin (viridis).

opacity_lut: Option<ColourmapId>

Opacity transfer function LUT. None = linear ramp (0 at min, 1 at max).

scalar_range: (f32, f32)

Scalar range for normalization [min, max].

bbox_min: [f32; 3]

World-space bounding box minimum corner.

bbox_max: [f32; 3]

World-space bounding box maximum corner.

step_scale: f32

Ray step multiplier. Lower = higher quality, slower. Default: 1.0.

model: [[f32; 4]; 4]

World-space transform. Default: identity.

enable_shading: bool

Whether to apply gradient-based Phong shading. Default: false.

opacity_scale: f32

Global opacity multiplier. Default: 1.0.

threshold_min: f32

Scalar threshold range [min, max]. Samples outside this range are discarded (opacity = 0). Default: same as scalar_range (no clipping).

threshold_max: f32

Upper scalar threshold. Samples above this value are discarded. Default: same as scalar_range.1 (no clipping).

nan_colour: Option<[f32; 4]>

Colour and opacity to use for NaN scalar samples. None = skip NaN samples entirely (same as current behaviour: discard). Some([r, g, b, a]) = render NaN voxels with this fixed RGBA colour instead of sampling the transfer function.

appearance: AppearanceSettings

Per-item appearance overrides (hidden, unlit, opacity, wireframe).

selected: bool

When true, the renderer draws a wireframe outline around the volume AABB. Default: false.

Trait Implementations

impl Clone for VolumeItem

fn clone(&self) -> VolumeItem

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for VolumeItem

fn default() -> Self

Returns the “default value” for a type.