Struct GridTransform 

pub struct GridTransform {
    pub origin: DVec3,
    pub rotation: DQuat,
}

f64 world placement of one grid: position + orientation.

origin is the grid’s local-space origin in world coords — chunk (0, 0, 0)’s (0, 0, 0) voxel maps to origin + rotation * vec3(0, 0, 0) (i.e. just origin). Voxel size is fixed at 1 world unit / voxel for v1.

Fields

origin: DVec3

The grid’s local-space origin, in world coordinates.

rotation: DQuat

The grid’s orientation about origin.

Implementations

impl GridTransform

pub fn identity() -> Self

Identity transform at world origin. Useful as a default for the first grid added to an otherwise empty scene.

Examples found in repository

examples/book_controller.rs (line 31)

fn build_world() -> Scene {
    let mut scene = Scene::new();
    let id = scene.add_grid(GridTransform::identity());
    let g = scene.grid_mut(id).expect("grid");
    // Ground slab: surface plane at z = 100 (+z is down, so the
    // slab fills downward).
    g.set_rect(
        IVec3::new(20, 20, 100),
        IVec3::new(140, 140, 120),
        Some(VoxColor::rgb(0x4d, 0x8a, 0x3a)),
    );
    // A 1-voxel ledge to step onto, and a wall to slide along.
    g.set_rect(
        IVec3::new(90, 20, 99),
        IVec3::new(140, 140, 99),
        Some(VoxColor::rgb(0x77, 0x66, 0x55)),
    );
    g.set_rect(
        IVec3::new(60, 70, 60),
        IVec3::new(62, 140, 99),
        Some(VoxColor::rgb(0x88, 0x44, 0x44)),
    );
    // A water curtain the veto lets the body wade through. Two
    // format facts (both pinned as engine tests): pass-through
    // geometry works up to 2 voxels thick — thicker walls grow a
    // colourless UnexposedSolid core no veto can classify — and
    // must sit ≥ 1 voxel inside the chunk (edge voxels lose their
    // side colours).
    g.set_rect(IVec3::new(40, 40, 80), IVec3::new(41, 60, 99), Some(WATER));
    scene
}

pub fn at(origin: DVec3) -> Self

Axis-aligned grid placed at origin with no rotation.

Examples found in repository

examples/book_scene_graph.rs (line 87)

fn main() {
    // ANCHOR: scene_grids
    let mut scene = Scene::new();
    // A static "world" grid at the origin…
    let ground_id = scene.add_grid(GridTransform::at(DVec3::ZERO));
    // …and a second grid placed and rotated independently — its own
    // f64 world position + quaternion, same chunked voxel payload.
    let ship_id = scene.add_grid(GridTransform {
        origin: DVec3::new(300.0, -80.0, -40.0),
        rotation: DQuat::from_rotation_z(0.5),
    });
    // Object grids should not paint their own (grid-local, rotating)
    // sky — leave the sky to the world grid.
    scene.grid_mut(ship_id).expect("just added").render_sky = false;
    // ANCHOR_END: scene_grids

    // ANCHOR: edits
    let ground = scene.grid_mut(ground_id).expect("just added");
    // Solid slab: grid-local voxel coords, inclusive on both ends,
    // decomposed across as many chunks as it spans (here 4×4).
    ground.set_rect(
        IVec3::new(-200, -200, 200),
        IVec3::new(199, 199, 254),
        Some(GRASS),
    );
    // `Some(colour)` inserts, `None` carves back to air.
    ground.set_sphere(IVec3::new(0, 0, 195), 12, Some(STONE));
    ground.set_rect(IVec3::new(-3, -200, 190), IVec3::new(3, 199, 196), None);
    // ANCHOR_END: edits

    // ANCHOR: queries
    // Solid tests: inside the slab, then inside the carved tunnel.
    assert!(ground.voxel_solid(IVec3::new(0, 0, 210)));
    assert!(!ground.voxel_solid(IVec3::new(0, 100, 193)));
    // Colour queries answer on surface voxels; deep interior cells
    // are untextured in the slab format and read as `None`.
    assert_eq!(ground.voxel_color(IVec3::new(50, 50, 200)), Some(GRASS));
    // ANCHOR_END: queries

    // ANCHOR: recolour
    // GOTCHA: inserting over already-solid voxels does NOT repaint
    // them — span insertion only fills air. Recolour = carve, then
    // insert.
    let (lo, hi) = (IVec3::new(20, 20, 200), IVec3::new(24, 24, 204));
    ground.set_rect(lo, hi, Some(RED));
    assert_eq!(ground.voxel_color(IVec3::new(22, 22, 200)), Some(GRASS)); // unchanged!
    ground.set_rect(lo, hi, None); // carve…
    ground.set_rect(lo, hi, Some(RED)); // …then insert
    assert_eq!(ground.voxel_color(IVec3::new(22, 22, 200)), Some(RED));
    // ANCHOR_END: recolour

    // ANCHOR: colfunc
    // A carve exposes fresh interior walls; the plain edits paint
    // them colour 0 (black). The `_with_colfunc` variants ask a
    // closure instead — it sees grid-local coordinates, so gradients
    // stay continuous across chunk seams. Here: a crater whose walls
    // darken with depth.
    ground.set_sphere_with_colfunc(IVec3::new(60, 60, 200), 8, SpanOp::Carve, |_x, _y, z| {
        let depth = (z - 192).clamp(0, 15) as u8;
        VoxColor::rgb(0x6b, 0x40 + depth * 3, 0x2f)
    });
    // ANCHOR_END: colfunc

    // ANCHOR: snapshot
    // Name grids before saving: ids survive the round-trip, but the
    // generator / store hooks are host code and cannot be serialised
    // — the name is your key for rebinding them after a load.
    scene.grid_mut(ground_id).expect("ground exists").name = Some("ground".into());
    let bytes = scene.save_snapshot(); // versioned envelope
    let restored = Scene::load_snapshot(&bytes).expect("self-authored snapshot");
    assert_eq!(restored.grid_count(), 2);
    let (_, ground2) = restored
        .grids()
        .find(|(_, g)| g.name.as_deref() == Some("ground"))
        .expect("rebind by name");
    assert_eq!(ground2.voxel_color(IVec3::new(22, 22, 200)), Some(RED));
    // ANCHOR_END: snapshot

    // ANCHOR: streaming
    // Streaming: attach a generator + radii to a grid, then pump once
    // per frame with the camera's world position. Chunks within
    // `r_active` stream in; chunks beyond `r_evict` drop out; the band
    // between is hysteresis so a camera hovering on a boundary
    // doesn't thrash.
    let stream_id = scene.add_grid(GridTransform::at(DVec3::new(0.0, 4096.0, 0.0)));
    let store = Arc::new(MemoryStore::default());
    let grid = scene.grid_mut(stream_id).expect("just added");
    grid.set_generator(Some(Arc::new(FloorGenerator)));
    grid.set_chunk_store(Some(store));
    grid.stream_radius = StreamRadius::new(256.0, 384.0);

    let camera_near = DVec3::new(0.0, 4096.0, 100.0);
    scene.pump_streaming_sync(camera_near); // real games: `pump_streaming`
    let grid = scene.grid(stream_id).expect("still there");
    assert!(grid.chunk_count() > 0); // floor streamed in around the camera
    assert!(grid.voxel_solid(IVec3::new(5, 5, 240)));
    // ANCHOR_END: streaming

    // ANCHOR: streaming_edit
    // Edit the streamed floor, walk far away, come back. The active
    // set follows the camera: the old region evicts (edited chunks
    // are handed to the ChunkStore first) while a fresh set streams
    // in around the new position. On return the store wins over the
    // generator, so the edit survives; without a store, eviction
    // would silently revert the chunk to generator output.
    scene
        .grid_mut(stream_id)
        .expect("still there")
        .set_voxel(IVec3::new(5, 5, 240), None); // dig a hole
    scene.pump_streaming_sync(camera_near + DVec3::new(0.0, 100_000.0, 0.0));
    let grid = scene.grid(stream_id).expect("still there");
    assert!(grid.chunk(IVec3::ZERO).is_none()); // home chunk evicted…
    assert!(grid.chunk_count() > 0); // …but the far region streamed in
    scene.pump_streaming_sync(camera_near);
    let grid = scene.grid(stream_id).expect("re-streamed");
    // The hole survived evict + re-stream.
    assert!(!grid.voxel_solid(IVec3::new(5, 5, 240)));
    // ANCHOR_END: streaming_edit

    println!("book_scene_graph: all scene-graph assertions hold");
}

Trait Implementations

impl Clone for GridTransform

fn clone(&self) -> GridTransform

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for GridTransform

impl Debug for GridTransform

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for GridTransform

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for GridTransform

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for GridTransform

fn eq(&self, other: &GridTransform) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for GridTransform

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for GridTransform