Struct MeshEncoder 

pub struct MeshEncoder { /* private fields */ }

Available on crate feature encoder only.

Encoder for Draco triangle mesh bitstreams.

A MeshEncoder takes a Mesh plus EncoderOptions and writes a self-contained .drc bitstream (header, optional metadata, connectivity, and attributes) into an EncoderBuffer. The encoding method (EdgeBreaker or sequential), prediction schemes, and quantization are selected from the options, mirroring the C++ MeshEncoder/ExpertEncoder configuration.

encode produces the bitstream and nothing else. A caller who also wants per-attribute and per-face details of what the encode did uses encode_with_info, which derives them; they are not a byproduct of encoding and are not computed for callers who do not ask.

Examples

Build a single-triangle mesh, encode it, and decode it back:

use draco_core::{
    DataType, DecoderBuffer, EncoderBuffer, EncoderOptions, FaceIndex,
    GeometryAttributeType, Mesh, MeshDecoder, MeshEncoder, PointAttribute,
};

// One triangle with a float32 position attribute (3 vertices).
let mut mesh = Mesh::new();
let mut position = PointAttribute::new();
position.init(GeometryAttributeType::Position, 3, DataType::Float32, false, 3);
let coords: [f32; 9] = [0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0];
for (i, value) in coords.iter().enumerate() {
    position.buffer_mut().write(i * 4, &value.to_le_bytes());
}
mesh.add_attribute(position);
mesh.set_num_faces(1);
mesh.set_face(FaceIndex(0), [0u32.into(), 1u32.into(), 2u32.into()]);

// Encode to a Draco bitstream.
let mut encoder = MeshEncoder::new();
encoder.set_mesh(mesh);
let mut buffer = EncoderBuffer::new();
encoder.encode(&EncoderOptions::new(), &mut buffer)?;

// Decode it back.
let mut decoded = Mesh::new();
MeshDecoder::new().decode(&mut DecoderBuffer::new(buffer.data()), &mut decoded)?;
assert_eq!(decoded.num_faces(), 1);

Implementations

impl MeshEncoder

pub fn new() -> Self

Creates an encoder without an assigned mesh.

pub fn set_mesh(&mut self, mesh: Mesh)

Assigns the mesh to encode.

pub fn mesh(&self) -> Option<&Mesh>

Returns the assigned mesh, if any.

pub fn num_encoded_faces(&self) -> usize

Returns the number of faces encoded by the last successful encode.

pub fn corner_table(&self) -> Option<&CornerTable>

Returns the corner table built during the last mesh encode, if any.

pub fn encode( &mut self, options: &EncoderOptions, out_buffer: &mut EncoderBuffer, ) -> Status

Encodes the assigned mesh into an output buffer.

A mesh must have been provided with set_mesh first. On success the bitstream is appended to out_buffer and nothing else is computed; use encode_with_info to also get a description of the encode.

Errors

Returns an error if no mesh was set, if the requested encoding method or options are unsupported, or if attribute encoding fails.

pub fn encode_with_info( &mut self, options: &EncoderOptions, out_buffer: &mut EncoderBuffer, ) -> Result<EncodedMeshInfo, DracoError>

Encodes the assigned mesh and describes what the encode did.

The description is derived from the encode rather than produced by it, and deriving it costs a sweep of every position for its bounds plus a copy of the encoded point order per attribute. So it is the caller who decides whether that work happens: encode never does it, and this does it exactly once, here, where it was asked for.

Errors

The same errors as encode, plus a failure to derive the description. The bitstream in out_buffer is complete and valid in that last case; only the description is missing.

Trait Implementations

impl Default for MeshEncoder

fn default() -> Self

Returns the “default value” for a type.

impl GeometryEncoder for MeshEncoder

fn point_cloud(&self) -> Option<&PointCloud>

Returns point-cloud geometry when available.

fn mesh(&self) -> Option<&Mesh>

Returns mesh geometry when available.

fn corner_table(&self) -> Option<&CornerTable>

Returns mesh corner-table topology when available.

fn options(&self) -> &EncoderOptions

Returns the active encoder options.

fn get_geometry_type(&self) -> EncodedGeometryType

Returns the encoded geometry type.

fn get_encoding_method(&self) -> Option<i32>

Returns the forced encoding method, if one is active.

fn get_data_to_corner_map(&self) -> Option<&[u32]>

Returns a data-to-corner map for mesh attribute prediction, if present.

fn get_vertex_to_data_map(&self) -> Option<&[i32]>

Returns a vertex-to-data map for mesh attribute prediction, if present.

fn get_portable_attribute(&self, att_id: i32) -> Option<&PointAttribute>

Returns the portable (quantized) form of an attribute, once the encoder has transformed it. Prediction schemes that read a parent attribute – tex coords and geometric normals both predict from the position – must use this and not the original floats, because the decoder only ever has the portable values to predict from. Counterpart of C++ PointCloudEncoder::GetPortableAttribute.