MeshData class Geometry

An isolate-transferable snapshot of a mesh's vertex and index data.

MeshData separates the CPU work of building a mesh (assembling vertex arrays and generating normals) from the GPU upload. Its construction is pure and touches no GPU resources, so it can run on a background isolate; the result is sent back and turned into a live mesh on the render isolate. This keeps heavy meshing, such as remeshing a voxel chunk, off the render isolate.

It is also the interchange type for reading geometry back and deriving new geometry from it: Geometry.extractMeshData produces one from a loaded mesh, and the pure derivation methods (unweld, extractEdges, merge) consume and produce them, so a whole derivation chain can run off the render isolate.

Recipe (using compute from package:flutter/foundation.dart):

// Top-level or static, runs on the background isolate.
MeshData buildChunk(ChunkInput input) {
  final positions = ...; // your generator
  final indices = ...;
  return MeshData.build(positions: positions, indices: indices);
}

// On the render isolate:
final data = await compute(buildChunk, input);
final geometry = MeshGeometry.fromMeshData(data);
// or, to update an existing updatable mesh in place:
existing.applyMeshData(data);

Constructors

MeshData({required Float32List positions, required int vertexCount, Float32List? normals, Float32List? texCoords, Float32List? colors, List<int>? indices, PrimitiveType primitiveType = gpu.PrimitiveType.triangle, Map<String, MeshAttributeData> customAttributes = const {}})

Wraps already-prepared vertex arrays without generating anything.

MeshData.build({required Float32List positions, Float32List? normals, Float32List? texCoords, Float32List? colors, List<int>? indices, PrimitiveType primitiveType = gpu.PrimitiveType.triangle, Map<String, MeshAttributeData> customAttributes = const {}})

Builds a snapshot from vertex attribute arrays, generating area-weighted normals from the faces when normals is absent and primitiveType is a triangle list. The normal generation is the work worth doing off the render isolate. The attribute-array contract matches MeshGeometry.fromArrays.

factory

Properties

colors → Float32List?

Vertex colors (four floats each), or null to default to opaque white.

final

customAttributes → Map<String, MeshAttributeData>

Named custom per-vertex attribute streams, forwarded to Geometry.setCustomAttribute on upload.

final

hashCode → int

The hash code for this object.

no setter, inherited

indices → List<int>?

Triangle (or line/point) indices, or null for a non-indexed mesh.

final

normals → Float32List?

Vertex normals (three floats each), or null to let the upload generate or default them.

final

positions → Float32List

Vertex positions, three floats each.

final

primitiveType → PrimitiveType

How the vertices assemble into primitives when drawn.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

texCoords → Float32List?

Texture coordinates (two floats each), or null to default to (0, 0).

final

triangleCount → int

The number of triangles (indexed or not). Zero for non-triangle primitive types.

no setter

triangles → Iterable<MeshTriangle>

Iterates the mesh's triangles with their corner indices and positions.

no setter

vertexCount → int

The number of vertices, equal to positions.length ~/ 3.

final

Methods

extractEdges({double? creaseAngleDegrees}) → LineSegmentData

The mesh's unique undirected edges as disconnected line segments.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

unweld({Set<UnweldAttribute> attributes = const {}}) → MeshData

A flat-shaded triangle soup derived from this mesh.

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

merge(List<MeshData> parts) → MeshData

Concatenates parts into one snapshot, rebasing indices.