Module mesh 

Vertex compression and the per-mesh decode metadata.

The built-in pipeline consumes a compact vertex layout: positions and UVs are 16-bit normalized integers relative to a per-mesh bounding box, so the shader needs the parameters that reverse that encoding. MeshMetadata carries those parameters; compress_positions and compress_uvs produce them together with the packed attribute streams.

The Rust side and the WGSL side (mesh_metadata.wesl) are kept in sync by the crate. SecondaryStreamWriter and PositionStreamWriter pack the per-vertex streams a draw declares, whichever pipeline then draws them.

One description per stream

A stream is described by StreamChannels: one attribute location and ChannelEncoding per channel, in the order the channels are interleaved. The pipeline’s vertex layout, the compression that packs a mesh and the streams a pool allocates all derive their bytes per vertex from that same description, so the three cannot drift apart.

Re-exports

use wgpu::WriteOnly; 🔒

Structs

JointPair

The joint indices and weights of one vertex, as the position stream stores them.

MeshInstance

One per-instance record: the affine model matrix, base color, pose bases, metadata index, alpha cutoff and inverted-hull width the built-in pipeline reads from its per-instance vertex buffer.

MeshMetadata

Per-mesh vertex-decode parameters and draw addressing.

PositionStreamChannels

The channels of the position vertex stream: a position and, for a skinned mesh, the joint indices and weights that deform it.

PositionStreamWriter

Packs the position vertex stream: the compressed position and, when the stream declares them, the joint indices and weights that deform it.

SecondaryFlags

The optional per-vertex channels of a secondary vertex stream: the UV, color and normal a mesh carries beside its position.

SecondaryStreamWriter

The optional per-vertex channels of a secondary vertex stream: the UV, color and normal that a mesh carries beside its position.

StreamChannels

The channels one per-vertex stream carries, in the order they are interleaved.

Enums

ChannelEncoding

How one compressed channel is encoded as a vertex attribute.

CompressError

Failure reasons reported by the compression helpers.

Constants

MAX_POSITION_STRIDE 🔒

Bytes per vertex of the widest position stream, used to size the per-vertex scratch the writer assembles on the stack.

MAX_SECONDARY_STRIDE 🔒

Bytes per vertex of the widest secondary stream, used to size the per-vertex scratch the writer assembles on the stack.

Functions

compress_indices

Narrow u32 indices to u16.

compress_normals

Octahedral-encode normals into Snorm16x2 lanes.

compress_positions

Compress positions into Snorm16x4 relative to their bounding box, writing the decode parameters into out_meta.

compress_uvs

Compress UVs into Snorm16x2 remapped by their bounding box, writing the decode parameters into out_meta.uv_min_and_extents.

compress_weights

Quantize joint weights to Unorm16x4, clamping out-of-range components.

derive_position_bounds 🔒

Derive the position decode parameters from positions and write them into out_meta.

derive_uv_bounds 🔒

Derive the UV decode parameters from uvs and write them into out_meta.uv_min_and_extents.

encode_scale 🔒

The reciprocal of extents, with degenerate axes collapsed to zero.

encode_scale2 🔒

The 2D counterpart of encode_scale, for the UV range.

encode_uvs

The compressed UVs of uvs, encoded against out_meta’s existing parameters without re-deriving them.

f32_to_snorm16 🔒

Quantize [-1, 1] floats to signed 16-bit normalized integers.

f32_to_unorm8 🔒

Quantize one normalized f32 to Unorm8.

f32_to_unorm16 🔒

Quantize one normalized f32 to Unorm16.

index_fits_u16

Whether a vertex index can be named by a Uint16 index buffer.

octahedral_encode 🔒

Octahedral-encode a unit normal into two [-1, 1] lanes.

quantize_colors

Quantize [f32; 4] colors to Unorm8x4, clamping out-of-range components.

vertex_count_of 🔒

The vertex count a stream’s enabled channels agree on, or 0 for a stream with no channels.

Type Aliases

CompressedColor

One vertex color: Unorm8x4, straight (non-premultiplied) linear RGBA.

CompressedJoints

One vertex’s joint indices: Uint16x4.

CompressedNormal

One compressed vertex normal: Snorm16x2, octahedral-encoded.

CompressedPosition

One compressed vertex position: Snorm16x4 relative to the mesh AABB.

CompressedUv

One compressed vertex UV: Snorm16x2 remapped by MeshMetadata::uv_min_and_extents.

CompressedWeights

One vertex’s joint weights: Unorm16x4, summing to 1.

JointMatrix

One joint’s skinning matrix: the joint’s transform times the inverse of the bind-pose transform, applied to a vertex in the mesh’s local space.