Struct SecondaryStreamWriter 

pub struct SecondaryStreamWriter {
    pub flags: SecondaryFlags,
}

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

Each channel adds one attribute to crate::pipeline::SECONDARY_SLOT, in the order UV, color then normal, so the packed stream matches the shader’s declared locations for any combination. Self::write compresses the raw attributes and interleaves them straight into the target buffer.

Fields

flags: SecondaryFlags

The channels this stream writes.

Implementations

impl SecondaryStreamWriter

pub fn uv(&self) -> bool

Whether the UV attribute is written.

pub fn color(&self) -> bool

Whether the color attribute is written.

pub fn normal(&self) -> bool

Whether the normal attribute is written.

pub fn uncompressed_uv(&self) -> bool

Whether the UV is written full precision rather than compressed to Snorm16x2.

An uncompressed UV needs no decode parameters, so Self::write leaves the metadata alone.

pub fn is_empty(&self) -> bool

Whether the variant declares no attributes at all, in which case the slot must be omitted from the vertex-buffer list.

pub fn channels(&self) -> StreamChannels

The channels this stream carries, in attribute order.

The single description the stride, the attribute offsets and the packed bytes are all derived from.

pub fn stride(&self) -> u32

Bytes per vertex of the packed stream.

pub fn byte_len(&self, vertex_count: usize) -> usize

Bytes one vertex_count-long stream occupies.

pub fn write( &self, uvs: &[[f32; 2]], colors: &[CompressedColor], normals: &[[f32; 3]], metadata: &mut MeshMetadata, out: WriteOnly<'_, [u8]>, )

Compress the raw uvs and normals and write the interleaved result, together with the already compressed colors, into out — which must be exactly Self::byte_len(vertex_count) bytes, normally a mapped-at-creation vertex buffer, so the vertices land in GPU memory without an intermediate byte buffer.

Colors are taken as CompressedColor because that is what the stream stores; float colors from a [glam::Vec4] can be quantized with quantize_colors first. Normals need no such preparation: the octahedral encoding is absolute, so they are compressed here.

metadata receives the UV decode parameters the compression derives, exactly as compress_uvs would.

Nothing is allocated: the compressed UVs are produced lazily and written as they are computed. Use Self::write_compressed to write channels that are already compressed, for example to share one stream across several meshes.

Panics

If an enabled channel has no matching slice, if the channel lengths disagree, or if out is not exactly one stream long.

pub fn write_compressed( &self, uvs: &[CompressedUv], colors: &[CompressedColor], normals: &[CompressedNormal], out: WriteOnly<'_, [u8]>, )

Write the already compressed uvs, colors and normals into out as the interleaved vertex stream, which must be exactly Self::byte_len(vertex_count) bytes.

Takes the packed form produced by compress_uvs, quantize_colors and compress_normals, so one compressed stream can be uploaded for several meshes without recompressing it.

Panics

If an enabled channel has no matching slice, if the channel lengths disagree, or if out is not exactly one stream long.

fn raw_vertex_count( &self, uvs: &[[f32; 2]], colors: &[CompressedColor], normals: &[[f32; 3]], ) -> usize

Number of vertices the raw channel slices describe.

Every enabled channel describes the same vertices, so the first one sets the count and the rest must agree; a stream whose channels disagree has no length that would pack them together.

fn compressed_vertex_count( &self, uvs: &[CompressedUv], colors: &[CompressedColor], normals: &[CompressedNormal], ) -> usize

Number of vertices the compressed channel slices describe.

Trait Implementations

impl Clone for SecondaryStreamWriter

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for SecondaryStreamWriter

impl Debug for SecondaryStreamWriter

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

Formats the value using the given formatter.

impl Default for SecondaryStreamWriter

fn default() -> Self

Returns the “default value” for a type.

impl Eq for SecondaryStreamWriter

impl PartialEq for SecondaryStreamWriter

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for SecondaryStreamWriter