Struct rerun::external::eframe::egui_wgpu::wgpu::BufferSlice

pub struct BufferSlice<'a> {
    pub(crate) buffer: &'a Buffer,
    pub(crate) offset: u64,
    pub(crate) size: Option<NonZero<u64>>,
}

A slice of a Buffer, to be mapped, used for vertex or index data, or the like.

You can create a BufferSlice by calling Buffer::slice:

let slice = buffer.slice(10..20);

This returns a slice referring to the second ten bytes of buffer. To get a slice of the entire Buffer:

let whole_buffer_slice = buffer.slice(..);

You can pass buffer slices to methods like RenderPass::set_vertex_buffer and RenderPass::set_index_buffer to indicate which portion of the buffer a draw call should consult.

To access the slice’s contents on the CPU, you must first map the buffer, and then call BufferSlice::get_mapped_range or BufferSlice::get_mapped_range_mut to obtain a view of the slice’s contents. See the documentation on mapping for more details, including example code.

Unlike a Rust shared slice &[T], whose existence guarantees that nobody else is modifying the T values to which it refers, a BufferSlice doesn’t guarantee that the buffer’s contents aren’t changing. You can still record and submit commands operating on the buffer while holding a BufferSlice. A BufferSlice simply represents a certain range of the buffer’s bytes.

The BufferSlice type is unique to the Rust API of wgpu. In the WebGPU specification, an offset and size are specified as arguments to each call working with the Buffer, instead.

Fields

buffer: &'a Buffer

offset: u64

size: Option<NonZero<u64>>

Implementations

impl<'a> BufferSlice<'a>

pub fn map_async( &self, mode: MapMode, callback: impl FnOnce(Result<(), BufferAsyncError>) + WasmNotSend + 'static )

Map the buffer. Buffer is ready to map once the callback is called.

For the callback to complete, either queue.submit(..), instance.poll_all(..), or device.poll(..) must be called elsewhere in the runtime, possibly integrated into an event loop or run on a separate thread.

The callback will be called on the thread that first calls the above functions after the gpu work has completed. There are no restrictions on the code you can run in the callback, however on native the call to the function will not complete until the callback returns, so prefer keeping callbacks short and used to set flags, send messages, etc.

pub fn get_mapped_range(&self) -> BufferView<'a>

Gain read-only access to the bytes of a mapped Buffer.

Return a BufferView referring to the buffer range represented by self. See the documentation for BufferView for details.

Panics

• This panics if the buffer to which self refers is not currently mapped.

• If you try to create overlapping views of a buffer, mutable or otherwise, get_mapped_range will panic.

pub fn get_mapped_range_mut(&self) -> BufferViewMut<'a>

Gain write access to the bytes of a mapped Buffer.

Return a BufferViewMut referring to the buffer range represented by self. See the documentation for BufferViewMut for more details.

Panics

• This panics if the buffer to which self refers is not currently mapped.

• If you try to create overlapping views of a buffer, mutable or otherwise, get_mapped_range_mut will panic.

Trait Implementations

impl<'a> Clone for BufferSlice<'a>

fn clone(&self) -> BufferSlice<'a>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for BufferSlice<'a>

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

Formats the value using the given formatter.

impl<'a> Copy for BufferSlice<'a>