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use std::ops::{Deref, DerefMut};
use crate::*;
/// Handle to a command queue on a device.
///
/// A `Queue` executes recorded [`CommandBuffer`] objects and provides convenience methods
/// for writing to [buffers](Queue::write_buffer) and [textures](Queue::write_texture).
/// It can be created along with a [`Device`] by calling [`Adapter::request_device`].
///
/// Corresponds to [WebGPU `GPUQueue`](https://gpuweb.github.io/gpuweb/#gpu-queue).
#[derive(Debug, Clone)]
pub struct Queue {
pub(crate) inner: dispatch::DispatchQueue,
}
#[cfg(send_sync)]
static_assertions::assert_impl_all!(Queue: Send, Sync);
crate::cmp::impl_eq_ord_hash_proxy!(Queue => .inner);
/// Identifier for a particular call to [`Queue::submit`]. Can be used
/// as part of an argument to [`Device::poll`] to block for a particular
/// submission to finish.
///
/// This type is unique to the Rust API of `wgpu`.
/// There is no analogue in the WebGPU specification.
#[derive(Debug, Clone)]
pub struct SubmissionIndex {
#[cfg_attr(
all(
target_arch = "wasm32",
not(target_os = "emscripten"),
not(feature = "webgl"),
),
expect(dead_code)
)]
pub(crate) index: u64,
}
#[cfg(send_sync)]
static_assertions::assert_impl_all!(SubmissionIndex: Send, Sync);
pub use wgt::Maintain as MaintainBase;
/// Passed to [`Device::poll`] to control how and if it should block.
pub type Maintain = wgt::Maintain<SubmissionIndex>;
#[cfg(send_sync)]
static_assertions::assert_impl_all!(Maintain: Send, Sync);
/// A write-only view into a staging buffer.
///
/// Reading into this buffer won't yield the contents of the buffer from the
/// GPU and is likely to be slow. Because of this, although [`AsMut`] is
/// implemented for this type, [`AsRef`] is not.
pub struct QueueWriteBufferView<'a> {
queue: &'a Queue,
buffer: &'a Buffer,
offset: BufferAddress,
inner: dispatch::DispatchQueueWriteBuffer,
}
#[cfg(send_sync)]
static_assertions::assert_impl_all!(QueueWriteBufferView<'_>: Send, Sync);
impl Deref for QueueWriteBufferView<'_> {
type Target = [u8];
fn deref(&self) -> &Self::Target {
log::warn!("Reading from a QueueWriteBufferView won't yield the contents of the buffer and may be slow.");
self.inner.slice()
}
}
impl DerefMut for QueueWriteBufferView<'_> {
fn deref_mut(&mut self) -> &mut Self::Target {
self.inner.slice_mut()
}
}
impl AsMut<[u8]> for QueueWriteBufferView<'_> {
fn as_mut(&mut self) -> &mut [u8] {
self.inner.slice_mut()
}
}
impl Drop for QueueWriteBufferView<'_> {
fn drop(&mut self) {
self.queue
.inner
.write_staging_buffer(&self.buffer.inner, self.offset, &self.inner);
}
}
impl Queue {
/// Schedule a data write into `buffer` starting at `offset`.
///
/// This method fails if `data` overruns the size of `buffer` starting at `offset`.
///
/// This does *not* submit the transfer to the GPU immediately. Calls to
/// `write_buffer` begin execution only on the next call to
/// [`Queue::submit`]. To get a set of scheduled transfers started
/// immediately, it's fine to call `submit` with no command buffers at all:
///
/// ```no_run
/// # let queue: wgpu::Queue = todo!();
/// queue.submit([]);
/// ```
///
/// However, `data` will be immediately copied into staging memory, so the
/// caller may discard it any time after this call completes.
///
/// If possible, consider using [`Queue::write_buffer_with`] instead. That
/// method avoids an intermediate copy and is often able to transfer data
/// more efficiently than this one.
pub fn write_buffer(&self, buffer: &Buffer, offset: BufferAddress, data: &[u8]) {
self.inner.write_buffer(&buffer.inner, offset, data);
}
/// Write to a buffer via a directly mapped staging buffer.
///
/// Return a [`QueueWriteBufferView`] which, when dropped, schedules a copy
/// of its contents into `buffer` at `offset`. The returned view
/// dereferences to a `size`-byte long `&mut [u8]`, in which you should
/// store the data you would like written to `buffer`.
///
/// This method may perform transfers faster than [`Queue::write_buffer`],
/// because the returned [`QueueWriteBufferView`] is actually the staging
/// buffer for the write, mapped into the caller's address space. Writing
/// your data directly into this staging buffer avoids the temporary
/// CPU-side buffer needed by `write_buffer`.
///
/// Reading from the returned view is slow, and will not yield the current
/// contents of `buffer`.
///
/// Note that dropping the [`QueueWriteBufferView`] does *not* submit the
/// transfer to the GPU immediately. The transfer begins only on the next
/// call to [`Queue::submit`] after the view is dropped. To get a set of
/// scheduled transfers started immediately, it's fine to call `submit` with
/// no command buffers at all:
///
/// ```no_run
/// # let queue: wgpu::Queue = todo!();
/// queue.submit([]);
/// ```
///
/// This method fails if `size` is greater than the size of `buffer` starting at `offset`.
#[must_use]
pub fn write_buffer_with<'a>(
&'a self,
buffer: &'a Buffer,
offset: BufferAddress,
size: BufferSize,
) -> Option<QueueWriteBufferView<'a>> {
profiling::scope!("Queue::write_buffer_with");
self.inner
.validate_write_buffer(&buffer.inner, offset, size)?;
let staging_buffer = self.inner.create_staging_buffer(size)?;
Some(QueueWriteBufferView {
queue: self,
buffer,
offset,
inner: staging_buffer,
})
}
/// Schedule a write of some data into a texture.
///
/// * `data` contains the texels to be written, which must be in
/// [the same format as the texture](TextureFormat).
/// * `data_layout` describes the memory layout of `data`, which does not necessarily
/// have to have tightly packed rows.
/// * `texture` specifies the texture to write into, and the location within the
/// texture (coordinate offset, mip level) that will be overwritten.
/// * `size` is the size, in texels, of the region to be written.
///
/// This method fails if `size` overruns the size of `texture`, or if `data` is too short.
///
/// This does *not* submit the transfer to the GPU immediately. Calls to
/// `write_texture` begin execution only on the next call to
/// [`Queue::submit`]. To get a set of scheduled transfers started
/// immediately, it's fine to call `submit` with no command buffers at all:
///
/// ```no_run
/// # let queue: wgpu::Queue = todo!();
/// queue.submit([]);
/// ```
///
/// However, `data` will be immediately copied into staging memory, so the
/// caller may discard it any time after this call completes.
pub fn write_texture(
&self,
texture: TexelCopyTextureInfo<'_>,
data: &[u8],
data_layout: TexelCopyBufferLayout,
size: Extent3d,
) {
self.inner.write_texture(texture, data, data_layout, size);
}
/// Schedule a copy of data from `image` into `texture`.
#[cfg(any(webgpu, webgl))]
pub fn copy_external_image_to_texture(
&self,
source: &wgt::CopyExternalImageSourceInfo,
dest: wgt::CopyExternalImageDestInfo<&api::Texture>,
size: Extent3d,
) {
self.inner
.copy_external_image_to_texture(source, dest, size);
}
/// Submits a series of finished command buffers for execution.
pub fn submit<I: IntoIterator<Item = CommandBuffer>>(
&self,
command_buffers: I,
) -> SubmissionIndex {
let mut command_buffers = command_buffers.into_iter().map(|comb| {
comb.inner
.lock()
.take()
.expect("Command buffer already submitted")
});
let index = self.inner.submit(&mut command_buffers);
SubmissionIndex { index }
}
/// Gets the amount of nanoseconds each tick of a timestamp query represents.
///
/// Returns zero if timestamp queries are unsupported.
///
/// Timestamp values are represented in nanosecond values on WebGPU, see `<https://gpuweb.github.io/gpuweb/#timestamp>`
/// Therefore, this is always 1.0 on the web, but on wgpu-core a manual conversion is required.
pub fn get_timestamp_period(&self) -> f32 {
self.inner.get_timestamp_period()
}
/// Registers a callback when the previous call to submit finishes running on the gpu. This callback
/// being called implies that all mapped buffer callbacks which were registered before this call will
/// have been 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 on_submitted_work_done(&self, callback: impl FnOnce() + Send + 'static) {
self.inner.on_submitted_work_done(Box::new(callback));
}
}