wgpu_core/command/
allocator.rs

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1use alloc::{boxed::Box, vec::Vec};
2
3use crate::lock::{rank, Mutex};
4
5/// A pool of free [`wgpu_hal::CommandEncoder`]s, owned by a `Device`.
6///
7/// Each encoder in this list is in the "closed" state.
8///
9/// Since a raw [`CommandEncoder`][ce] is itself a pool for allocating
10/// raw [`CommandBuffer`][cb]s, this is a pool of pools.
11///
12/// [`wgpu_hal::CommandEncoder`]: hal::CommandEncoder
13/// [ce]: hal::CommandEncoder
14/// [cb]: hal::Api::CommandBuffer
15pub(crate) struct CommandAllocator {
16    free_encoders: Mutex<Vec<Box<dyn hal::DynCommandEncoder>>>,
17}
18
19impl CommandAllocator {
20    pub(crate) fn new() -> Self {
21        Self {
22            free_encoders: Mutex::new(rank::COMMAND_ALLOCATOR_FREE_ENCODERS, Vec::new()),
23        }
24    }
25
26    /// Return a fresh [`wgpu_hal::CommandEncoder`] in the "closed" state.
27    ///
28    /// If we have free encoders in the pool, take one of those. Otherwise,
29    /// create a new one on `device`.
30    ///
31    /// [`wgpu_hal::CommandEncoder`]: hal::CommandEncoder
32    pub(crate) fn acquire_encoder(
33        &self,
34        device: &dyn hal::DynDevice,
35        queue: &dyn hal::DynQueue,
36    ) -> Result<Box<dyn hal::DynCommandEncoder>, hal::DeviceError> {
37        let mut free_encoders = self.free_encoders.lock();
38        match free_encoders.pop() {
39            Some(encoder) => Ok(encoder),
40            None => unsafe {
41                let hal_desc = hal::CommandEncoderDescriptor { label: None, queue };
42                device.create_command_encoder(&hal_desc)
43            },
44        }
45    }
46
47    /// Add `encoder` back to the free pool.
48    pub(crate) fn release_encoder(&self, encoder: Box<dyn hal::DynCommandEncoder>) {
49        let mut free_encoders = self.free_encoders.lock();
50        free_encoders.push(encoder);
51    }
52}
wgpu_core/command/allocator.rs

wgpu_core/command/
allocator.rs
