dynamis_gpu/
buffer.rs

1use std::sync::mpsc::{self, TryRecvError};
2use wgpu::{
3    Buffer, BufferAddress, BufferDescriptor, BufferUsages, Device, MapMode, PollType, Queue,
4};
5
6pub struct GpuBuffer {
7    buffer: Buffer,
8    size: BufferAddress,
9}
10
11impl GpuBuffer {
12    pub fn new(device: &Device, label: &str, size: BufferAddress, usage: BufferUsages) -> Self {
13        let buffer = device.create_buffer(&BufferDescriptor {
14            label: Some(label),
15            size,
16            usage,
17            mapped_at_creation: false,
18        });
19        Self { buffer, size }
20    }
21
22    pub fn write(&self, queue: &Queue, bytes: &[u8]) {
23        assert!(bytes.len() as u64 <= self.size, "write exceeds buffer size");
24        queue.write_buffer(&self.buffer, 0, bytes);
25    }
26
27    pub fn as_entire_binding(&self) -> wgpu::BindingResource<'_> {
28        wgpu::BindingResource::Buffer(wgpu::BufferBinding {
29            buffer: &self.buffer,
30            offset: 0,
31            size: None,
32        })
33    }
34
35    pub fn as_indirect_target(&self) -> &Buffer {
36        &self.buffer
37    }
38
39    pub fn size(&self) -> BufferAddress {
40        self.size
41    }
42
43    pub fn buffer(&self) -> &Buffer {
44        &self.buffer
45    }
46
47    pub fn read_sync(&self, device: &Device, queue: &Queue) -> Vec<u8> {
48        let staging = device.create_buffer(&BufferDescriptor {
49            label: Some("readback staging"),
50            size: self.size,
51            usage: BufferUsages::COPY_DST | BufferUsages::MAP_READ,
52            mapped_at_creation: false,
53        });
54        let mut encoder = device.create_command_encoder(&wgpu::CommandEncoderDescriptor {
55            label: Some("readback encoder"),
56        });
57        encoder.copy_buffer_to_buffer(&self.buffer, 0, &staging, 0, self.size);
58        queue.submit([encoder.finish()]);
59
60        let slice = staging.slice(..);
61        let (sender, receiver) = mpsc::channel();
62        slice.map_async(MapMode::Read, move |result| {
63            let _ = sender.send(result);
64        });
65        loop {
66            device
67                .poll(PollType::wait_indefinitely())
68                .expect("device lost while awaiting readback");
69            match receiver.try_recv() {
70                Ok(Ok(())) => break,
71                Ok(Err(error)) => panic!("buffer mapping failed: {error}"),
72                Err(TryRecvError::Empty) => std::thread::yield_now(),
73                Err(TryRecvError::Disconnected) => panic!("mapping callback was dropped"),
74            }
75        }
76        let bytes = slice
77            .get_mapped_range()
78            .expect("mapped range unavailable")
79            .to_vec();
80        staging.unmap();
81        bytes
82    }
83}
dynamis_gpu/buffer.rs

dynamis_gpu/
buffer.rs
