Skip to main content

pebble/wgpu/
buffers.rs

1pub enum BufferSource<'a> {
2    Data(&'a [u8]),
3    Buffer(wgpu::Buffer),
4}
5
6impl<'a> From<&'a [u8]> for BufferSource<'a> {
7    fn from(data: &'a [u8]) -> Self {
8        BufferSource::Data(data)
9    }
10}
11
12impl<'a> From<wgpu::Buffer> for BufferSource<'a> {
13    fn from(buffer: wgpu::Buffer) -> Self {
14        BufferSource::Buffer(buffer)
15    }
16}
17
18pub enum BindingResource<'a> {
19    UniformBuffer(BufferSource<'a>),
20    StorageBuffer(BufferSource<'a>),
21    TextureView(&'a wgpu::TextureView),
22    Sampler(&'a wgpu::Sampler),
23}
24
25pub fn build_buffer(device: &wgpu::Device, contents: &[u8], usage: wgpu::BufferUsages) -> wgpu::Buffer {
26    use wgpu::util::DeviceExt;
27    device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
28        label: None,
29        contents,
30        usage,
31    })
32}
33
34pub fn build_buffer_sized(device: &wgpu::Device, size: u64, usage: wgpu::BufferUsages) -> wgpu::Buffer {
35    device.create_buffer(&wgpu::BufferDescriptor {
36        label: None,
37        size,
38        usage,
39        mapped_at_creation: false,
40    })
41}
42
43pub fn resolve_buffer(device: &wgpu::Device, source: BufferSource<'_>, usage: wgpu::BufferUsages) -> wgpu::Buffer {
44    match source {
45        BufferSource::Data(data) => build_buffer(device, data, usage),
46        BufferSource::Buffer(buffer) => buffer,
47    }
48}
49
50pub fn resolve_uniform_buffer(device: &wgpu::Device, source: BufferSource<'_>) -> wgpu::Buffer {
51    resolve_buffer(device, source, wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST)
52}
53
54pub fn resolve_storage_buffer(device: &wgpu::Device, source: BufferSource<'_>) -> wgpu::Buffer {
55    resolve_buffer(device, source, wgpu::BufferUsages::STORAGE | wgpu::BufferUsages::COPY_DST)
56}
57
58pub fn build_uniform_bind_group<'a>(
59    device: &wgpu::Device,
60    layout: &wgpu::BindGroupLayout,
61    source: impl Into<BufferSource<'a>>,
62) -> (wgpu::Buffer, wgpu::BindGroup) {
63    let (mut buffers, bind_group) = build_bind_group(device, layout, vec![BindingResource::UniformBuffer(source.into())]);
64    (buffers.remove(0), bind_group)
65}
66
67pub fn build_storage_bind_group<'a>(
68    device: &wgpu::Device,
69    layout: &wgpu::BindGroupLayout,
70    source: impl Into<BufferSource<'a>>,
71) -> (wgpu::Buffer, wgpu::BindGroup) {
72    let (mut buffers, bind_group) = build_bind_group(device, layout, vec![BindingResource::StorageBuffer(source.into())]);
73    (buffers.remove(0), bind_group)
74}
75
76pub fn update_uniform_buffer(queue: &wgpu::Queue, buffer: &wgpu::Buffer, data: &[u8]) {
77    queue.write_buffer(buffer, 0, data);
78}
79
80/// Builds a bind group from multiple resources. Buffers created from `Data` are returned
81/// in order (texture views and samplers are not returned). Pre-built buffers passed via
82/// `Buffer` are consumed and also returned.
83pub fn build_bind_group<'a>(
84    device: &wgpu::Device,
85    layout: &wgpu::BindGroupLayout,
86    resources: Vec<BindingResource<'a>>,
87) -> (Vec<wgpu::Buffer>, wgpu::BindGroup) {
88    enum Resolved<'a> {
89        Buffer(wgpu::Buffer),
90        TextureView(&'a wgpu::TextureView),
91        Sampler(&'a wgpu::Sampler),
92    }
93
94    let resolved: Vec<Resolved> = resources
95        .into_iter()
96        .map(|r| match r {
97            BindingResource::UniformBuffer(src) => Resolved::Buffer(resolve_uniform_buffer(device, src)),
98            BindingResource::StorageBuffer(src) => Resolved::Buffer(resolve_storage_buffer(device, src)),
99            BindingResource::TextureView(view) => Resolved::TextureView(view),
100            BindingResource::Sampler(sampler) => Resolved::Sampler(sampler),
101        })
102        .collect();
103
104    let bind_group = {
105        let entries: Vec<wgpu::BindGroupEntry> = resolved
106            .iter()
107            .enumerate()
108            .map(|(i, r)| wgpu::BindGroupEntry {
109                binding: i as u32,
110                resource: match r {
111                    Resolved::Buffer(buf) => buf.as_entire_binding(),
112                    Resolved::TextureView(view) => wgpu::BindingResource::TextureView(view),
113                    Resolved::Sampler(sampler) => wgpu::BindingResource::Sampler(sampler),
114                },
115            })
116            .collect();
117
118        device.create_bind_group(&wgpu::BindGroupDescriptor {
119            label: None,
120            layout,
121            entries: &entries,
122        })
123    };
124
125    let buffers = resolved
126        .into_iter()
127        .filter_map(|r| match r {
128            Resolved::Buffer(buf) => Some(buf),
129            _ => None,
130        })
131        .collect();
132
133    (buffers, bind_group)
134}