40 lines
1.3 KiB
Rust
40 lines
1.3 KiB
Rust
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use crate::descriptors::Descriptors;
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use bytemuck::{AnyBitPattern, NoUninit};
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use wgpu::util::DeviceExt;
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pub struct BufferBuilder {
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inner: Vec<u8>,
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align_mask: usize,
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}
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impl BufferBuilder {
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pub fn new(descriptors: &Descriptors) -> Self {
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let align_mask = (descriptors.limits.min_uniform_buffer_offset_alignment - 1) as usize;
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Self {
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inner: Vec::new(),
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align_mask,
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}
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}
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pub fn add<T: NoUninit + AnyBitPattern>(&mut self, value: T) -> wgpu::BufferAddress {
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if !self.inner.is_empty() {
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// Pad the internal buffer to match alignment requirements
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// Pad on creation so that we don't wastefully pad the end of the buffer
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let length = (self.inner.len() + self.align_mask) & !self.align_mask;
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self.inner.resize(length, 0);
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}
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let address = self.inner.len() as wgpu::BufferAddress;
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self.inner.extend_from_slice(bytemuck::cast_slice(&[value]));
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address
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}
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pub fn finish(self, device: &wgpu::Device, label: Option<String>) -> wgpu::Buffer {
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device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
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label: label.as_deref(),
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contents: &self.inner,
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usage: wgpu::BufferUsages::UNIFORM,
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})
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}
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}
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