Method acquire

native/shared/src/renderer/transient.rs:175–212

Acquire a transient matching `desc`. Returns either a freed slot from the reuse pool or allocates a new one via `device`. The returned handle is valid until `release()` or the next resize.

(&mut self, device: &wgpu::Device, desc: TransientDesc)

    /// The returned handle is valid until `release()` or the next
    /// resize.
    pub fn acquire(&mut self, device: &wgpu::Device, desc: TransientDesc) -> TransientId {
        let target_extent = desc.size.extent(self.swap_size.0, self.swap_size.1);

        // Look for an existing free slot with identical desc + extent.
        for slot in self.slots.iter_mut() {
            if !slot.in_use
                && slot.desc == desc
                && slot.extent == target_extent
            {
                slot.in_use = true;
                return TransientId(slot.id);
            }
        }

        // Nothing matched — allocate a new slot.
        let texture = device.create_texture(&wgpu::TextureDescriptor {
            label: Some("transient"),
            size: wgpu::Extent3d {
                width: target_extent.0,
                height: target_extent.1,
                depth_or_array_layers: 1,
            },
            mip_level_count: desc.mips,
            sample_count: desc.samples,
            dimension: wgpu::TextureDimension::D2,
            format: desc.format,
            usage: desc.usage,
            view_formats: &[],
        });
        let view = texture.create_view(&wgpu::TextureViewDescriptor::default());
        let id = self.next_id;
        self.next_id += 1;
        // Ids are stable — surviving slots keep theirs across resizes
        // (which can drop swapchain-relative slots and shrink the Vec),
        // so handle lookups stay valid even when the slot index shifts.
        self.slots.push(Slot { id, desc, extent: target_extent, texture, view, in_use: true });
        TransientId(id)
    }

    /// Mark a transient as no longer in use. The slot returns to the
    /// reuse pool and can be handed back to a subsequent `acquire`