pebble-engine 0.17.0

A modular, ECS-style graphics/app framework for Rust.
Documentation 
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use crate::wgpu::{buffer::Buffer, buffers::BindGroup, compute::ComputePipeline};

/// A compute pass, opaque — the value [`CommandEncoder::compute_pass`]/
/// [`WGPUFrame::compute_pass`](super::backend::WGPUFrame::compute_pass)
/// hand back. There's no way to reach the underlying `wgpu::ComputePass`
/// from outside this crate.
pub struct ComputePass<'a> {
    raw: wgpu::ComputePass<'a>,
}

impl<'a> ComputePass<'a> {
    pub(crate) fn new(raw: wgpu::ComputePass<'a>) -> Self {
        Self { raw }
    }

    pub fn set_pipeline(&mut self, pipeline: &ComputePipeline) {
        self.raw.set_pipeline(pipeline.raw());
    }

    /// `offsets` is the dynamic-offset slice for any dynamic-offset entries
    /// in this bind group's layout, in the order they appear — empty if
    /// none. See [`RenderPass::set_bind_group`](super::render_pass::RenderPass::set_bind_group).
    pub fn set_bind_group(&mut self, index: u32, bind_group: &BindGroup, offsets: &[u32]) {
        self.raw.set_bind_group(index, Some(bind_group.raw()), offsets);
    }

    pub fn dispatch_workgroups(&mut self, x: u32, y: u32, z: u32) {
        self.raw.dispatch_workgroups(x, y, z);
    }

    /// Same as [`dispatch_workgroups`](Self::dispatch_workgroups), but the
    /// workgroup counts come from a [`DispatchIndirectArgs`] value already
    /// written into `indirect_buffer` at `indirect_offset` bytes — for a
    /// dispatch size the GPU itself computed (culling compaction, particle
    /// counts, ...) the CPU never reads back.
    pub fn dispatch_workgroups_indirect(&mut self, indirect_buffer: &'a Buffer, indirect_offset: u64) {
        self.raw.dispatch_workgroups_indirect(indirect_buffer.raw(), indirect_offset);
    }
}

/// The argument layout [`ComputePass::dispatch_workgroups_indirect`]
/// expects — mirrors `wgpu::DispatchIndirectArgs` field-for-field. See
/// [`DrawIndirectArgs`](super::render_pass::DrawIndirectArgs).
#[repr(C)]
#[derive(Copy, Clone, Debug, Default, bytemuck::Pod, bytemuck::Zeroable)]
pub struct DispatchIndirectArgs {
    pub x: u32,
    pub y: u32,
    pub z: u32,
}

impl DispatchIndirectArgs {
    pub fn as_bytes(&self) -> &[u8] {
        bytemuck::bytes_of(self)
    }
}

/// A command encoder, opaque — built only via
/// [`WGPUBackend::create_command_encoder`](super::backend::WGPUBackend::create_command_encoder).
/// Its only job is starting a [`ComputePass`]; submit it when done via
/// [`WGPUBackend::submit`](super::backend::WGPUBackend::submit). Render
/// passes don't need this — [`ActiveFrame::begin_pass`](crate::rendering::active_frame::ActiveFrame::begin_pass)
/// manages its own frame-tied encoder internally.
pub struct CommandEncoder {
    raw: wgpu::CommandEncoder,
}

impl CommandEncoder {
    pub(crate) fn new(raw: wgpu::CommandEncoder) -> Self {
        Self { raw }
    }

    pub fn compute_pass(&mut self, label: Option<&str>) -> ComputePass<'_> {
        let raw = self.raw.begin_compute_pass(&wgpu::ComputePassDescriptor {
            label,
            timestamp_writes: None,
        });
        ComputePass::new(raw)
    }

    pub(crate) fn into_raw(self) -> wgpu::CommandEncoder {
        self.raw
    }
}