ff-render 0.14.2

use crate::error::RenderError;

/// Owns the wgpu device and queue used by the render pipeline.
///
/// Share via `Arc<RenderContext>` when multiple components (graph, sink, etc.)
/// need access to the same GPU device.
pub struct RenderContext {
    pub device: wgpu::Device,
    pub queue: wgpu::Queue,
}

impl RenderContext {
    /// Wrap an existing wgpu device (e.g. shared with the window renderer).
    #[must_use]
    pub fn new(device: wgpu::Device, queue: wgpu::Queue) -> Self {
        Self { device, queue }
    }

    /// Initialise wgpu using the default (best available) backend.
    ///
    /// Backend priority: Metal → Vulkan → DX12 → WebGPU → OpenGL.
    ///
    /// # Errors
    ///
    /// Returns [`RenderError::DeviceCreation`] if no suitable adapter is found or
    /// the device request fails.
    pub async fn init() -> Result<Self, RenderError> {
        Self::init_with_backend(wgpu::Backends::all()).await
    }

    /// Initialise wgpu with an explicit backend set.
    ///
    /// Useful in CI where only `wgpu::Backends::GL` may be available.
    ///
    /// # Errors
    ///
    /// Returns [`RenderError::DeviceCreation`] if no suitable adapter is found or
    /// the device request fails.
    pub async fn init_with_backend(backends: wgpu::Backends) -> Result<Self, RenderError> {
        let instance = wgpu::Instance::new(wgpu::InstanceDescriptor {
            backends,
            flags: wgpu::InstanceFlags::default(),
            memory_budget_thresholds: wgpu::MemoryBudgetThresholds::default(),
            backend_options: wgpu::BackendOptions::default(),
            display: None,
        });

        let adapter = instance
            .request_adapter(&wgpu::RequestAdapterOptions {
                power_preference: wgpu::PowerPreference::HighPerformance,
                force_fallback_adapter: false,
                compatible_surface: None,
            })
            .await
            .map_err(|e| RenderError::DeviceCreation {
                message: e.to_string(),
            })?;

        log::info!(
            "render adapter selected backend={:?} name={}",
            adapter.get_info().backend,
            adapter.get_info().name
        );

        let (device, queue) = adapter
            .request_device(&wgpu::DeviceDescriptor {
                label: Some("ff-render"),
                ..Default::default()
            })
            .await
            .map_err(|e| RenderError::DeviceCreation {
                message: e.to_string(),
            })?;

        Ok(Self { device, queue })
    }
}