egui-ash

egui integration for ash (Vulkan).

Manages the winit event loop, Vulkan swapchains, and egui rendering so that consumers only need to implement two traits. Supports egui multi-viewports, render-to-texture scene views, and custom Vulkan rendering alongside egui.

Features

• Full egui multi-viewport support (immediate and deferred viewports each get their own swapchain)
• Bring your own allocator via the Allocator trait, or use the ready-made gpu-allocator integration
• Render custom Vulkan content alongside egui via HandleRedraw::Handle
• Embed Vulkan-rendered textures inside egui panels via ImageRegistry
• Optional window layout and egui memory persistence via RON files

Usage

Add the dependency:

[dependencies]
egui-ash = { version = "0.4", features = ["gpu-allocator"] }

Implement App and AppCreator, then call run:

use egui_ash::{App, AppCreator, AshRenderState, CreationContext, HandleRedraw, RunOption};

struct MyApp;
impl App for MyApp {
    fn ui(&mut self, ctx: &egui::Context) {
        egui::CentralPanel::default().show(ctx, |ui| {
            ui.heading("Hello egui-ash!");
        });
    }

    fn request_redraw(&mut self, _viewport_id: egui::ViewportId) -> HandleRedraw {
        // Return Auto to let egui-ash handle presentation,
        // or Handle(Box::new(|size, egui_cmd| { ... })) to drive your own Vulkan render loop.
        HandleRedraw::Auto
    }
}

struct MyAppCreator;
impl AppCreator<Arc<Mutex<gpu_allocator::vulkan::Allocator>>> for MyAppCreator {
    type App = MyApp;

    fn create(&self, cc: CreationContext) -> (Self::App, AshRenderState<Arc<Mutex<gpu_allocator::vulkan::Allocator>>>) {
        // Create your Vulkan instance, device, allocator, etc. using the extension
        // lists provided in `cc.required_instance_extensions` and
        // `cc.required_device_extensions`, then return them via AshRenderState.
        let ash_render_state = AshRenderState { /* ... */ };
        (MyApp, ash_render_state)
    }
}

fn main() -> std::process::ExitCode {
    egui_ash::run(
        "my-app",
        MyAppCreator,
        RunOption {
            viewport_builder: Some(
                egui::ViewportBuilder::default().with_title("My App"),
            ),
            ..Default::default()
        },
    )
}

See the examples for complete working code covering egui-only rendering, custom Vulkan rendering, multi-viewports, render-to-texture scene views, and image loading.

Custom Vulkan rendering

When you need to draw Vulkan content on the same window as egui, return HandleRedraw::Handle from request_redraw. The closure receives the window size and an EguiCommand handle; call egui_cmd.update_swapchain on first render and after resize, then egui_cmd.record to append the egui draw calls to your command buffer:

fn request_redraw(&mut self, _viewport_id: egui::ViewportId) -> HandleRedraw {
    HandleRedraw::Handle(Box::new({
        let renderer = self.renderer.clone();
        move |size, egui_cmd| renderer.render(size.width, size.height, egui_cmd)
    }))
}

Render-to-texture

Register an off-screen color image view with ImageRegistry::register_user_texture to obtain an egui::TextureId. Pass that id to egui::Image to embed Vulkan-rendered content inside any egui panel. Unregister with unregister_user_texture when the image is destroyed.

Feature flags

Feature	Description
gpu-allocator	Implements Allocator for Arc<Mutex<gpu_allocator::vulkan::Allocator>>
persistence	Saves/restores window layout and egui memory to disk via RON, keyed by app_id
wayland	Wayland support (passed through to egui-winit)
x11	X11 support (passed through to egui-winit)
accesskit	Accessibility support (passed through to egui-winit)

License

MIT OR Apache-2.0