wgpu-weld

Weld Chromium Embedded Framework rendered output into wgpu-importable GPU textures via CEF's accelerated off-screen rendering (OSR).

This repo was created as a sibling to wgpu-graft (Servo testbed, GL-FBO / Vulkan / Metal / D3D interop) and wgpu-scry (system-webview frame adapter — WebView2 / WKWebView / WebKitGTK).

wgpu-weld covers the CEF side: rather than using the OS's built-in webview, the embedder bundles Chromium and routes CEF's OnAcceleratedPaint output into host-owned wgpu textures. CEF hands out callback-scoped native handles, so the core rule is "duplicate or retain inside the paint callback, then import into wgpu from the host side." The trade-off is binary size and a more complex process model (see CEF Foibles in the welding crate docs) in exchange for a single cross-platform producer, uniform browser behaviour, and direct access to the CEF DevTools protocol.

Workspace

Crate	Purpose
welding	The library. CefRuntime initialization/subprocess detection, native-frame mailbox, Windows D3D shared-handle → wgpu D3D12 import, and the CefSurfaceProducer trait. CEF vtable/browser creation is still pending.
demo-weld-win	Windows runtime probe. Currently validates the subprocess/runtime entry shape; live CEF frame rendering waits on the client/render-handler wiring.

See welding/README.md for the producer/consumer contract and the platform texture paths.

Quick start

# cargo check does not require CEF_PATH; runtime initialization does.
set CEF_PATH=C:\path\to\cef_binary_147.x_windows64

cargo check -p welding
cargo run -p demo-weld-win

Relationship to wgpu-scry and wgpu-graft

All three repos are structurally derived from the same pattern — native GPU surface handles produced by an embedded browser, imported into a host wgpu pipeline — but serve different niches:

Repo	Engine	Distribution	Producers
wgpu-graft	Servo	bundled	1 (Servo via surfman / GL-FBO)
wgpu-scry	OS webview	OS-provided	3 (WebView2, WKWebView, WPE)
wgpu-weld	Chromium (CEF)	bundled	1 cross-platform

wgpu-weld ships the engine; wgpu-scry uses the OS's. CEF's single cross-platform producer means one implementation family to maintain, and OnAcceleratedPaint gives a more direct texture source than WGC capture. The hard part moves to CEF's C ABI/vtable ownership and callback-scoped handle lifetime.

License

MPL-2.0