JARVIGManual

ADR-0006 — WebGPU-first renderer

Status: Partially superseded Date: 2026-09-22

Context

The founding renderer is GPU-driven: scene databases, compute visibility, indirect draws, and later virtualized geometry. WebGL2 can address older hosts. It cannot be the design center.

Decision

WebGPU is the rendering target. WebGL2 is a possible compatibility backend. The CPU describes scene state and work graphs. The Phase 0 RenderDevice interface allows webgpu, webgl2, and null. Shipping hosts currently use null so they boot without a GPU. That does not add a third permanent backend. null is a test and headless stand-in.

Alternatives Considered

  • WebGL2-first, WebGPU later. Rejected. The GPU-driven design would be bent around WebGL2 limits and then rewritten.
  • A native graphics API as the first backend. Rejected until a measured port. The founding target is WebGPU.

Consequences

Material codegen targets WGSL. A WebGL2 backend, if built, consumes the same Material IR. Simulation code does not call the GPU API.

Supersedes

Nothing.

Superseded By

ADR-0017 supersedes the reading that WebGPU means a browser renderer, and the rejection of a native graphics API as a first backend. WebGPU remains the first RHI backend (native wgpu and browser WebGPU). D3D12, Vulkan, and a later Metal backend are RHI implementations, not a different engine.