Browser Platform

SiliconGhetto is a WebGPU-based browser game engine. WebGPU is the default renderer. WebGL2 exists only as an automatic fallback when hardware WebGPU is unavailable or unsuitable.

No URL flag, query parameter, or user setting is required. The engine chooses the correct renderer during initialization.

Minimum Requirements

Feature	Required	Fallback
WebAssembly	Yes	None
WebGPU	Primary/default renderer	WebGL2 fallback
WebGL2	Required only for fallback	None
Web Workers	Yes	Main thread mode
OffscreenCanvas	Preferred	Main thread rendering
SharedArrayBuffer	Optional	Single-threaded

Rendering Tiers

Tier 1: WebGPU

Capability	Requirement	Result
GPU API	Hardware WebGPU adapter exposed by the browser	Primary renderer
Shader path	WGSL through wgpu	Full engine feature path
Advanced GPU features	Available according to adapter limits	Highest quality tiers where supported

Tier 2: WebGL2 Fallback

Capability	Requirement	Result
GPU API	WebGL2 context available	Fallback renderer
WebGPU state	Unavailable, rejected, or software/fallback adapter	Automatic fallback
Feature set	WebGL2-compatible shader and buffer limits	Reduced renderer features

Not Supported

Browsers without WebAssembly support
Browsers without hardware WebGPU or WebGL2 support

Feature Detection

The engine detects GPU capabilities at initialization:

1. Request a WebGPU adapter
   - Hardware adapter found: use WebGPU
   - No adapter, rejected adapter, or software adapter: use WebGL2 fallback
2. Query device limits and features
3. Configure rendering pipelines from the selected backend

WebGPU Feature Path

These features require WebGPU and are unavailable on WebGL2:

Compute shaders
Storage textures
Timestamp queries for GPU profiling
Indirect draw calls

WebGL2 Fallback Limits

When running on WebGL2:

No compute shader support
Limited texture format support
No storage buffers
Some shader features are restricted

Cross-Origin Isolation

SiliconGhetto requires cross-origin isolation headers for full functionality:

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp

Without these headers:

SharedArrayBuffer is unavailable
High-resolution timers may be restricted
Memory measurement APIs are unavailable

All deployment configurations include these headers. See ADR-003.

Mobile Support

Mobile browsers follow the same automatic renderer policy: hardware WebGPU first, WebGL2 fallback only when needed.

Mobile-specific considerations:

Touch input: Handled via the sg_input crate’s touch abstraction
Screen orientation: Games should handle both portrait and landscape
GPU thermal throttling: Runtime quality tiers adapt to sustained pressure
Memory constraints: Mobile devices may use lower asset quality or shorter draw distances

Testing Platform

# Build a demo
wasm-pack build demos/stress-lab --target web --out-dir www/pkg

# Serve with isolation headers
# Open in a target browser and check console diagnostics for backend info

The runtime diagnostics report:

GPU backend selected by the automatic policy
Device capabilities
Frame rate and performance metrics
Quality tier selection

Known Constraints

WebGL2 fallback has reduced rendering features compared with WebGPU.
Software WebGPU adapters are treated as unsuitable for gameplay and fall back to WebGL2 when available.
Browser GPU support changes over time, so the engine relies on runtime capability detection instead of hard-coded browser lists.