ADR 001: WebGPU Renderer Strategy

Status: Accepted (Phase 2 complete — v1.17)
Date: 2026-07-05
Stage: 01-render-engine-performance (tasks 1.1–1.3, 1.2)

Context

ChartOptions.renderer accepts "webgl" | "webgpu". Experimental code existed in src/gpu/ but was not wired as the chart renderer.

Decision

1. renderer: "webgl" (default) — NativeWebGLRenderer.
2. renderer: "webgpu" — GpuChartRenderer with WebGPU backend; WebGL2 fallback if unavailable.
3. PluginGpu — GPU compute experiments outside the chart loop.

Implementation (v1.17)

Component	Path
Chart adapter	src/renderer/GpuChartRenderer.ts
GPU facade	src/gpu/adapter/gpuRenderer.ts — renderNativeSeries()
WebGPU triangles	WebGPUBackend.renderSolidTriangles() — uniform-color bars/boxes
Benchmarks	line-200k-webgl / line-200k-webgpu + evaluateRendererCompare()

Chart WebGPU parity

Series	WebGPU
line, scatter, step, band, bar, heatmap	✅
candlestick	✅ (bullish/bearish triangles)
boxplot	✅ (faces + whiskers)
waterfall	✅ (pos/neg/subtotal bars + connectors)
polar, gauge, sankey	WebGL-only

Revisit criteria

• [x] Line + candlestick parity
• [x] Boxplot + waterfall parity
• [x] No warning when WebGPU init succeeds
• [x] Fallback when navigator.gpu unavailable
• [ ] Benchmark ≥ WebGL FPS on discrete GPU (CI smoke only; desktop verify locally)
• [ ] Plot-area scissor + plotAreaBackground on WebGPU path

Related

• createChart renderer option
• Browser suite: /demos/stage1-benchmark.html