[codex] reuse registered shaders across engines

[cptbtptpbcptdtptp]

Summary

• reuse globally registered Shader descriptors only when a new Engine ResourceManager reloads the same URL and exact ShaderLab source or precompiled .shaderc content
• reject same-name shaders when their recorded URL or source content differs, or when the existing shader has no loader provenance
• make duplicate Shader.create and _createFromPrecompiled calls return the registered Shader instead of undefined
• add a browser regression test that compiles a Shader, destroys the first Engine, recreates an Engine on the same canvas, reloads the assets, and compiles again

Problem

Shader descriptors live in a global name registry, while every Engine owns an independent ResourceManager cache. After an Engine is destroyed, a new Engine loading the same shader asset reaches Shader.create again. The duplicate-name branch previously returned undefined; ResourceManager then tried to cache that value and accessed instanceId, turning an expected descriptor reuse into a loading failure.

GPU Shader Programs are still scoped to their Engine/WebGL context. Engine.destroy() clears the destroyed Engine's program maps, and the reused Shader descriptor creates a new program when compiled by the next Engine.

The loader records the original URL and source string in a WeakMap keyed by Shader. This keeps exact comparison off the render loop and preserves the previous duplicate-name conflict behavior for different projects that happen to use the same shader name.

Verification

• pnpm run b:module
• pnpm run b:types
• pnpm exec vitest run tests/src/loader/ShaderLoader.test.ts tests/src/core/Shader.test.ts tests/src/core/resource/ResourceManager.test.ts --browser.headless (30 tests passed)
• repository pre-commit ESLint and Prettier hooks

[coderabbitai]

Important

Review skipped

Draft detected.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 29c1116d-1d61-4c52-b06c-db347aec9423

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}