fix: return fallback color for malformed hex instead of NaN

[codergon]

Summary

getShaderColorFromString returns NaN color channels for malformed hex strings instead of falling back to a valid color. Those NaNs get uploaded as GPU color uniforms, which produces broken/undefined rendering for the affected shader.

The function already has a fallback contract for unparseable input — the existing test asserts getShaderColorFromString('not-a-color') → [0, 0, 0, 1]. Hex strings just weren't held to it: any hex with invalid characters or an invalid length slipped through to parseInt, yielding NaN.

getShaderColorFromString('#gggggg'); // [NaN, NaN, NaN, 1]
getShaderColorFromString('#12345');  // [0.07, 0.20, 0.01, NaN]
getShaderColorFromString('#ff');     // [1, NaN, NaN, NaN]

Changes

• Validate hex after expansion. If the normalized value isn't exactly 8 hex digits, return the fallback color ([0, 0, 0, 1]) — matching how other unparseable input is already handled — instead of emitting NaN.
• Support 4-digit #rgba shorthand. This is valid CSS that the parser previously mangled into NaN (it only expanded 3- and 6-digit forms). Expanding it alongside the 3-digit case also keeps the new validation from wrongly rejecting a valid color.

getShaderColorFromString('#gggggg'); // [0, 0, 0, 1]  ← fallback
getShaderColorFromString('#12345');  // [0, 0, 0, 1]  ← fallback
getShaderColorFromString('#ff');     // [0, 0, 0, 1]  ← fallback
getShaderColorFromString('#ff0c');   // [1, 1, 0, 0.8] ← 4-digit shorthand now supported

Test plan

• Added cases to get-shader-color-from-string.test.ts:
  • 4-digit hex with alpha (#ff0c → [1, 1, 0, 0.8])
  • hex with invalid characters returns fallback (#gggggg)
  • hex with invalid length returns fallback (#12345, #ff)
• bun test passes (new cases green, no regressions).
• bun run build and type-check pass; Prettier clean.

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Project	Deployment	Actions	Updated (UTC)
shaders-docs	Ready	Preview, Comment	Jul 6, 2026 5:05pm