UUID normalization
Input is trimmed, hyphens are removed, hexadecimal letters are normalized, and the remaining value must contain exactly 32 hexadecimal digits. The canonical display form is 8-4-4-4-12 characters.
Username input is resolved through a server-side provider adapter. The browser receives the public profile name and UUID; the actual color calculation then happens locally.
Default color algorithm
The normalized 128-bit UUID is split into Java's most- and least-significant 64-bit values. Their XOR is folded into Java UUID.hashCode(). The low red, green, and blue bytes are then multiplied by the 1.21.6 renderer's 0.9 shade factor and truncated like Java float-to-int conversion.
This last shade step matters: returning the raw low 24 hash bits is close, but it does not exactly match the rendered default marker.
Verification and limits
Automated vectors cover nil, maximum, mixed-case, hyphenated, compact, versioned, and high-bit UUIDs. Tests compare normalization, Java hash behavior, RGB output, and equivalent input forms.
The result is the fallback color for a UUID waypoint. Team colors, explicit /waypoint color commands, plugins, resource packs, and future game changes can alter what players see.
- Minecraft source checked: official Java 1.21.6 client mappings and bytecode for LocatorBarRenderer and ARGB.
- Comparison model: CIE Lab Euclidean distance with a centrally configured usability threshold.
- No claim is made for Bedrock default color calculation.