javagl.github.io
GLConstantsTranslator : A utility to translate between OpenGL constant names and their hexadecimal and decimal representations
MetallicRoughnessCreator : A utility to combine a "metallic" texture and a "roughness" texture into a "metallic and roughness" texture as it is required for PBR in glTF
Disclaimer:
These are utilities intended for personal use, and I'm not a JavaScript- HTML or CSS expert, so they are probably poorly implemented. Improvements via pull requests are welcome. Issues may be ignored.