Dynamic physical ocean

I’m working on the math model and I wrote out all the code which gives me a bunch of undeclared identifiers for “Texture” and “CalculateGerstnerWave” identifier not found. If I follow the buoyancy video will I set up those identifiers there? Or did I just mess up writing the code? Which I doubt because I reviewed my code to yours a thousand times. Or is there something in the header I missed?