I like the ptr++ for-loop I must say - I get the impression it'd be fast, and it's pretty to look at, but it wouldn't let me cast with static_cast or (float*) -c-style cast, to cast the struct of floats to a (float*) - is this something to do with the virtual function table of the struct Colour ( since it has constructor, copy constructor, and a method) ? This is where a dynamic_cast comes in? And I don't really need it to be doing a dynamic cast, right?
No, it has nothing to do with virtual function tables or dynamic_cast. It's because colour is a struct and (float*) is a pointer. If you really want to do this cast, the C-style cast or a reinterpret_cast should work on the address of colour, (&colour), though I don't really recommend doing this. You could use a union inside colour if you want it to have 4 floats that are also used as an array.
