DirectX Color: Why can't it be a float?

Question

In my vertex declaration I can use various data types for color. Including:

• INT
• DWORD
• D3DCOLOR

I can't however use a float, it causes my shader to get the incorrect value.

I know an float is 4 bytes and so are all the other datatype I listed. So why does a float not work and the others do?

Answer 1

How would a single float represent the 4 (A,R,G,B) components? If you wonder how int does it, it packs 4 bytes within its 32bit (4 bytes) value.