Re: [Glsdk-devel] The use of anonymous structures

[Stefanos A. <sta...@gm...>]

Την Sun, 24 Aug 2008 04:05:06 +0300,ο(η) Henri Häkkinen  
<hen...@gm...> έγραψε:

> Does anyone have anything to say on this, please? I am currently working
> hard on the GLM and I think we should resolve the issue of how we  
> actually
> define the math types.
>

I'd go for #2 (struct/union), just slightly modified.

Why use a struct? Because typing vec.x is cleaner than vec[0].

Why have a union? So you can pass the struct to OpenGL without a cast.  
Compare:

foo(vec.data);	     // approach #2 (struct/union)
vs
foo((GLfloat*)vec);  // approach #3 (struct)
vs
foo(&vec.x);         // approach #3 (struct)

To that end, it might be better to define structs like this:

typedef struct GLMFoo_t
{
     union GLMFoo_data
     {
         GLfloat data[2];   // Instead of v[] or m[]
         struct GLMFoo_fields
         {
             GLfloat x, y;
         }
     }
} GLMFoo;

This makes clear that the "data" field provides the storage for the vector  
data - v or m might be somewhat cryptic at first glance.