Re: [boost] Geometry/Vec lib swizzle syntax prototype

From: Michael Marcin (mmarcin_at_[hidden])
Date: 2006-12-01 16:47:23

Michael Fawcett wrote:
> I have uploaded a small prototype that demonstrates the syntax
> mentioned in the thread below.  It is in the Vault under Math -
> Geometry as swizzle_demo.zip.
>
> http://article.gmane.org/gmane.comp.lib.boost.devel/149076/match=geometry+vector+lib+swizzle
>
> Here's a small example showing its use:
>
> float4 b(1, 2, 3, 4);
>
> float4 a = b.xxxx(); // a is now 1, 1, 1, 1
> a = b.wwwz(); // a is now 4, 4, 4, 3
> a = b.yzzw(); // a is now 2, 3, 3, 4
> a = b.wzyx(); // a is now 4, 3, 2, 1
>
> float4 c(10, 20, 30, 40);
> c.yz() = b.zy(); // c is now 10, 3, 2, 40
>
>  <snip>
>

Very cool!  I know nothing about the PP library so it is very hard for me to 
decipher what the code is doing.
If I were to write:

float4 red( 1, 0, 0, 1 );
glColor4fv( (float*)&red ); // make color red
glColor4fv( (float*)&red.xxxw() ); // make color white

would this work?  I'm guessing red would and white would not.

Thanks,

Michael Marcin