• Alexandr Druzhinin (11/11) Oct 24 2013 May I cast like:
• Dicebot (7/18) Oct 24 2013 Not entirely. Try adding `align(64)` to struct declaration and
• Adam D. Ruppe (24/25) Oct 24 2013 Two options would be to make the points itself be a float[] with
• Alexandr Druzhinin (3/26) Oct 24 2013 I thought to use union, but using struct with properties is good to

Alexandr Druzhinin <drug2004 bk.ru> writes:

May I cast like:

struct Point
{
	float x, y, z;
	float r, g, b, a;
}

Point[] points;

void foo(float[] float_array) {};

foo(cast(float[]) points); // is it safe?

May be more elegant way do express this exists?

Thanks

"Dicebot" <public dicebot.lv> writes:

On Thursday, 24 October 2013 at 17:59:03 UTC, Alexandr Druzhinin 
wrote:
 May I cast like:

 struct Point
 {
 	float x, y, z;
 	float r, g, b, a;
 }

 Point[] points;

 void foo(float[] float_array) {};

 foo(cast(float[]) points); // is it safe?

 May be more elegant way do express this exists?

 Thanks

Not entirely. Try adding `align(64)` to struct declaration and 
observe funny change ;) It is clearly some low-level hack and not 
something for usage in normal code.

One can create array from struct instance via [ point.tupleof ], 
but this will allocate as all array literals do.

"Adam D. Ruppe" <destructionator gmail.com> writes:

On Thursday, 24 October 2013 at 17:59:03 UTC, Alexandr Druzhinin 
wrote:
 foo(cast(float[]) points); // is it safe?

Two options would be to make the points itself be a float[] with 
the names just properties into the index:

struct Point {
  float[7] data;
  ref float x() { return data[0]; }
  ref float y() { return data[1]; }
  // etc etc etc
}

then to use it, just pass point.data[] instead of casting.

Or you could also do a union:

struct Point {
    union {
       float[7] data;
       struct {
          float x,y,z,r,g,b,a;
       }
    }
}

and again, pass point.data[] instead of casting it, while 
continuing to use the other members normally.

These are both well defined so are less likely to break than the 
cast.

Alexandr Druzhinin <drug2004 bk.ru> writes:

25.10.2013 02:08, Adam D. Ruppe пишет:
 On Thursday, 24 October 2013 at 17:59:03 UTC, Alexandr Druzhinin wrote:
 foo(cast(float[]) points); // is it safe?

 Two options would be to make the points itself be a float[] with the
 names just properties into the index:

 struct Point {
   float[7] data;
   ref float x() { return data[0]; }
   ref float y() { return data[1]; }
   // etc etc etc
 }

 then to use it, just pass point.data[] instead of casting.

 Or you could also do a union:

 struct Point {
     union {
        float[7] data;
        struct {
           float x,y,z,r,g,b,a;
        }
     }
 }

 and again, pass point.data[] instead of casting it, while continuing to
 use the other members normally.

 These are both well defined so are less likely to break than the cast.

I thought to use union, but using struct with properties is good to 
know. Thanks for sharing!