digitalmars.D - I wish I could inherit structs.
- Jarrett Billingsley (17/17) May 16 2005 This is quite an interesting problem.
- Andrew Fedoniouk (17/37) May 16 2005 I would suggest something like this:
- Mike Parker (16/40) May 16 2005 template mixD3DXFRAME()
- Ben Hinkle (11/30) May 16 2005 old-school "inheritance":
- Jarrett Billingsley (3/4) May 18 2005 I'll try one of these solutions until (if) a real one comes. Thanks guy...
This is quite an interesting problem. In the DirectX SDK, there is a structure called D3DXFRAME. This simply holds some data members that describe a link in a 3D hierarchy. It doesn't really matter what it does; all it matters is that it's a struct. Now, here's the thing. This struct _must_ be a struct, as the data members cannot be moved around or realigned. This is because the internal workings of some of the SDK functions rely on the members being in certain places. But at the same time, I need to be able to derive from this struct so I can add my own custom data to it. Which is currently impossible. The SDK was designed with C++ in mind, which can do this. The worst part is that there isn't really a workaround. I can't make the D3DXFRAME a class as there is no guarantee that the members will stay in the same order/alignment. I can't make a parallel class that holds the extra data as there is no place for me to put a reference to the class instance in the D3DXFRAME structure. About the only thing I _could_ do is to keep an associative array indexed by D3DXFRAME pointers. And that's just nasty. I'm.. stumped.
May 16 2005
"Andrew Fedoniouk" <news terrainformatica.com>
I would suggest something like this:
template D3DXFRAME(S)
{
LPSTR Name;
D3DXMATRIX TransformationMatrix;
D3DXMESHCONTAINER* pMeshContainer;
S *pFrameSibling;
S *pFrameFirstChild;
}
align(X) struct MyD3DXFRAME
{
mixin D3DXFRAME!(MyD3DXFRAME);
//your own stuff goes here....
}
Andrew.
"Jarrett Billingsley" <kb3ctd2 yahoo.com> wrote in message
news:d6bhag$2ve4$1 digitaldaemon.com...
This is quite an interesting problem.
In the DirectX SDK, there is a structure called D3DXFRAME. This simply
holds some data members that describe a link in a 3D hierarchy. It
doesn't really matter what it does; all it matters is that it's a struct.
Now, here's the thing. This struct _must_ be a struct, as the data
members cannot be moved around or realigned. This is because the internal
workings of some of the SDK functions rely on the members being in certain
places.
But at the same time, I need to be able to derive from this struct so I
can add my own custom data to it. Which is currently impossible. The SDK
was designed with C++ in mind, which can do this.
The worst part is that there isn't really a workaround. I can't make the
D3DXFRAME a class as there is no guarantee that the members will stay in
the same order/alignment. I can't make a parallel class that holds the
extra data as there is no place for me to put a reference to the class
instance in the D3DXFRAME structure. About the only thing I _could_ do is
to keep an associative array indexed by D3DXFRAME pointers. And that's
just nasty.
I'm.. stumped.
May 16 2005
Jarrett Billingsley wrote:This is quite an interesting problem. In the DirectX SDK, there is a structure called D3DXFRAME. This simply holds some data members that describe a link in a 3D hierarchy. It doesn't really matter what it does; all it matters is that it's a struct. Now, here's the thing. This struct _must_ be a struct, as the data members cannot be moved around or realigned. This is because the internal workings of some of the SDK functions rely on the members being in certain places. But at the same time, I need to be able to derive from this struct so I can add my own custom data to it. Which is currently impossible. The SDK was designed with C++ in mind, which can do this. The worst part is that there isn't really a workaround. I can't make the D3DXFRAME a class as there is no guarantee that the members will stay in the same order/alignment. I can't make a parallel class that holds the extra data as there is no place for me to put a reference to the class instance in the D3DXFRAME structure. About the only thing I _could_ do is to keep an associative array indexed by D3DXFRAME pointers. And that's just nasty. I'm.. stumped.template mixD3DXFRAME() { float memberOne; float memberTwo; } struct D3DXFRAME { mixin mixD3DXFRAME; } struct Inherited { mixin mixD3DXFRAME; float memberThree; } Does this solve it?
May 16 2005
"Jarrett Billingsley" <kb3ctd2 yahoo.com> wrote in message news:d6bhag$2ve4$1 digitaldaemon.com...This is quite an interesting problem. In the DirectX SDK, there is a structure called D3DXFRAME. This simply holds some data members that describe a link in a 3D hierarchy. It doesn't really matter what it does; all it matters is that it's a struct. Now, here's the thing. This struct _must_ be a struct, as the data members cannot be moved around or realigned. This is because the internal workings of some of the SDK functions rely on the members being in certain places. But at the same time, I need to be able to derive from this struct so I can add my own custom data to it. Which is currently impossible. The SDK was designed with C++ in mind, which can do this. The worst part is that there isn't really a workaround. I can't make the D3DXFRAME a class as there is no guarantee that the members will stay in the same order/alignment. I can't make a parallel class that holds the extra data as there is no place for me to put a reference to the class instance in the D3DXFRAME structure. About the only thing I _could_ do is to keep an associative array indexed by D3DXFRAME pointers. And that's just nasty. I'm.. stumped.old-school "inheritance": struct D3DXFRAME { ... } struct MyDXFrame { D3DXFRAME native; int whatever; ... } when calling a "native" OS function that takes a D3DXFRAME pass it the native member.
May 16 2005
"Jarrett Billingsley" <kb3ctd2 yahoo.com> wrote in message news:d6bhag$2ve4$1 digitaldaemon.com...I'm.. stumped.I'll try one of these solutions until (if) a real one comes. Thanks guys :)
May 18 2005