[vtkusers] Design Gripes

[Rasmus Reinhold Paulsen]

Hi Murad,

I think that you have some good points, but some of your observations are
and have been discussed in detail especially among the developers. Being a
newbie myself I have also wondered why templates and the standard template
library was not used more, but there are some heavyweight arguments
against it; one of them is that wrapping of templated code is difficult at
best.
I suggest you to dive into the developer list archives and search for
articles about containers. I believe that a standard container hierachy is
currently being implemented and tested in VTK.

Regards
Rasmus

On Thu, 28 Mar 2002, Murad Nayal wrote:

> I have been studying vtk4 for a while and I must admit I am finding the
> design frustrating. I understand the argument that object oriented
> design principles have to yield to performance considerations when
> programming visualization applications. I am also aware that the authors
> have opted not to use advanced features of C++ like templates when these
> features were not uniformly available in C++ compilers several years
> ago. but at this point in time does it still make sense to have 5 or 6
> implementations of data arrays differing by the underlying data type
> rather than use templates. wouldn't be nice to use the notion of a class
> Vector3D {float x,y,z; } instead of all the silly float xyz[3] arrays
> used everywhere. I highly doubt that performance will degrade by using a
> Vector3D class. Also, it would be really nice if call back functions
> were function objects that can maintain state. programming with function
> pointers like void (*)(void*) and associated argument delete functions
> seems clunky at best. I know there are constraints related to the
> underlying graphics libraries. but this still could be implemented with
> no more than an additional indirect function call overhead. would that
> be so bad for performance? etc..