[vtkusers] c# port of VTK

[Andy Somogyi]

Hello VTK users

I am in the process of completly porting VTK (4.2) to c#.
As this is c#, it can be used nativly from any .net language.

When finished, it will be freely availble under the existing VTL lisence.

My question is this:

The c++ version of VTK uses length 3 arrays to represent a vector in 3 space.
This is fine in c++ because you can create arrays on the stack.

It is not possible to create a managed array in c# on the stack, they are allways
heap allocated and garbage collected. So using a large number of managed arrays, or
creating large numbers of transitory arrays is very inefficient.

The use of a 'value type' or a 'struct' in other words is far more effcient when
large numbers of objects are involved as they are created on the stack and are not
garbage collected.

I have thought about using a raw double pointer (double*) instead of an managed array
for all functions that use a vector (double[3]). This has the advantage of being very
fast, but on the other hand, it is highly error prone, and a user of one of these functions
must declare thier method 'unsafe'. I would suspsct that this would discourage many users.

There are many good vector and matrix classes avaible for .net, such as the standard vector and
matrix types that ship with directx 9.

So my question to any perspective vtk.net users is would you prefer all existing methods
that currently accept a c++ style array (double[3]) accept the following in the new
c# port:

1: managed array (new double[3])
     advantages:
     1.1 farmiliar syntax
     1.2 do not have to declare 'unsafe' code
     disadvanteges:
     1.2 very ineffcient both in terms of size and performance

2: unmanaged pointer (double*)
     advanteges:
     2.1 very effecient
     disadvantes:
     2.2 error prone
     2.3 need to pin a managed array or use 'stackalloc'

3: use a 'Vector3' value type
     advanteges
     3.1 very effcient
     3.2 very safe
     3.3 easy to convert to and from a 'double*'
     disadvantes:
     3.3 introduces unfarmiliair syntax

Any ides or oppinions would be greatly appcieated

thanks