[vtkusers] c# port of VTK

[Sean McInerney]

Andy,

   I am sure that a C# port could be very popular. Are you using a 
wrapping approach or are you parsing C++ code to generate C#?

   Also, I am unsure of where you are encountering the problem that you 
describe in your message. Could you provide a few specific instances?

-Sean

Andy Somogyi wrote:
> 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
> 
> 
> 
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