Horde3D

Hey guys,
i'm using the .NET wrapper for horde. I want to use the getNodeTransformMatrices function to save a transform matrix in my own c#-matrix class.

In C++, this would be easy by saving the returned matrix in a Pointer, which could be used as a 2-dimensional float-pointer - you can use this pointer at once as a matrix type. I'm not a good C++-programmer (thats why i use the .net-wrapper), but our prof gave us this solution how to handle the matrix in C++:


In the C#-Wrapper, the getNodeTransformMatrices needs a struct of the type IntPtr to save its values to.

Now i have the matrix returned by horde in one Intpointer. I found out that the size of this pointer (returned by Marshal.SizeOf(hordePointer) is 4.
So i guess this Intpointer points itself to 4 Intpointers. Each of this Intpointers should contain 4 float values, that represent the Transformation Matrix.

Now i have 4 Intpointers. My problem now: how do i extract the 4 float values out of each intpointer? I guess i'm not far away from a solution... Anyone here good some experience in handling pointers in C#?

Thanks very much in advance for your help!

Well, I'm just guessing here as I don't have a compiler available right now... but the sizeof function most likely gives you the size in BYTES (like the C sizeof function). 4 bytes is the pointer size on 32bit Windows. So the IntPtr probably points to the first element of the matrix. Since you know it's a matrix with 16 floats, you should be able to get all values using the returned IntPtr.

By the way, I think you might be confused by the naming of IntPtr. It does not mean (in C-syntax) int*. An IntPtr is just a wrapper around a pointer and its size is 32bits (4bytes) on 32bit systems and 64bit (8bytes) on 64 bit systems. Maybe the MSDN article helps you: http://msdn.microsoft.com/en-us/library ... tptr(VS.90).aspx

yeah thats right, thank you, of course its 4 bytes - my fault...
But i still don't know how to access the elements of this intPtr, although i know it has 16 elements.
What i have now:



this gives me the output


Seems to me like he returns memory addresses? Anyone knows how i can get the floats out of this?

Does that post help you?

Thank you, but no that post also didn't help.
Maybe my question is more related to C#-development and Pointers in C# in common, so i posted my question in a C#-Forum. I hope i'm getting a working solution soon, when i do i'll post it here.

what a fight! After a long discussion in a c#-forum, i got a working solution!
Here it is:



Now i can save the horde-matrix in my own c#-matrix-class.

in case that any c#-horde developer will stumble over this post:

I managed a good way to handle the matrices from horde in C#.
A good (and simple but not too simple) matrix library for C# is the DotNetMatrix:
http://www.codeproject.com/KB/recipes/psdotnetmatrix.aspx

I use this library for my matrix-ops.
I convert the matrix i get from getNodeTransformMatrices with this function:



To push the changes you make in the matrix back to horde (e.g. setNodeTransformMatrix) i wrote this function to convert the generalmatrix to a float[] (needed by the c#-wrapper-functions):



Maybe my approach is not the fastest and best, but if i wanted something fast i would rather use C++