How do you reflect and object on a plane?

[GraphicsProgrammer3]

I have been asked to reflect an object about the plane z = 1.

I have attempted this with the following code.

D3DXMatrixReflect (&m_matWorld, D3DXPlane(0.0,0.0,1.0f) );

but the D3DXPlane identifier isn't found. First of all I would like to know if this is what I need and if it is then where should be defined?

If im totally wrong here let me know. If I find a solution to this before an answer is given. I will post what I did to prevent others from getting this problem.

[OReubens]

it's D3DXPLANE (all capitals) unless you have some specific library/class in use.
The source plane needs to be a pointer.

Assuming you have the C++ extensions enabled in DX:

D3DXPLANE z1(0.0, 0.0, 1.0, 0.0); 
D3DXMatrixReflect (&m_matWorld, &z1 );

Whether this is what you're after is another matter.

[GraphicsProgrammer3]

It look like the right thing. I am transforming between model to world and have the translate matrices already. I was just unsure about that section.

I will try what you have mentioned and see if it is fixed.

Thanks alot