Hi,

I'm trying to make a const function returning a float[3] array with the position of my camera.

But I can't manage to do this, without passing the array as a function parameter.

To be exact, this is what I do now:

void CD3dcam::GetPositionF(float pPos[]) const
{
	pPos[0] = mPosition.x;
	pPos[1] = mPosition.y;
	pPos[2] = mPosition.z;
}

But this is ofcourse annoying if I want to pass GetPositionF to a function as a parameter, where a float array is expected.

So I tried something like

float* CD3dcam::GetPositionF() const

{

float pos[3];

pos[0] = mPosition.x;

pos[1] = mPosition.y;

pos[2] = mPosition.z;

return pos;

}

This compiles, but gives a warning that I'm returning the address of a local variable in memory, instead of a pointer to the actual values.

Any ideas anyone?

Update;

This seems to work, not sure though if it's correct:

float* CD3dcam::GetPositionF() const
{
	float *pos = new float[3];

	pos[0] = mPosition.x;
	pos[1] = mPosition.y;
	pos[2] = mPosition.z;

	return pos;
}

You can return a struct (by value, i.e. not via a pointer to the struct) which has a float[3] as its only member as well if you really want to return the array. This may copy but the compiler should be able to optimise the copy out.

Don't return the address of a global variable, it doesn't scale well (meaning: doesn't scale at all) if you need to call it recursively or on multiple threads.

EDIT: I see Alvaro suggested making a Point class, missed that, it's the same as what I suggested using a class instead of a struct.

Thanks.

I'm not sure though if making a struct will bring me what I'm looking for.

The function I have to pass the float array too, expects a pointer array:

HRESULT SetFloatArray(
[in] D3DXHANDLE hParameter,
[in] const FLOAT *pf,
[in] UINT Count
);

That would mean that I have to create a local object of the struct in every frame, filling it with GetPositionF and passing the member of the object to the function above.

Sounds a bit 'waste', although I don't know how to do it easier.

Make mPosition a union? Of a float[3] array and float x, y, z; Then just pass &mPosition directly.

I 'solved' it now by making a public member float array: mPosF[3] and update it when the camera moves.

And in the SetFloatArray I just call that public member of my camera class.

This works for now, still not sure if there's a better way though.

Paradigm shifter: that's sort of what I did now, I think :)