Re: [Algorithms] View Frustum Culling 1 week on

[Felix F. <fe...@am...>]

Hi,

> But D3DXVec3Transform  may not have a valid w value after projecting -
> how could it know that there was space for the w value if it expects a
> Vec3.

I assume this because the DirectX8 documentation says:

	D3DXVECTOR4* D3DXVec3Transform(D3DXVECTOR4* pOut,
		CONST D3DXVECTOR3* pV, CONST D3DXMATRIX* pM); 

	Parameters:
	pOut
		[in, out] Pointer to the D3DXVECTOR4 structure that is the 
result of the operation. 
	pV 
		[in] Pointer to the source D3DXVECTOR3 structure. 
	pM 
		[in] Pointer to the source D3DXMATRIX structure. 

	...

	Remarks:
	This function transforms the vector, pV (x, y, z, 1), by the 
matrix, pM.
	...


And, after all, if it does not knows the w value from the source 
vector, why is it dumping the output into a D3DXVECTOR4 vector 
and not into a D3DXVECTOR3? (I assume that D3DX8 was logical 
bulit ;-) )

-felix