Describes a plane.
typedef struct D3DXPLANE { FLOAT a; FLOAT b; FLOAT c; FLOAT d; } D3DXPLANE, *LPD3DXPLANE;
The members of the D3DXPLANE structure take the form of the general plane equation. They fit into the general plane equation so that ax + by + cz + dw = 0.
C++ programmers can take advantage of operator overloading and type casting with the D3DXPLANE Extensions which implement overloaded constructors and assignment, unary, and binary (including equality) operators.