| Microsoft DirectX 8.1 (Visual Basic) |
Computes the dot-product of a plane and a 4-D vector.
D3DXPlaneDot( _
P1 As D3DPLANE, _
P2 As D3DPLANE) As Single
The dot-product of the plane and 4-D vector.
If the function fails, an error is raised and Err.Number can be set to one of the following values.
| D3DERR_INVALIDCALL |
| D3DERR_OUTOFVIDEOMEMORY |
For information on trapping errors, see the Microsoft® Visual Basic® Error Handling topic.
Given a plane (a, b, c, d) and a 4-D vector (x, y, z, w) the return value of this function is a*x + b*y + c*z + d*w. The D3DXPlaneDot function is useful for determining the plane's relationship with a homogeneous coordinate. For example, this function could be used to determine if a particular coordinate is on a particular plane, or on which side of a particular plane a particular coordinate lies.