Mesh.IntersectSubset(Int32,Vector3,Vector3) Method (Microsoft.DirectX.Direct3D)
Intersects the specified ray with a given mesh subset.
Definition
Visual Basic Public Function IntersectSubset( _
ByVal attributeId As Integer, _
ByVal rayPos As Vector3, _
ByVal rayDir As Vector3 _
) As BooleanC# public bool IntersectSubset(
int attributeId,
Vector3 rayPos,
Vector3 rayDir
);C++ public:
bool IntersectSubset(
int attributeId,
Vector3 rayPos,
Vector3 rayDir
);JScript public function IntersectSubset(
attributeId : int,
rayPos : Vector3,
rayDir : Vector3
) : boolean;
Parameters
attributeId System.Int32
Attribute identifier of the subset to intersect with.rayPos Microsoft.DirectX.Vector3
A Vector3 structure that specifies the origin coordinate of the ray.rayDir Microsoft.DirectX.Vector3
A Vector3 structure that specifies the direction of the ray.
Return Value
System.Boolean
Value that is true if the ray intersects a triangular face on the mesh; otherwise, the value is false.
Remarks
This method provides functionality that is similar to that of Intersect.
The IntersectSubset method provides a way to understand points in and around a triangle, independent of where the triangle is actually located. This method returns the resulting point by using the following equation:
V1 + U(V2-V1) + V(V3-V1)
Any point in the plane V1V2V3 can be represented by the barycentric coordinate (U,V). The U parameter controls how much V2 gets weighted into the result, and the V parameter controls how much V3 gets weighted into the result. Lastly, 1-U-V controls how much V1 gets weighted into the result.
Barycentric coordinates are a form of general coordinates. In this context, using them represents a change in coordinate systems. What holds true for Cartesian coordinates also holds true for barycentric coordinates.
Exceptions
The method call is invalid. For example, a method's parameter might contain an invalid value.
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Microsoft Direct3D could not allocate sufficient memory to complete the call.