D3DXQuaternionBaryCentric

Returns a quaternion in barycentric coordinates.

D3DXQUATERNION * D3DXQuaternionBaryCentric(
  D3DXQUATERNION * pOut,
  CONST D3DXQUATERNION * pQ1,
  CONST D3DXQUATERNION * pQ2,
  CONST D3DXQUATERNION * pQ3,
  FLOAT f,
  FLOAT g
);

Parameters

pOut

[in, out] Pointer to the D3DXQUATERNION structure that is the result of the operation.

pQ1

[in] Pointer to a source D3DXQUATERNION structure.

pQ2

[in] Pointer to a source D3DXQUATERNION structure.

pQ3

[in] Pointer to a source D3DXQUATERNION structure.

f

[in] Weighting factor. See Remarks.

g

[in] Weighting factor. See Remarks.

Return Values

Pointer to a D3DXQUATERNION structure in Barycentric coordinates.

Remarks

To compute the barycentric coordinates, the D3DXQuaternionBaryCentric function implements the following series of spherical linear interpolation operations:

Slerp(Slerp(Q1, Q2, f+g), Slerp(Q1, Q3, f+g), g/(f+g))

The return value for this function is the same value returned in the pOut parameter. In this way, the D3DXQuaternionBaryCentric function can be used as a parameter for another function.

Use D3DXQuaternionNormalize for any quaternion input that is not already normalized.

Barycentric coordinates define a point inside a triangle in terms of the triangle's vertices. For a more in-depth description of barycentric coordinates, see Mathworld's Barycentric Coordinates Description.

Requirements

Header: Declared in D3dx9math.h.