Function directx_math::XMQuaternionBaryCentric [−][src]
pub fn XMQuaternionBaryCentric(
Q0: FXMVECTOR,
Q1: FXMVECTOR,
Q2: FXMVECTOR,
f: f32,
g: f32
) -> XMVECTOR
Returns a point in barycentric coordinates, using the specified quaternions.
Parameters
Q0 First quaternion in the triangle.
Q1 Second quaternion in the triangle.
Q2 Third quaternion in the triangle.
f Weighting factor. See the remarks.
g Weighting factor. See the remarks.
Return value
Returns a quaternion in barycentric coordinates.
Remarks
The following pseudocode demonstrates the operation of the function.
XMVECTOR Result;
XMVECTOR QA, QB;
float s = f + g;
if (s != 0.0f)
{
QA = XMQuaternionSlerp(Q0, Q1, s);
QB = XMQuaternionSlerp(Q0, Q2, s);
Result = XMQuaternionSlerp(QA, QB, g / s);
}
else
{
Result.x = Q0.x;
Result.y = Q0.y;
Result.z = Q0.z;
Result.w = Q0.w;
}
return Result;
Note that Barycentric coordinates work for ‘flat’ surfaces but not for ‘curved’ ones. This function is therefore a bit of a work-around. An alternative method for blending 3 quanterions is given by the following code:
inline XMVECTOR XMQuaternionBlend(
FXMVECTOR Q0,
FXMVECTOR Q1,
FXMVECTOR Q2,
float w1,
float w2
)
{
// Note if you choose one of the three weights to be zero, you get a blend of two
// quaternions. This does not give you slerp of those quaternions.
float w0 = 1.0f - w1 - w2;
XMVECTOR Result = XMVector4Normalize(
XMVectorScale(Q0, w0) +
XMVectorScale(Q1, w1) +
XMVectorScale(Q2, w2));
return Result;
}