public bool Intersects(XMVector origin, XMVector direction, out float distance)
{
Debug.Assert(Internal.XMVector3IsUnit(direction), "Reviewed");
// Load the box.
XMVector v_center = this.center;
XMVector v_extents = this.extents;
// Adjust ray origin to be relative to center of the box.
XMVector t_origin = v_center - origin;
// Compute the dot product againt each axis of the box.
// Since the axii are (1,0,0), (0,1,0), (0,0,1) no computation is necessary.
XMVector axisDotOrigin = t_origin;
XMVector axisDotDirection = direction;
// if (fabs(AxisDotDirection) <= Epsilon) the ray is nearly parallel to the slab.
XMVector isParallel = XMVector.LessOrEqual(axisDotDirection.Abs(), CollisionGlobalConstants.RayEpsilon);
// Test against all three axii simultaneously.
XMVector inverseAxisDotDirection = axisDotDirection.Reciprocal();
XMVector t1 = (axisDotOrigin - v_extents) * inverseAxisDotDirection;
XMVector t2 = (axisDotOrigin + v_extents) * inverseAxisDotDirection;
// Compute the max of min(t1,t2) and the min of max(t1,t2) ensuring we don't
// use the results from any directions parallel to the slab.
XMVector t_min = XMVector.Select(XMVector.Min(t1, t2), CollisionGlobalConstants.FltMin, isParallel);
XMVector t_max = XMVector.Select(XMVector.Max(t1, t2), CollisionGlobalConstants.FltMax, isParallel);
// t_min.x = maximum( t_min.x, t_min.y, t_min.z );
// t_max.x = minimum( t_max.x, t_max.y, t_max.z );
t_min = XMVector.Max(t_min, XMVector.SplatY(t_min)); // x = max(x,y)
t_min = XMVector.Max(t_min, XMVector.SplatZ(t_min)); // x = max(max(x,y),z)
t_max = XMVector.Min(t_max, XMVector.SplatY(t_max)); // x = min(x,y)
t_max = XMVector.Min(t_max, XMVector.SplatZ(t_max)); // x = min(min(x,y),z)
// if ( t_min > t_max ) return false;
XMVector noIntersection = XMVector.Greater(XMVector.SplatX(t_min), XMVector.SplatX(t_max));
// if ( t_max < 0.0f ) return false;
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(XMVector.SplatX(t_max), XMGlobalConstants.Zero));
// if (IsParallel && (-Extents > AxisDotOrigin || Extents < AxisDotOrigin)) return false;
XMVector parallelOverlap = axisDotOrigin.InBounds(v_extents);
noIntersection = XMVector.OrInt(noIntersection, XMVector.AndComplementInt(isParallel, parallelOverlap));
if (!Internal.XMVector3AnyTrue(noIntersection))
{
// Store the x-component to *pDist
t_min.StoreFloat(out distance);
return(true);
}
distance = 0.0f;
return(false);
}
public static XMVector Ln(XMVector q)
{
XMVector oneMinusEpsilon = XMVector.FromFloat(1.0f - 0.00001f, 1.0f - 0.00001f, 1.0f - 0.00001f, 1.0f - 0.00001f);
XMVector qw = XMVector.SplatW(q);
XMVector q0 = XMVector.Select(XMGlobalConstants.Select1110, q, XMGlobalConstants.Select1110);
XMVector controlW = qw.InBounds(oneMinusEpsilon);
XMVector theta = qw.ACos();
XMVector sinTheta = theta.Sin();
XMVector s = XMVector.Divide(theta, sinTheta);
XMVector result = XMVector.Multiply(q0, s);
result = XMVector.Select(q0, result, controlW);
return(result);
}
