public bool Intersects(XMVector origin, XMVector direction, out float distance)
{
Debug.Assert(Internal.XMVector3IsUnit(direction), "Reviewed");
XMVector v_center = this.center;
XMVector v_radius = XMVector.Replicate(this.radius);
// l is the vector from the ray origin to the center of the sphere.
XMVector l = v_center - origin;
// s is the projection of the l onto the ray direction.
XMVector s = XMVector3.Dot(l, direction);
XMVector l2 = XMVector3.Dot(l, l);
XMVector r2 = v_radius * v_radius;
// m2 is squared distance from the center of the sphere to the projection.
XMVector m2 = l2 - (s * s);
XMVector noIntersection;
// If the ray origin is outside the sphere and the center of the sphere is
// behind the ray origin there is no intersection.
noIntersection = XMVector.AndInt(XMVector.Less(s, XMGlobalConstants.Zero), XMVector.Greater(l2, r2));
// If the squared distance from the center of the sphere to the projection
// is greater than the radius squared the ray will miss the sphere.
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(m2, r2));
// The ray hits the sphere, compute the nearest intersection point.
XMVector q = (r2 - m2).Sqrt();
XMVector t1 = s - q;
XMVector t2 = s + q;
XMVector originInside = XMVector.LessOrEqual(l2, r2);
XMVector t = XMVector.Select(t1, t2, originInside);
if (XMVector4.NotEqualInt(noIntersection, XMVector.TrueInt))
{
// Store the x-component to *pDist.
t.StoreFloat(out distance);
return(true);
}
distance = 0.0f;
return(false);
}
public bool Intersects(XMVector v0, XMVector v1, XMVector v2)
{
XMVector zero = XMGlobalConstants.Zero;
// Load the box.
XMVector v_center = this.center;
XMVector v_extents = this.extents;
XMVector boxMin = v_center - v_extents;
XMVector boxMax = v_center + v_extents;
// Test the axes of the box (in effect test the AAB against the minimal AAB
// around the triangle).
XMVector triMin = XMVector.Min(XMVector.Min(v0, v1), v2);
XMVector triMax = XMVector.Max(XMVector.Max(v0, v1), v2);
// for each i in (x, y, z) if a_min(i) > b_max(i) or b_min(i) > a_max(i) then disjoint
XMVector disjoint = XMVector.OrInt(XMVector.Greater(triMin, boxMax), XMVector.Greater(boxMin, triMax));
if (Internal.XMVector3AnyTrue(disjoint))
{
return(false);
}
// Test the plane of the triangle.
XMVector normal = XMVector3.Cross(v1 - v0, v2 - v0);
XMVector dist = XMVector3.Dot(normal, v0);
// Assert that the triangle is not degenerate.
Debug.Assert(!XMVector3.Equal(normal, zero), "Reviewed");
// for each i in (x, y, z) if n(i) >= 0 then v_min(i)=b_min(i), v_max(i)=b_max(i)
// else v_min(i)=b_max(i), v_max(i)=b_min(i)
XMVector normalSelect = XMVector.Greater(normal, zero);
XMVector v_min = XMVector.Select(boxMax, boxMin, normalSelect);
XMVector v_max = XMVector.Select(boxMin, boxMax, normalSelect);
// if n dot v_min + d > 0 || n dot v_max + d < 0 then disjoint
XMVector minDist = XMVector3.Dot(v_min, normal);
XMVector maxDist = XMVector3.Dot(v_max, normal);
XMVector noIntersection = XMVector.Greater(minDist, dist);
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(maxDist, dist));
// Move the box center to zero to simplify the following tests.
XMVector tV0 = v0 - v_center;
XMVector tV1 = v1 - v_center;
XMVector tV2 = v2 - v_center;
// Test the edge/edge axes (3*3).
XMVector e0 = tV1 - tV0;
XMVector e1 = tV2 - tV1;
XMVector e2 = tV0 - tV2;
// Make w zero.
e0.W = zero.W;
e1.W = zero.W;
e2.W = zero.W;
XMVector axis;
XMVector p0, p1, p2;
XMVector min, max;
XMVector radius;
//// Axis == (1,0,0) x e0 = (0, -e0.z, e0.y)
axis = new XMVector(e1.W, -e0.Z, e1.Y, e1.X);
p0 = XMVector3.Dot(tV0, axis);
//// p1 = XMVector3Dot( V1, Axis ); // p1 = p0;
p2 = XMVector3.Dot(tV2, axis);
min = XMVector.Min(p0, p2);
max = XMVector.Max(p0, p2);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
//// Axis == (1,0,0) x e1 = (0, -e1.z, e1.y)
axis = new XMVector(e1.W, -e1.Z, e1.Y, e1.X);
p0 = XMVector3.Dot(tV0, axis);
p1 = XMVector3.Dot(tV1, axis);
//// p2 = XMVector3Dot( V2, Axis ); // p2 = p1;
min = XMVector.Min(p0, p1);
max = XMVector.Max(p0, p1);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
//// Axis == (1,0,0) x e2 = (0, -e2.z, e2.y)
axis = new XMVector(e2.W, -e2.Z, e2.Y, e2.X);
p0 = XMVector3.Dot(tV0, axis);
p1 = XMVector3.Dot(tV1, axis);
//// p2 = XMVector3Dot( V2, Axis ); // p2 = p0;
min = XMVector.Min(p0, p1);
max = XMVector.Max(p0, p1);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
//// Axis == (0,1,0) x e0 = (e0.z, 0, -e0.x)
axis = new XMVector(e0.Z, e0.W, -e0.X, e0.Y);
p0 = XMVector3.Dot(tV0, axis);
//// p1 = XMVector3Dot( V1, Axis ); // p1 = p0;
p2 = XMVector3.Dot(tV2, axis);
min = XMVector.Min(p0, p2);
max = XMVector.Max(p0, p2);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
//// Axis == (0,1,0) x e1 = (e1.z, 0, -e1.x)
axis = new XMVector(e1.Z, e1.W, -e1.X, e1.Y);
p0 = XMVector3.Dot(tV0, axis);
p1 = XMVector3.Dot(tV1, axis);
//// p2 = XMVector3Dot( V2, Axis ); // p2 = p1;
min = XMVector.Min(p0, p1);
max = XMVector.Max(p0, p1);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
//// Axis == (0,0,1) x e2 = (e2.z, 0, -e2.x)
axis = new XMVector(e2.Z, e2.W, -e2.X, e2.Y);
p0 = XMVector3.Dot(tV0, axis);
p1 = XMVector3.Dot(tV1, axis);
//// p2 = XMVector3Dot( V2, Axis ); // p2 = p0;
min = XMVector.Min(p0, p1);
max = XMVector.Max(p0, p1);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
//// Axis == (0,0,1) x e0 = (-e0.y, e0.x, 0)
axis = new XMVector(-e0.Y, e0.X, e0.W, e0.Z);
p0 = XMVector3.Dot(tV0, axis);
//// p1 = XMVector3Dot( V1, Axis ); // p1 = p0;
p2 = XMVector3.Dot(tV2, axis);
min = XMVector.Min(p0, p2);
max = XMVector.Max(p0, p2);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
//// Axis == (0,0,1) x e1 = (-e1.y, e1.x, 0)
axis = new XMVector(-e1.Y, e1.X, e1.W, e1.Z);
p0 = XMVector3.Dot(tV0, axis);
p1 = XMVector3.Dot(tV1, axis);
//// p2 = XMVector3Dot( V2, Axis ); // p2 = p1;
min = XMVector.Min(p0, p1);
max = XMVector.Max(p0, p1);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
//// Axis == (0,0,1) x e2 = (-e2.y, e2.x, 0)
axis = new XMVector(-e2.Y, e2.X, e2.W, e2.Z);
p0 = XMVector3.Dot(tV0, axis);
p1 = XMVector3.Dot(tV1, axis);
//// p2 = XMVector3Dot( V2, Axis ); // p2 = p0;
min = XMVector.Min(p0, p1);
max = XMVector.Max(p0, p1);
radius = XMVector3.Dot(v_extents, axis.Abs());
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(min, radius));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(max, -radius));
return(XMVector4.NotEqualInt(noIntersection, XMVector.TrueInt));
}