public RayDifferential this[RayDifferential r]
{
get
{
RayDifferential tr = new RayDifferential();
if (!actuallyAnimated || r.Time <= startTime)
tr = (startTransform)[r];
else if (r.Time >= endTime)
tr = (endTransform)[r];
else
{
Transform t = new Transform();
Interpolate(r.Time, t);
tr = t[r];
}
tr.Time = r.Time;
return tr;
}
}
public void ComputeDifferentials(RayDifferential ray)
{
if (ray.HasDifferentials)
{
float d = -Vector.Dot((Vector)nn, new Vector(p.X, p.Y, p.Z));
Vector rxv = new Vector(ray.RXOrigin.X, ray.RXOrigin.Y, ray.RXOrigin.Z);
float tx = -(Vector.Dot((Vector)nn, rxv) + d) / Vector.Dot((Vector)nn, ray.RXDirection);
if (float.IsNaN(tx))
{
dudx = dvdx = 0.0f;
dudy = dvdy = 0.0f;
dpdx = dpdy = new Vector(0, 0, 0);
goto end;
}
Point px = ray.RXOrigin + tx * ray.RXDirection;
Vector ryv = new Vector(ray.RYOrigin.X, ray.RYOrigin.Y, ray.RYOrigin.Z);
float ty = -(Vector.Dot((Vector)nn, ryv) + d) / Vector.Dot((Vector)nn, ray.RYDirection);
if (float.IsNaN(ty))
{
dudx = dvdx = 0.0f;
dudy = dvdy = 0.0f;
dpdx = dpdy = new Vector(0, 0, 0);
goto end;
}
Point py = ray.RYOrigin + ty * ray.RYDirection;
dpdx = px - p;
dpdy = py - p;
float[][] A = new float[2][];
float[] Bx = new float[2];
float[] By = new float[2];
int[] axes = new int[2];
if (MathHelper.Abs(nn.X) > MathHelper.Abs(nn.Y) && MathHelper.Abs(nn.X) > MathHelper.Abs(nn.Z))
{
axes[0] = 1; axes[1] = 2;
}
else if (MathHelper.Abs(nn.Y) > MathHelper.Abs(nn.Z))
{
axes[0] = 0; axes[1] = 2;
}
else
{
axes[0] = 0; axes[1] = 1;
}
A[0][0] = dpdu[axes[0]];
A[0][1] = dpdv[axes[0]];
A[1][0] = dpdu[axes[1]];
A[1][1] = dpdv[axes[1]];
Bx[0] = px[axes[0]] - p[axes[0]];
Bx[1] = px[axes[1]] - p[axes[1]];
By[0] = py[axes[0]] - p[axes[0]];
By[1] = py[axes[1]] - p[axes[1]];
float a = 0, b = 0, c = 0, f = 0;
if (!Transform.SolveLinearSystem2x2(A, Bx, ref a, ref b))
{
dudx = 0.0f;
dvdx = 0.0f;
}
else
{
dudx = a;
dvdx = b;
}
if (!Transform.SolveLinearSystem2x2(A, By, ref c, ref f))
{
dudy = 0.0f; dvdy = 0.0f;
}
else
{
dudy = c;
dvdy = f;
}
end:
float j = 0;
}
else
{
dudx = dvdx = 0.0f;
dudy = dvdy = 0.0f;
dpdx = dpdy = new Vector(0, 0, 0);
}
}
public RayDifferential this[RayDifferential ray]
{
get
{
RayDifferential ret = (RayDifferential)this[new Ray(ray)];
ret.HasDifferentials = ray.HasDifferentials;
ret.RXOrigin = this[ray.RXOrigin];
ret.RYOrigin = this[ray.RYOrigin];
ret.RXDirection = this[ray.RXDirection];
ret.RYDirection = this[ray.RYDirection];
return ret;
}
}