public unsafe DisplacementVector GetBilinearSample(float x, float y)
{
int x0, y0;
if (x >= width - 1)
{
x = width - 1;
x0 = width - 2;
}
else
{
if (x < 0)
{
x = 0;
}
x0 = (int)x;
}
if (y >= height - 1)
{
y = height - 1;
y0 = height - 2;
}
else
{
if (y < 0)
{
y = 0;
}
y0 = (int)y;
}
float factorX = x - x0;
DisplacementVector *
tl = GetPointAddressUnchecked(x0, y0),
bl = tl + width;
DisplacementVector
t = DisplacementVector.Lerp(*tl, *(tl + 1), factorX),
b = DisplacementVector.Lerp(*bl, *(bl + 1), factorX);
return(DisplacementVector.Lerp(t, b, y - y0));
}
public unsafe DisplacementMesh Resize(Size size)
{
DisplacementMesh ret = new DisplacementMesh(size);
float xfactor = (float)width / size.Width;
float yfactor = (float)height / size.Height;
for (int y = 0; y < size.Height; ++y)
{
DisplacementVector *ptr = ret.GetPointAddressUnchecked(0, y);
float srcy = y * yfactor;;
for (int x = 0; x < size.Width; ++x)
{
float srcx = x * xfactor;
DisplacementVector v = GetBilinearSample(srcx, srcy);
ptr->X = v.X / xfactor;
ptr->Y = v.Y / yfactor;
++ptr;
}
}
return(ret);
}
public static DisplacementVector Lerp(DisplacementVector lhs, DisplacementVector rhs, float factor)
{
return(new DisplacementVector(
lhs.X * (1 - factor) + rhs.X * factor,
lhs.Y * (1 - factor) + rhs.Y * factor));
}
public Rectangle SetPoint(int pi, int pj, float nx, float ny)
{
int istart = pi - 1,
iend = pi + 2,
jstart = pj - 1,
jend = pj + 2;
if (istart < 0)
{
istart = 0;
}
else if (iend > handlesx)
{
iend = handlesx;
}
if (jstart < 0)
{
jstart = 0;
}
else if (jend > handlesy)
{
jend = handlesy;
}
int l = mesh.Width,
t = mesh.Height,
r = 0,
b = 0;
for (int j = jstart; j < jend; ++j)
{
for (int i = istart; i < iend; ++i)
{
float bx = i + points[i, j].X;
float by = j + points[i, j].Y;
int x = (int)(bx * xspacing);
int y = (int)(by * yspacing);
if (x < l)
{
l = x;
}
if (x > r)
{
r = x;
}
if (y < t)
{
t = y;
}
if (y > b)
{
b = y;
}
if (i > pi && nx + pi > bx)
{
nx = bx - pi - delx;
}
else if (i < pi && nx + pi < bx)
{
nx = bx - pi + delx;
}
if (j > pj && ny + pj > by)
{
ny = by - pj - dely;
}
else if (j < pj && ny + pj < by)
{
ny = by - pj + dely;
}
}
}
if (l < 0)
{
l = 0;
}
if (r > mesh.Width)
{
r = mesh.Width;
}
if (t < 0)
{
t = 0;
}
if (b > mesh.Height)
{
b = mesh.Height;
}
if (nx + pi < 0)
{
nx = -pi;
}
else if (nx + pi > width)
{
nx = width - pi;
}
if (ny + pj < 0)
{
ny = -pj;
}
else if (ny + pj > height)
{
ny = height - pj;
}
points[pi, pj] = new DisplacementVector(nx, ny);
QueuePointUpdate(pi, pj);
return(Rectangle.FromLTRB(l, t, r, b));
}