// Move overrides the default movement behaviour so that motion is applied to
// any associated bodies as velocity instead of directly updating the location.
func (p *part) Move(x, y, z float64) {
if p.body == nil {
p.pov.Move(x, y, z)
} else {
// apply push in the current direction.
dx, dy, dz := lin.MultSQ(x, y, z, p.dir)
p.body.Push(dx, dy, dz)
}
}
// Implements Shape.Aabb
// The axis aligned bounding box must be big enough to surround a box
// that has been transformed.
func (b *box) Aabb(t *lin.T, ab *Abox, margin float64) *Abox {
// transform the basis vectors, keeping them positive for extents.
xx, xy, xz := lin.MultSQ(1, 0, 0, t.Rot)
yx, yy, yz := lin.MultSQ(0, 1, 0, t.Rot)
zx, zy, zz := lin.MultSQ(0, 0, 1, t.Rot)
xx, xy, xz = math.Abs(xx), math.Abs(xy), math.Abs(xz)
yx, yy, yz = math.Abs(yx), math.Abs(yy), math.Abs(yz)
zx, zy, zz = math.Abs(zx), math.Abs(zy), math.Abs(zz)
// Dot the half-extents, plus margin, with the transformed basis vectors.
// to get the furthest extent in each direction.
hmx, hmy, hmz := b.Hx+margin, b.Hy+margin, b.Hz+margin
ex := hmx*xx + hmy*xy + hmz*xz
ey := hmx*yx + hmy*yy + hmz*yz
ez := hmx*zx + hmy*zy + hmz*zz
ab.Sx, ab.Sy, ab.Sz = t.Loc.X-ex, t.Loc.Y-ey, t.Loc.Z-ez
ab.Lx, ab.Ly, ab.Lz = t.Loc.X+ex, t.Loc.Y+ey, t.Loc.Z+ez
return ab
}
// Move increments the current position with respect to the current
// orientation, i.e. adds the distance travelled in the current direction
// to the current location.
func (p *pov) Move(x, y, z float64) {
dx, dy, dz := lin.MultSQ(x, y, z, p.dir)
p.loc.X += dx
p.loc.Y += dy
p.loc.Z += dz
}