// Handle movement assuming there is a physics body associated with the camera.
// This attempts to smooth out movement by adding a higher initial velocity push
// and then capping movement once max accelleration is reached.
func (c *cam) move(bod vu.Pov, x, y, z float64, dir *lin.Q) {
if body := bod.Body(); body != nil {
boost := 40.0 // kick into high gear from stop.
maxAccel := 10.0 // limit accelleration.
sx, _, sz := body.Speed()
if x != 0 {
switch {
case sx == 0.0:
// apply push in the current direction.
dx, dy, dz := lin.MultSQ(x*boost, 0, 0, dir)
body.Push(dx, dy, dz)
case math.Abs(sx) < maxAccel && math.Abs(sz) < maxAccel:
dx, dy, dz := lin.MultSQ(x, 0, 0, dir)
body.Push(dx, dy, dz)
}
}
if z != 0 {
switch {
case sz == 0.0:
dx, dy, dz := lin.MultSQ(0, 0, z*boost, dir)
body.Push(dx, dy, dz)
case math.Abs(sx) < maxAccel && math.Abs(sz) < maxAccel:
dx, dy, dz := lin.MultSQ(0, 0, z, dir)
body.Push(dx, dy, dz)
}
}
} else {
bod.Move(x, y, z, dir)
}
}
// Culler implmentation.
// Project the part location back along the lookat vector.
func (fc *frontCull) Cull(cam Camera, px, py, pz float64) bool {
fudgeFactor := float64(0.8) // don't move all the way up.
cx, cy, cz := lin.MultSQ(0, 0, -fc.radius*fudgeFactor, cam.Lookat())
px, py, pz = px-cx, py-cy, pz-cz // move part location back.
toc := cam.Distance(px, py, pz) // cull if outside radius.
return toc > fc.rr
}
// Move relative to the given orientation.
// Use Look() to fly. Use Yaw() to run along XZ.
func (c *camera) Move(x, y, z float64, q *lin.Q) {
dx, dy, dz := lin.MultSQ(x, y, z, q)
c.at.Loc.X += dx
c.at.Loc.Y += dy
c.at.Loc.Z += dz
c.updateTransform()
}
// 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
// assign the final Aabb values.
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 directly affects the location by the given translation amounts
// along the given direction. Physics bodies should use Body.Push which
// affects velocity.
func (p *pov) Move(x, y, z float64, dir *lin.Q) {
dx, dy, dz := lin.MultSQ(x, y, z, dir)
p.at.Loc.X += dx
p.at.Loc.Y += dy
p.at.Loc.Z += dz
}