# fakes/meadow.ludic - ground built by hand for ludic.nav's tests: n metre squares a side, flat at
# y = 0; river 1 crosses x 18..22 with a ford at z 30..34, river 2 without one, river 0 is none
function ground(n: int, river: int) -> NavGround {
  let g = new NavGround
  g.nv = (n + 1) * (n + 1)
  g.v = floats(g.nv * 3)
  for j in 0 .. n + 1 {
    for i in 0 .. n + 1 {
      let o = (j * (n + 1) + i) * 3
      g.v[o] = float(i)
      g.v[o + 2] = float(j)
    }
  }
  g.nt = n * n * 2
  g.t = new []int
  g.area = buffer(g.nt)
  for j in 0 .. n {
    for i in 0 .. n {
      let a = j * (n + 1) + i
      push(g.t, a)
      push(g.t, a + n + 1)
      push(g.t, a + 1)
      push(g.t, a + 1)
      push(g.t, a + n + 1)
      push(g.t, a + n + 2)
      var k = 1
      if river > 0 and i >= 18 and i < 22 and not (river == 1 and j >= 30 and j < 34) { k = 0 }
      g.area[(j * n + i) * 2] = k
      g.area[(j * n + i) * 2 + 1] = k
    }
  }
  return g
}

# a post r wide at (x, z), from under the ground to over a walker's head
function post_at(x: float, z: float, r: float) -> []float {
  let c = floats(5)
  c[0] = x
  c[1] = -1.0
  c[2] = z
  c[3] = r
  c[4] = 4.0
  return c
}

# a square footprint 2h across at (x, z), as a boulder's is written: n, the corners, ymin, ymax
function square_at(x: float, z: float, h: float) -> []float {
  let f = floats(11)
  f[0] = 4.0
  f[1] = x - h
  f[2] = z - h
  f[3] = x + h
  f[4] = z - h
  f[5] = x + h
  f[6] = z + h
  f[7] = x - h
  f[8] = z + h
  f[9] = -1.0
  f[10] = 3.0
  return f
}