ludic/packages/ludic.wildlife/habitat.ludic

# habitat.ludic - the right kind of ground for a species, asked of the port's ground, water, slope
# and forest; and a spot of it at a distance from a point, off the package's dice

function wl_wet(x: float, z: float, depth: float) -> bool {
  return WildlifeWorld.ground(x, z) < WildlifeWorld.water(x, z) - depth
}

export function wildlife_habitat_ok(hab: int, x: float, z: float) -> bool {
  let h = WildlifeWorld.ground(x, z)
  let w = WildlifeWorld.water(x, z)
  if h < w + 0.8 { return false }
  let s = WildlifeWorld.slope(x, z)
  if hab == WILD_MEADOW { return s < 0.28 and not WildlifeWorld.forest(x, z) }
  if hab == WILD_FOREST { return s < 0.5 and WildlifeWorld.forest(x, z) }
  if hab == WILD_SHORE { return h < w + 4.0 and s < 0.4 }
  return s > 0.25 or h > 80.0
}

# a spot of `hab` d0..d1 metres from (x0, z0); where it is, is wildlife_spot_x / _z
export function wildlife_find_spot(wildlife_st: mut WildlifeState, hab: int, x0: float, z0: float, d0: float, d1: float) -> bool {
  for t in 0 .. 60 {
    let ang = wl_rnd(wildlife_st) * WL_TAU
    let d = d0 + wl_rnd(wildlife_st) * (d1 - d0)
    let x = x0 + Math.cos(ang) * d
    let z = z0 + Math.sin(ang) * d
    if wildlife_habitat_ok(hab, x, z) {
      wildlife_st.wl_px = x
      wildlife_st.wl_pz = z
      return true
    }
  }
  return false
}

export function wildlife_spot_x(wildlife_st: WildlifeState) -> float { return wildlife_st.wl_px }
export function wildlife_spot_z(wildlife_st: WildlifeState) -> float { return wildlife_st.wl_pz }