# update.ludic - a frame of the body: the stick in the camera's frame, the step, the gait, the camera
export function char_update(character_st: mut CharacterState, ix0: float, iz0: float, run0: bool, jump0: bool, dyaw: float, dpitch: float, dt: float) -> void {
  var run = run0 and character_st.chr_can_run
  var ix = ix0
  var iz = iz0
  var jump = jump0
  character_st.chr_step = 0.0
  character_st.chr_time = character_st.chr_time + dt
  character_st.chr_water = CharacterGround.water(character_st.chr_x, character_st.chr_z)
  chr_sit_tick(character_st, dt)
  if CharacterBody.riding() {
    chr_ride_update(character_st, ix, iz, run, dyaw, dpitch, dt)
    return
  }
  if CharacterBody.sneaking() { run = false }
  # sitting: any step stands up, and nothing else moves
  if character_st.chr_sit and (Math.abs(ix) > 0.3 or Math.abs(iz) > 0.3 or jump) { character_st.chr_sit = false }
  if character_st.chr_sit {
    ix = 0.0
    iz = 0.0
    jump = false
  }
  # the stick in the camera's frame: forward on the ground is (-sin yaw, -cos yaw)
  let cy = Math.cos(character_st.chr_cam_yaw)
  let sy = Math.sin(character_st.chr_cam_yaw)
  var dx = -sy * iz + cy * ix
  var dz = -cy * iz - sy * ix
  var mag = Math.sqrt(dx * dx + dz * dz)
  if mag > 1.0 {
    dx = dx / mag
    dz = dz / mag
    mag = 1.0
  }
  chr_steer(character_st, dx, dz, mag, run, dt)
  # seated, the seat holds the body (chr_sit_tick): handed to the walker too, it was pushed off a
  # log or a bench and pulled back each frame, and shook
  var dist = 0.0
  if not character_st.chr_sit or character_st.chr_swim { dist = chr_travel(character_st, dx, dz, -Math.sin(character_st.chr_yaw), -Math.cos(character_st.chr_yaw), jump, dt) }
  chr_gait(character_st, dist, dyaw, dpitch, dt)
  char_camera(character_st, dt)
}

# something else carries the body (CharacterBody.ride moves it with char_ride_at); the orbit
# drifts behind whatever it is on
function chr_ride_update(character_st: mut CharacterState, ix: float, iz: float, run: bool, dyaw: float, dpitch: float, dt: float) -> void {
  CharacterBody.ride(ix, iz, run, dt)
  chr_look(character_st, dyaw, dpitch)
  if dyaw == 0.0 and not CharacterInput.look_always() { character_st.chr_cam_yaw = character_st.chr_cam_yaw + char_wrap(character_st.chr_yaw - character_st.chr_cam_yaw) * Math.min(1.0, 1.5 * dt) }
  char_camera(character_st, dt)
}

# a frame from the input port: the game's devices, read once, stepping the body
export function char_tick(character_st: mut CharacterState, dt: float) -> void {
  var ix = 0.0
  var iz = 0.0
  var run = false
  var jump = false
  var dyaw = 0.0
  var dpitch = 0.0
  if character_st.chr_holds == 0 {
    ix = CharacterInput.move_x()
    iz = CharacterInput.move_z()
    run = CharacterInput.run()
    jump = CharacterInput.jump()
    dyaw = CharacterInput.look_yaw()
    dpitch = CharacterInput.look_pitch()
    let wheel = CharacterInput.zoom()
    if wheel != 0.0 { character_st.chr_cam_dist = Math.clamp(character_st.chr_cam_dist - wheel * 0.35, 1.8, 9.0) }
  }
  char_update(character_st, ix, iz, run, jump, dyaw, dpitch, dt)
}