# ports.ludic - what a photograph asks the game: where the lens is and what it can see, the light,
# and the rules of the market. Unbound, the lens sits at the origin looking down -z with nothing in
# the way at noon under a clear sky, every point projects to the middle of the frame, and a
# subject's first frame is worth 12 and a legend 120.
export port PhotoLens {
  x: fn() -> float = fn pht__zero                    # the camera's position
  y: fn() -> float = fn pht__zero
  z: fn() -> float = fn pht__zero
  fx: fn() -> float = fn pht__zero                   # where it points (unit)
  fy: fn() -> float = fn pht__zero
  fz: fn() -> float = fn pht__back
  fov: fn() -> float = fn pht__fov                   # vertical, radians
  project: fn(float, float, float) -> bool = fn pht__centred   # into the picture; sx / sy say where
  sx: fn() -> float = fn pht__half                   # 0..1 across
  sy: fn() -> float = fn pht__half                   # 0..1 down
  visible: fn(float, float, float, float) -> bool = fn pht__seen   # a sphere inside the frustum
  clear: fn(float, float, float, float, float, float) -> bool = fn pht__clear   # nothing between two points
  range: fn() -> float = fn pht__range               # how far the lens reaches, m
  steady: fn() -> bool = fn pht__no                  # on a tripod
}

export port PhotoLight {
  hour: fn() -> float = fn pht__noon
  night: fn() -> bool = fn pht__no
  moon: fn() -> float = fn pht__zero                 # 0..1 lit
  dim: fn() -> int = fn pht__none                    # what the weather takes off (a storm 4)
  bonus: fn() -> int = fn pht__none                  # what it adds (the light after a front)
  sun_x: fn() -> float = fn pht__zero                # toward the sun
  sun_z: fn() -> float = fn pht__zero
}

export port PhotoRules {
  behaviour: fn() -> bool = fn pht__no               # size counts half and the moment double
  subject_value: fn(int) -> int = fn pht__twelve     # a subject's first frame, before the grade
  legend_value: fn(int) -> int = fn pht__legend
  mult: fn() -> float = fn pht__one                  # the lens's worth, times
}

function pht__zero() -> float { return 0.0 }
function pht__back() -> float { return -1.0 }
function pht__fov() -> float { return 1.0 }
function pht__centred(x: float, y: float, z: float) -> bool { return true }
function pht__half() -> float { return 0.5 }
function pht__seen(x: float, y: float, z: float, r: float) -> bool { return true }
function pht__clear(ax: float, ay: float, az: float, bx: float, by: float, bz: float) -> bool { return true }
function pht__range() -> float { return 100.0 }
function pht__no() -> bool { return false }
function pht__noon() -> float { return 12.0 }
function pht__none() -> int { return 0 }
function pht__twelve(sp: int) -> int { return 12 }
function pht__legend(sp: int) -> int { return 120 }
function pht__one() -> float { return 1.0 }