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use crate::local::{position::WorldPositionOutOfBoundsError, VALID_WORLD_POSITIONS};
use super::{Position, HALF_WORLD_SIZE};
impl Position {
/// Returns this position's horizontal "world coordinate".
///
/// The value is equal to `50 * room_x + x`, where `room_x` is defined as
/// `room_x = -xx - 1` for `Wxx` rooms and as `room_x = xx` for `Exx` rooms.
#[inline]
pub fn world_x(self) -> i32 {
self.room_x() * 50 + (u8::from(self.x()) as i32)
}
/// Returns this position's vertical "world coordinate".
///
/// The value is equal to `50 * room_y + y`, where `room_y` is defined as
/// `room_y = -yy - 1` for `Nyy` rooms and as `room_y = yy` for `Syy` rooms.
#[inline]
pub fn world_y(self) -> i32 {
self.room_y() * 50 + (u8::from(self.y()) as i32)
}
/// Returns this position's "world coordinates".
///
/// The first value is equal to `50 * room_x + x`, where `room_x` is defined
/// as `room_x = -xx - 1` for `Wxx` rooms and as `room_x = xx` for `Exx`
/// rooms.
///
/// The second value is equal to `50 * room_y + y`, where `room_y` is
/// defined as `room_y = -yy - 1` for `Nyy` rooms and as `room_y = yy`
/// for `Syy` rooms.
///
/// See also [`Position::world_x`] and
/// [`Position::world_y`].
#[inline]
pub fn world_coords(self) -> (i32, i32) {
(self.world_x(), self.world_y())
}
/// Creates a room position from world coords.
///
/// # Panics
///
/// Panics if either x or y is out of the range `-128 * 50 .. +128 * 50`.
///
/// For a checked variant of this function, see
/// [`Position::checked_from_world_coords`].
///
/// See [`Position::world_coords`].
#[inline]
#[track_caller]
pub fn from_world_coords(x: i32, y: i32) -> Self {
Self::checked_from_world_coords(x, y).unwrap()
}
/// Creates a room position from world coords if they are within the range
/// `-128 * 50 .. +128 * 50`. Otherwise returns `None`.
///
/// For a panicing variant of this function, see
/// [`Position::from_world_coords`].
///
/// See [`Position::world_coords`].
#[inline]
pub fn checked_from_world_coords(
x: i32,
y: i32,
) -> Result<Self, WorldPositionOutOfBoundsError> {
if VALID_WORLD_POSITIONS.contains(&x) && VALID_WORLD_POSITIONS.contains(&y) {
// We do the `HALF_WORLD_SIZE` transition here first so that the division and
// modulo operations work correctly.
let pos_x = (x + HALF_WORLD_SIZE * 50) as u32;
let pos_y = (y + HALF_WORLD_SIZE * 50) as u32;
let room_x = pos_x / 50;
let room_y = pos_y / 50;
let x = (pos_x % 50) as u8;
let y = (pos_y % 50) as u8;
Ok(Self::from_coords_and_world_coords_adjusted(
x, y, room_x, room_y,
))
} else {
Err(WorldPositionOutOfBoundsError(x, y))
}
}
}
#[cfg(test)]
mod test {
use super::Position;
use crate::{
local::{position::WorldPositionOutOfBoundsError, RoomCoordinate},
ROOM_SIZE,
};
use core::ops::Range;
const TEST_ROOM_NAMES: &[&str] = &[
"E1N1", "E20N0", "W0N0", "E0N0", "W0S0", "E0S0", "W0N0", "E0N0", "W0S0", "E0S0", "W50S20",
"W127S127", "W127N127", "E127S127", "E127N127",
];
fn gen_test_coords() -> [RoomCoordinate; 4] {
unsafe {
[
RoomCoordinate::unchecked_new(0),
RoomCoordinate::unchecked_new(21),
RoomCoordinate::unchecked_new(44),
RoomCoordinate::unchecked_new(49),
]
}
}
#[test]
fn world_coords_round_trip() {
for room_name in TEST_ROOM_NAMES {
for x in gen_test_coords().iter().cloned() {
for y in gen_test_coords().iter().cloned() {
let original_pos = Position::new(x, y, room_name.parse().unwrap());
let (wx, wy) = original_pos.world_coords();
let new = Position::from_world_coords(wx, wy);
assert_eq!(original_pos, new);
}
}
}
}
#[test]
fn checked_world_coords() {
// this tests:
// - the 16 rooms around the center of the world
// - the 16 rooms around each corner of the max world size (12 of them are out
// of bounds)
const ROOM_RANGE: Range<i32> = -((ROOM_SIZE as i32) * 2)..((ROOM_SIZE as i32) * 2);
for x in ROOM_RANGE {
for y in ROOM_RANGE {
let room_x = x.div_euclid(50);
let room_y = y.div_euclid(50);
let pos_x = x.rem_euclid(50) as u8;
let pos_y = y.rem_euclid(50) as u8;
let new_pos = Position::checked_from_world_coords(x, y).unwrap();
assert_eq!(room_x, new_pos.room_x());
assert_eq!(room_y, new_pos.room_y());
assert_eq!(pos_x, new_pos.x().u8());
assert_eq!(pos_y, new_pos.y().u8());
}
}
const CORNERS: [(i32, i32); 4] =
[(-6400, 6399), (6399, 6399), (-6400, -6400), (6399, 6400)];
for (corner_x, corner_y) in CORNERS {
for x in ROOM_RANGE {
for y in ROOM_RANGE {
let x = corner_x + x;
let y = corner_y + y;
if !(-6400..=6399).contains(&x) || !(-6400..=6399).contains(&y) {
assert_eq!(
Err(WorldPositionOutOfBoundsError(x, y)),
Position::checked_from_world_coords(x, y)
);
} else {
let room_x = x.div_euclid(50);
let room_y = y.div_euclid(50);
let pos_x = x.rem_euclid(50) as u8;
let pos_y = y.rem_euclid(50) as u8;
let new_pos = Position::checked_from_world_coords(x, y).unwrap();
assert_eq!(room_x, new_pos.room_x());
assert_eq!(room_y, new_pos.room_y());
assert_eq!(pos_x, new_pos.x().u8());
assert_eq!(pos_y, new_pos.y().u8());
}
}
}
}
}
#[test]
#[should_panic(expected = "WorldPositionOutOfBoundsError(6400, 6400)")]
fn oob_world_coords_panic() {
// note: world coords are -6400..6400 (not including the end)
let _val = Position::from_world_coords(6400, 6400);
}
#[test]
#[should_panic(expected = "WorldPositionOutOfBoundsError(6400, 6399)")]
fn oob_coords_add() {
let pos = Position::from_world_coords(6395, 6399);
let _new_pos = pos + (5, 0);
}
// don't run this test if debug assertions are enabled, it won't complete
#[cfg(not(debug_assertions))]
#[test]
fn exhaustive_checked_world_coords() {
use crate::local::VALID_WORLD_POSITIONS;
// Test that the entire input space returns `Some` or `None` as expected.
// If this test completes in release mode, it means that the compiler is able to
// prove enough to optimize it away. If the test stops being instant,
// something went wrong with the implementation or the compiler (probably the
// implementation).
for x in i32::MIN..=i32::MAX {
for y in i32::MIN..=i32::MAX {
if VALID_WORLD_POSITIONS.contains(&x) && VALID_WORLD_POSITIONS.contains(&y) {
assert!(matches!(Position::checked_from_world_coords(x, y), Ok(_)));
} else {
assert_eq!(
Err(WorldPositionOutOfBoundsError(x, y)),
Position::checked_from_world_coords(x, y)
);
}
}
}
}
}