(Improvement) Add additional calculation methods to RoomXY (#521)

CHANGELOG.md

@@ -10,6 +10,28 @@ Unreleased
   every position set to a given `u8` value
 - Implement `JsCollectionIntoValue` and `JsCollectionFromValue` for `IntershardResourceType` and
   `u32` to allow `game::resources()` return value to be used as expected
+- Add static function `RoomXY::new` to allow creating a new `RoomXY` from `RoomCoordinates`
+- Add static function `RoomXY::checked_new` to allow creating a new `RoomXY` from a (u8, u8)
+  pair, while checking the validity of the coordinates provided
+- Add function `RoomXY::towards` which returns a `RoomXY` between two `RoomXY` positions,
+  rounding towards the start position if necessary
+- Add function `RoomXY::between` which returns a `RoomXY` between two `RoomXY` positions,
+  rounding towards the target position if necessary
+- Add function `RoomXY::midpoint_between` which returns the `RoomXY` midpoint between
+  two `RoomXY` positions, rounding towards the target position if necessary
+- Add function `RoomXY::offset` which modifies a `RoomXY` in-place by a (i8, i8) offset
+- Add function `RoomXY::get_direction_to` which returns a `Direction` that is closest to
+  a given `RoomXY` position
+- Add function `RoomXY::get_range_to` which returns the Chebyshev Distance to a given
+  `RoomXY` position
+- Add function `RoomXY::in_range_to` which returns whether the Chebyshev Distance to a given
+  `RoomXY` position is less-than-or-equal-to a given distance
+- Add function `RoomXY::is_near_to` which returns whether a given `RoomXY` position is adjacent
+- Add function `RoomXY::is_equal_to` which returns whether a given `RoomXY` position is
+  the same position
+- Implement the `PartialOrd` and `Ord` traits for `RoomXY`
+- Implement the `Add<(i8, i8)>`, `Add<Direction>`, `Sub<(i8, i8)>`, `Sub<Direction>`,
+  and `Sub<RoomXY>` traits for `RoomXY`
 
 0.21.0 (2024-05-14)
 ===================

src/local/room_xy.rs

@@ -1,10 +1,14 @@
-use std::fmt;
+use std::{cmp::Ordering, fmt};
 
 use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 
 use super::room_coordinate::{OutOfBoundsError, RoomCoordinate};
 use crate::constants::{Direction, ROOM_SIZE};
 
+mod approximate_offsets;
+mod extra_math;
+mod game_math;
+
 pub(crate) const ROOM_AREA: usize = (ROOM_SIZE as usize) * (ROOM_SIZE as usize);
 
 /// Converts a [`RoomXY`] coordinate pair to a linear index appropriate for use
@@ -67,6 +71,19 @@ pub struct RoomXY {
 }
 
 impl RoomXY {
+    /// Create a new `RoomXY` from a pair of `RoomCoordinate`.
+    #[inline]
+    pub fn new(x: RoomCoordinate, y: RoomCoordinate) -> Self {
+        RoomXY { x, y }
+    }
+
+    /// Create a new `RoomXY` from a pair of `u8`, checking that they're in
+    /// the range of valid values.
+    #[inline]
+    pub fn checked_new(x: u8, y: u8) -> Result<RoomXY, OutOfBoundsError> {
+        RoomXY::try_from((x, y))
+    }
+
     /// Create a `RoomXY` from a pair of `u8`, without checking whether it's in
     /// the range of valid values.
     ///
@@ -229,6 +246,19 @@ impl RoomXY {
     }
 }
 
+impl PartialOrd for RoomXY {
+    #[inline]
+    fn partial_cmp(&self, other: &RoomXY) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for RoomXY {
+    fn cmp(&self, other: &Self) -> Ordering {
+        (self.y, self.x).cmp(&(other.y, other.x))
+    }
+}
+
 impl fmt::Display for RoomXY {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "({}, {})", self.x, self.y)

src/local/room_xy/approximate_offsets.rs

@@ -0,0 +1,236 @@
+//! Methods related to approximating in-room positions
+//! between other in-room positions.
+
+use super::RoomXY;
+
+impl RoomXY {
+    /// Calculates an approximate midpoint between this point and the target.
+    ///
+    /// In case of a tie, rounds towards this point.
+    ///
+    /// If `distance_towards_target` is bigger than the distance to the target,
+    /// the target is returned.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use screeps::RoomXY;
+    ///
+    /// // Exact distances
+    /// let start = RoomXY::checked_new(10, 10).unwrap();
+    /// let target = RoomXY::checked_new(10, 15).unwrap();
+    /// assert_eq!(
+    ///     start.towards(target, 1),
+    ///     RoomXY::checked_new(10, 11).unwrap()
+    /// );
+    /// assert_eq!(
+    ///     start.towards(target, 4),
+    ///     RoomXY::checked_new(10, 14).unwrap()
+    /// );
+    /// assert_eq!(
+    ///     start.towards(target, 10),
+    ///     RoomXY::checked_new(10, 15).unwrap()
+    /// );
+    ///
+    /// // Approximate/rounded distances
+    /// let start = RoomXY::checked_new(10, 10).unwrap();
+    /// let target_1 = RoomXY::checked_new(15, 20).unwrap();
+    /// let target_2 = RoomXY::checked_new(0, 5).unwrap();
+    /// assert_eq!(
+    ///     start.towards(target_1, 1),
+    ///     RoomXY::checked_new(10, 11).unwrap()
+    /// );
+    /// assert_eq!(
+    ///     start.towards(target_1, 9),
+    ///     RoomXY::checked_new(14, 19).unwrap()
+    /// );
+    /// assert_eq!(
+    ///     start.towards(target_2, 1),
+    ///     RoomXY::checked_new(9, 10).unwrap()
+    /// );
+    /// ```
+    pub fn towards(self, target: RoomXY, distance_towards_target: i8) -> RoomXY {
+        let (offset_x, offset_y) = target - self;
+        let total_distance = offset_x.abs().max(offset_y.abs());
+        if distance_towards_target > total_distance {
+            return target;
+        }
+
+        let new_offset_x = (offset_x * distance_towards_target) / total_distance;
+        let new_offset_y = (offset_y * distance_towards_target) / total_distance;
+
+        self + (new_offset_x, new_offset_y)
+    }
+
+    /// Calculates an approximate midpoint between this point and the target.
+    ///
+    /// In case of a tie, rounds towards the target.
+    ///
+    /// If `distance_from_target` is bigger than the distance to the target,
+    /// this position is returned.
+    ///
+    /// Note: This is essentially the same as [`RoomXY::towards`], just rounding
+    ///       towards the target instead of the starting position.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use screeps::RoomXY;
+    ///
+    /// // Exact distances
+    /// let start = RoomXY::checked_new(10, 15).unwrap();
+    /// let target = RoomXY::checked_new(10, 10).unwrap();
+    /// assert_eq!(
+    ///     start.between(target, 1),
+    ///     RoomXY::checked_new(10, 11).unwrap()
+    /// );
+    /// assert_eq!(
+    ///     start.between(target, 4),
+    ///     RoomXY::checked_new(10, 14).unwrap()
+    /// );
+    /// assert_eq!(
+    ///     start.between(target, 10),
+    ///     RoomXY::checked_new(10, 15).unwrap()
+    /// );
+    ///
+    /// // Approximate/rounded distances
+    /// let start_1 = RoomXY::checked_new(15, 20).unwrap();
+    /// let start_2 = RoomXY::checked_new(0, 5).unwrap();
+    /// let target = RoomXY::checked_new(10, 10).unwrap();
+    /// assert_eq!(
+    ///     start_1.between(target, 1),
+    ///     RoomXY::checked_new(10, 11).unwrap()
+    /// );
+    /// assert_eq!(
+    ///     start_1.between(target, 9),
+    ///     RoomXY::checked_new(14, 19).unwrap()
+    /// );
+    /// assert_eq!(
+    ///     start_2.between(target, 1),
+    ///     RoomXY::checked_new(9, 10).unwrap()
+    /// );
+    /// ```
+    pub fn between(self, target: RoomXY, distance_from_target: i8) -> RoomXY {
+        target.towards(self, distance_from_target)
+    }
+
+    /// Calculates an approximate midpoint between this point and the target.
+    ///
+    /// In case of a tie, rounds towards the target.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use screeps::RoomXY;
+    ///
+    /// // Exact distances
+    /// let start = RoomXY::checked_new(10, 10).unwrap();
+    ///
+    /// let target_1 = RoomXY::checked_new(10, 16).unwrap();
+    /// assert_eq!(
+    ///     start.midpoint_between(target_1),
+    ///     RoomXY::checked_new(10, 13).unwrap()
+    /// );
+    ///
+    /// let target_2 = RoomXY::checked_new(20, 10).unwrap();
+    /// assert_eq!(
+    ///     start.midpoint_between(target_2),
+    ///     RoomXY::checked_new(15, 10).unwrap()
+    /// );
+    ///
+    /// let target_3 = RoomXY::checked_new(12, 12).unwrap();
+    /// assert_eq!(
+    ///     start.midpoint_between(target_3),
+    ///     RoomXY::checked_new(11, 11).unwrap()
+    /// );
+    ///
+    /// let target_4 = RoomXY::checked_new(4, 4).unwrap();
+    /// assert_eq!(
+    ///     start.midpoint_between(target_4),
+    ///     RoomXY::checked_new(7, 7).unwrap()
+    /// );
+    ///
+    /// // Approximate/rounded distances
+    /// let start = RoomXY::checked_new(10, 10).unwrap();
+    ///
+    /// let target_1 = RoomXY::checked_new(10, 15).unwrap();
+    /// assert_eq!(
+    ///     start.midpoint_between(target_1),
+    ///     RoomXY::checked_new(10, 13).unwrap()
+    /// );
+    ///
+    /// let target_2 = RoomXY::checked_new(19, 10).unwrap();
+    /// assert_eq!(
+    ///     start.midpoint_between(target_2),
+    ///     RoomXY::checked_new(15, 10).unwrap()
+    /// );
+    ///
+    /// let target_3 = RoomXY::checked_new(11, 11).unwrap();
+    /// assert_eq!(
+    ///     start.midpoint_between(target_3),
+    ///     RoomXY::checked_new(11, 11).unwrap()
+    /// );
+    ///
+    /// let target_4 = RoomXY::checked_new(15, 15).unwrap();
+    /// assert_eq!(
+    ///     start.midpoint_between(target_4),
+    ///     RoomXY::checked_new(13, 13).unwrap()
+    /// );
+    /// ```
+    pub fn midpoint_between(self, target: RoomXY) -> RoomXY {
+        let (offset_x, offset_y) = self - target;
+
+        let new_offset_x = offset_x / 2;
+        let new_offset_y = offset_y / 2;
+
+        target + (new_offset_x, new_offset_y)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::RoomXY;
+
+    fn pos(x: u8, y: u8) -> RoomXY {
+        RoomXY::checked_new(x, y).unwrap()
+    }
+
+    #[test]
+    fn towards_accurate() {
+        let start = pos(10, 10);
+        assert_eq!(start.towards(pos(10, 15), 1), pos(10, 11));
+        assert_eq!(start.towards(pos(10, 15), 4), pos(10, 14));
+        assert_eq!(start.towards(pos(10, 15), 10), pos(10, 15));
+        assert_eq!(start.towards(pos(15, 15), 1), pos(11, 11));
+        assert_eq!(start.towards(pos(15, 15), 3), pos(13, 13));
+        assert_eq!(start.towards(pos(15, 20), 2), pos(11, 12));
+        assert_eq!(start.towards(pos(0, 5), 2), pos(8, 9));
+    }
+    #[test]
+    fn towards_approximate() {
+        let start = pos(10, 10);
+        assert_eq!(start.towards(pos(15, 20), 1), pos(10, 11));
+        assert_eq!(start.towards(pos(15, 20), 9), pos(14, 19));
+        assert_eq!(start.towards(pos(0, 5), 1), pos(9, 10));
+    }
+    #[test]
+    fn midpoint_accurate() {
+        let start = pos(10, 10);
+        assert_eq!(start.midpoint_between(pos(10, 16)), pos(10, 13));
+        assert_eq!(start.midpoint_between(pos(20, 10)), pos(15, 10));
+        assert_eq!(start.midpoint_between(pos(12, 12)), pos(11, 11));
+        assert_eq!(start.midpoint_between(pos(4, 4)), pos(7, 7));
+    }
+    #[test]
+    fn midpoint_approximate() {
+        let start = pos(10, 10);
+        assert_eq!(start.midpoint_between(pos(10, 15)), pos(10, 13));
+        assert_eq!(start.midpoint_between(pos(19, 10)), pos(15, 10));
+        assert_eq!(start.midpoint_between(pos(11, 11)), pos(11, 11));
+        assert_eq!(start.midpoint_between(pos(15, 15)), pos(13, 13));
+        assert_eq!(start.midpoint_between(pos(15, 25)), pos(13, 18));
+        assert_eq!(start.midpoint_between(pos(9, 10)), pos(9, 10));
+        assert_eq!(start.midpoint_between(pos(7, 10)), pos(8, 10));
+        assert_eq!(start.midpoint_between(pos(1, 3)), pos(5, 6));
+    }
+}