Merge pull request #768 from joriskleiber/snapped-int-vectors

Add `snapped` to integer vectors

Author: Bromeon

godot-core/src/builtin/vectors/vector2i.rs

@@ -44,6 +44,8 @@ impl_vector_fns!(Vector2i, glam::IVec2, i32, (x, y));
 impl_vector2x_fns!(Vector2i, i32);
 
 impl Vector2i {
+    impl_integer_vector_fns!(x, y);
+
     /// Constructs a new `Vector2i` from a [`Vector2`]. The floating point coordinates will be truncated.
     #[inline]
     pub const fn from_vector2(v: Vector2) -> Self {

godot-core/src/builtin/vectors/vector3i.rs

@@ -47,6 +47,8 @@ impl_vector_fns!(Vector3i, glam::IVec3, i32, (x, y, z));
 impl_vector3x_fns!(Vector3i, i32);
 
 impl Vector3i {
+    impl_integer_vector_fns!(x, y, z);
+
     /// Constructs a new `Vector3i` from a [`Vector3`]. The floating point coordinates will be truncated.
     #[inline]
     pub const fn from_vector3(v: Vector3) -> Self {

godot-core/src/builtin/vectors/vector4i.rs

@@ -48,6 +48,8 @@ impl_vector_fns!(Vector4i, glam::IVec4, i32, (x, y, z, w));
 impl_vector4x_fns!(Vector4i, i32);
 
 impl Vector4i {
+    impl_integer_vector_fns!(x, y, z, w);
+
     /// Constructs a new `Vector4i` from a [`Vector4`]. The floating point coordinates will be
     /// truncated.
     #[inline]

godot-core/src/builtin/vectors/vector_macros.rs

@@ -457,6 +457,60 @@ macro_rules! impl_vector_fns {
     }
 }
 
+pub(super) fn snap_one(mut value: i32, step: i32) -> i32 {
+    assert!(
+        value != i32::MIN || step != -1,
+        "snapped() called on vector component i32::MIN with step component -1"
+    );
+
+    if step != 0 {
+        // Can overflow if step / 2 + value is not in range of i32.
+        let a = (step / 2).checked_add(value).expect(
+            "snapped() overflowed, this happened because step / 2 + component is not in range of i32",
+        );
+
+        // Manually implement `a.div_floor(step)` since Rust's native method is still unstable, as of 1.79.0.
+
+        // Can overflow with a == i32::MIN and step == -1 when value == i32::MIN.
+        let mut d = a / step;
+        // Can't overflow because if a == i32::MIN and step == -1, value == -2147483647.5 which is impossible.
+        let r = a % step;
+        if (r > 0 && step < 0) || (r < 0 && step > 0) {
+            // Can't overflow because if d == i32::MIN than a == i32::MIN and step == 1 and value == -2147483648.5 which is impossible.
+            d -= 1;
+        }
+
+        value = step * d;
+    }
+
+    value
+}
+
+/// Implements functions that are present only on integer vectors.
+macro_rules! impl_integer_vector_fns {
+    (
+        // Names of the components, for example `x, y`.
+        $($comp:ident),*
+    ) => {
+        /// A new vector with each component snapped to the closest multiple of the corresponding
+        /// component in `step`.
+        ///
+        /// # Panics
+        /// On under- or overflow:
+        /// - If any component of `self` is [`i32::MIN`] while the same component on `step` is `-1`.
+        /// - If any component of `self` plus half of the same component of `step` is not in range on [`i32`].
+        pub fn snapped(self, step: Self) -> Self {
+            use crate::builtin::vectors::vector_macros::snap_one;
+
+            Self::new(
+                $(
+                    snap_one(self.$comp, step.$comp)
+                ),*
+            )
+        }
+    };
+}
+
 /// Implements functions that are present only on floating-point vectors.
 macro_rules! impl_float_vector_fns {
     (
@@ -642,7 +696,6 @@ macro_rules! impl_float_vector_fns {
 
             /// A new vector with each component snapped to the closest multiple of the corresponding
             /// component in `step`.
-            // TODO: also implement for integer vectors
             #[inline]
             pub fn snapped(self, step: Self) -> Self {
                 Self::new(

itest/rust/src/builtin_tests/geometry/vector_test/vector2i_test.rs

@@ -102,11 +102,13 @@ fn sign() {
     assert_eq!(b.sign(), b.as_inner().sign());
 }
 
-// TODO: implement snapped for integer vectors
-// #[itest]
-// fn snapped() {
-//     let a = Vector2i::new(12, 34);
-//     let b = Vector2i::new(5, -5);
-
-//     assert_eq!(a.snapped(b), a.as_inner().snapped(b));
-// }
+#[itest]
+fn snapped() {
+    let a = Vector2i::new(12, 34);
+    let b = Vector2i::new(5, -5);
+    let c = Vector2i::new(0, 0);
+    let d = Vector2i::new(3, 0);
+
+    assert_eq!(a.snapped(b), a.as_inner().snapped(b));
+    assert_eq!(c.snapped(d), c.as_inner().snapped(d));
+}

itest/rust/src/builtin_tests/geometry/vector_test/vector3i_test.rs

@@ -99,11 +99,13 @@ fn sign() {
     assert_eq!(b.sign(), b.as_inner().sign());
 }
 
-// TODO: implement snapped for integer vectors
-// #[itest]
-// fn snapped() {
-//     let a = Vector3i::new(12, 34, 56);
-//     let b = Vector3i::new(5, -5, 6);
-
-//     assert_eq!(a.snapped(b), a.as_inner().snapped(b));
-// }
+#[itest]
+fn snapped() {
+    let a = Vector3i::new(12, 34, -56);
+    let b = Vector3i::new(5, -5, 6);
+    let c = Vector3i::new(0, 3, 0);
+    let d = Vector3i::new(3, 0, 0);
+
+    assert_eq!(a.snapped(b), a.as_inner().snapped(b));
+    assert_eq!(c.snapped(d), c.as_inner().snapped(d));
+}

itest/rust/src/builtin_tests/geometry/vector_test/vector4i_test.rs

@@ -103,11 +103,13 @@ fn sign() {
     assert_eq!(b.sign(), b.as_inner().sign());
 }
 
-// TODO: implement snapped for integer vectors
-// #[itest]
-// fn snapped() {
-//     let a = Vector4i::new(12, 34, 56, 78);
-//     let b = Vector4i::new(5, -5, 6, -6);
-
-//     assert_eq!(a.snapped(b), a.as_inner().snapped(b));
-// }
+#[itest]
+fn snapped() {
+    let a = Vector4i::new(12, 34, 56, -78);
+    let b = Vector4i::new(5, -5, 6, 6);
+    let c = Vector4i::new(0, 3, 0, 0);
+    let d = Vector4i::new(3, 0, -3, 0);
+
+    assert_eq!(a.snapped(b), a.as_inner().snapped(b));
+    assert_eq!(c.snapped(d), c.as_inner().snapped(d));
+}