Merge #124

124: Implement the matrix types r=Bromeon a=sayaks

Implement the four matrix types godot has: `Basis`, `Transform2D`, `Transform3D`, `Projection`.

`Transform2D` in godot consists of an array of 3 `Vector2`s, where the first two are the basis.
This means godot has some methods named `Transform2D::basis_<something>()`. I
decided to instead make a struct `Basis2D`. so now any method like the above would be
called `trans.basis.<something>()` instead.

`Projection` has a lot of intricate math for many of its functions so it is largely
a wrapper around `InnerProjection`, except for some methods that were
easy to reimplement.

Depends on #128 

Co-authored-by: Lili Zoey <[email protected]>

Author: bors[bot]

godot-core/src/builtin/basis.rs

@@ -6,6 +6,8 @@
 
 use std::f32::consts::TAU;
 
+use super::Vector2;
+
 pub const CMP_EPSILON: f32 = 0.00001;
 
 pub fn lerp(a: f32, b: f32, t: f32) -> f32 {
@@ -23,6 +25,18 @@ pub fn is_equal_approx(a: f32, b: f32) -> bool {
     (a - b).abs() < tolerance
 }
 
+/// Check if two angles are approximately equal, by comparing the distance
+/// between the points on the unit circle with 0 using [`is_equal_approx`].
+pub fn is_angle_equal_approx(a: f32, b: f32) -> bool {
+    let (x1, y1) = a.sin_cos();
+    let (x2, y2) = b.sin_cos();
+
+    is_equal_approx(
+        Vector2::distance_to(Vector2::new(x1, y1), Vector2::new(x2, y2)),
+        0.0,
+    )
+}
+
 pub fn is_zero_approx(s: f32) -> bool {
     s.abs() < CMP_EPSILON
 }
@@ -190,6 +204,15 @@ mod test {
         assert_ne_approx!(1.0, 2.0, is_equal_approx, "Message {}", "formatted");
     }
 
+    #[test]
+    fn angle_equal_approx() {
+        assert_eq_approx!(1.0, 1.000001, is_angle_equal_approx);
+        assert_eq_approx!(0.0, TAU, is_angle_equal_approx);
+        assert_eq_approx!(PI, -PI, is_angle_equal_approx);
+        assert_eq_approx!(4.45783, -(TAU - 4.45783), is_angle_equal_approx);
+        assert_eq_approx!(31.0 * PI, -13.0 * PI, is_angle_equal_approx);
+    }
+
     #[test]
     #[should_panic(expected = "I am inside format")]
     fn eq_approx_fail_with_message() {
@@ -198,22 +221,17 @@ mod test {
 
     #[test]
     fn lerp_angle_test() {
-        assert_eq_approx!(lerp_angle(0.0, PI, 0.5), -FRAC_PI_2, is_equal_approx);
+        assert_eq_approx!(lerp_angle(0.0, PI, 0.5), -FRAC_PI_2, is_angle_equal_approx);
         assert_eq_approx!(
             lerp_angle(0.0, PI + 3.0 * TAU, 0.5),
             FRAC_PI_2,
-            is_equal_approx
+            is_angle_equal_approx
         );
         let angle = PI * 2.0 / 3.0;
         assert_eq_approx!(
-            lerp_angle(-5.0 * TAU, angle + 3.0 * TAU, 0.5).sin(),
-            (angle / 2.0).sin(),
-            is_equal_approx
-        );
-        assert_eq_approx!(
-            lerp_angle(-5.0 * TAU, angle + 3.0 * TAU, 0.5).cos(),
-            (angle / 2.0).cos(),
-            is_equal_approx
+            lerp_angle(-5.0 * TAU, angle + 3.0 * TAU, 0.5),
+            (angle / 2.0),
+            is_angle_equal_approx
         );
     }
 }

godot-core/src/builtin/math.rs

@@ -36,15 +36,19 @@
 pub use crate::{array, dict, varray};
 
 pub use array_inner::{Array, TypedArray};
+pub use basis::*;
 pub use color::*;
 pub use dictionary_inner::Dictionary;
 pub use math::*;
 pub use node_path::*;
 pub use others::*;
 pub use packed_array::*;
+pub use projection::*;
 pub use quaternion::*;
 pub use string::*;
 pub use string_name::*;
+pub use transform2d::*;
+pub use transform3d::*;
 pub use variant::*;
 pub use vector2::*;
 pub use vector2i::*;
@@ -79,15 +83,19 @@ mod array_inner;
 #[path = "dictionary.rs"]
 mod dictionary_inner;
 
+mod basis;
 mod color;
 mod glam_helpers;
 mod math;
 mod node_path;
 mod others;
 mod packed_array;
+mod projection;
 mod quaternion;
 mod string;
 mod string_name;
+mod transform2d;
+mod transform3d;
 mod variant;
 mod vector2;
 mod vector2i;

godot-core/src/builtin/mod.rs

@@ -17,10 +17,6 @@ impl_builtin_stub!(Rect2, OpaqueRect2);
 impl_builtin_stub!(Rect2i, OpaqueRect2i);
 impl_builtin_stub!(Plane, OpaquePlane);
 impl_builtin_stub!(Aabb, OpaqueAabb);
-impl_builtin_stub!(Basis, OpaqueBasis);
-impl_builtin_stub!(Transform2D, OpaqueTransform2D);
-impl_builtin_stub!(Transform3D, OpaqueTransform3D);
-impl_builtin_stub!(Projection, OpaqueProjection);
 impl_builtin_stub!(Rid, OpaqueRid);
 impl_builtin_stub!(Callable, OpaqueCallable);
 impl_builtin_stub!(Signal, OpaqueSignal);