From 4cc9a649fcd039a0ed415581049929b4f3310003 Mon Sep 17 00:00:00 2001
From: Ian Chamberlain <ian.h.chamberlain@gmail.com>
Date: Mon, 16 Oct 2023 00:28:11 -0400
Subject: [PATCH] More fixes for debug print + matrix equality

---
 citro3d/src/math/matrix.rs     | 27 +++++++++++++++++----------
 citro3d/src/math/ops.rs        |  2 +-
 citro3d/src/math/projection.rs |  9 +++++----
 3 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/citro3d/src/math/matrix.rs b/citro3d/src/math/matrix.rs
index f863784..79faabb 100644
--- a/citro3d/src/math/matrix.rs
+++ b/citro3d/src/math/matrix.rs
@@ -38,25 +38,32 @@ mod private {
         pub(crate) fn as_mut(&mut self) -> *mut citro3d_sys::C3D_Mtx {
             &mut self.0
         }
+
+        /// Trim the matrix down to only the rows and columns we care about,
+        /// since the inner representation is always 4x4.
+        pub(crate) fn as_rows(&self) -> [[f32; N]; M] {
+            let rows = unsafe { self.0.r }.map(|row| -> [f32; N] {
+                // Rows are stored in WZYX order, so we slice from back to front.
+                // UNWRAP: N ≤ 4, so slicing to a smaller array should always work
+                unsafe { row.c[(4 - N)..].try_into() }.unwrap()
+            });
+
+            // UNWRAP: M ≤ 4, so slicing to a smaller array should always work
+            rows[..M].try_into().unwrap()
+        }
     }
 
     impl<const M: usize, const N: usize> fmt::Debug for Matrix<M, N> {
         fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-            let rows = unsafe { self.0.r }.map(|row| {
-                // UNWRAP: N ≤ 4, so slicing to a smaller array should always work
-                let mut row: [f32; N] = unsafe { row.c[..N].try_into() }.unwrap();
+            let inner = self.as_rows().map(|mut row| {
                 // Rows are stored in WZYX order which is opposite of how most people
-                // probably expect, so we reverse each row in-place as well.
+                // probably expect, so reverse each row in-place for debug printing
                 row.reverse();
                 row
             });
 
-            // UNWRAP: M ≤ 4, so slicing to a smaller array should always work
-            let inner: [_; M] = rows[..M].try_into().unwrap();
-
-            f.debug_tuple(std::any::type_name::<Self>())
-                .field(&inner)
-                .finish()
+            let type_name = std::any::type_name::<Self>().split("::").last().unwrap();
+            f.debug_tuple(type_name).field(&inner).finish()
         }
     }
 }
diff --git a/citro3d/src/math/ops.rs b/citro3d/src/math/ops.rs
index e8c648a..8204ca4 100644
--- a/citro3d/src/math/ops.rs
+++ b/citro3d/src/math/ops.rs
@@ -157,7 +157,7 @@ impl Mul<FVec3> for &Matrix<4, 3> {
 
 impl<Rhs: Borrow<Self>, const M: usize, const N: usize> PartialEq<Rhs> for Matrix<M, N> {
     fn eq(&self, other: &Rhs) -> bool {
-        unsafe { (*self.as_raw()).m == (*other.borrow().as_raw()).m }
+        self.as_rows() == other.borrow().as_rows()
     }
 }
 
diff --git a/citro3d/src/math/projection.rs b/citro3d/src/math/projection.rs
index 278a776..46313b9 100644
--- a/citro3d/src/math/projection.rs
+++ b/citro3d/src/math/projection.rs
@@ -73,10 +73,11 @@ impl Projection<Perspective> {
     ///     far: 100.0,
     /// };
     ///
-    /// let bottom: Matrix =
+    /// let bottom: Matrix4 =
     ///     Projection::perspective(PI / 4.0, AspectRatio::BottomScreen, clip_planes).into();
     ///
-    /// let top: Matrix = Projection::perspective(PI / 4.0, AspectRatio::TopScreen, clip_planes).into();
+    /// let top: Matrix4 =
+    ///     Projection::perspective(PI / 4.0, AspectRatio::TopScreen, clip_planes).into();
     /// ```
     #[doc(alias = "Mtx_Persp")]
     #[doc(alias = "Mtx_PerspTilt")]
@@ -204,9 +205,9 @@ impl Projection<Orthographic> {
     ///
     /// ```
     /// # let _runner = test_runner::GdbRunner::default();
-    /// # use citro3d::math::{Projection, ClipPlanes, Matrix};
+    /// # use citro3d::math::{Projection, ClipPlanes, Matrix4};
     /// #
-    /// let mtx: Matrix = Projection::orthographic(
+    /// let mtx: Matrix4 = Projection::orthographic(
     ///     0.0..240.0,
     ///     0.0..400.0,
     ///     ClipPlanes {