From 03e52b011537f064beb7d6deb024246616ee3b74 Mon Sep 17 00:00:00 2001
From: Johan Andersson <repi@repi.se>
Date: Thu, 29 Oct 2020 18:56:32 +0100
Subject: [PATCH] Workaround const_mat3 issue

---
 src/macros.rs | 74 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 69 insertions(+), 5 deletions(-)

diff --git a/src/macros.rs b/src/macros.rs
index e5b1dd5b..1401c575 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -61,20 +61,84 @@ macro_rules! const_mat2 {
 /// const IDENTITY: Mat3 = const_mat3!([1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]);
 /// ```
 #[macro_export]
+//#[cfg(not(target_arch = "spirv"))]
 macro_rules! const_mat3 {
-    ($f32x9:expr) => {
-        unsafe { $crate::f32::F32x9Cast { f32x9: $f32x9 }.mat3 }
-    };
-    ($col0:expr, $col1:expr, $col2:expr) => {
+    ($f32x9:expr) => {{
+        #[cfg(not(target_arch = "spirv"))]
+        unsafe {
+            $crate::f32::F32x9Cast { f32x9: $f32x9 }.mat3
+        }
+
+        // special path for SPIRV, without this we get:
+        //
+        //    error[E0080]: it is undefined behavior to use this value
+        //    --> glam-rs\src\f32\mat3.rs:6:1
+        //     |
+        //   6 | const ZERO: Mat3 = const_mat3!([0.0; 9]);
+        //     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered uninitialized bytes at .z_axis.1, but expected initialized plain (non-pointer) bytes
+        //     |
+        //     = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+        #[cfg(target_arch = "spirv")]
+        $crate::Mat3 {
+            x_axis: Vec3($f32x9[0], $f32x9[1], $f32x9[2]),
+            y_axis: Vec3($f32x9[3], $f32x9[4], $f32x9[5]),
+            z_axis: Vec3($f32x9[6], $f32x9[7], $f32x9[8]),
+        }
+    }};
+    ($col0:expr, $col1:expr, $col2:expr) => {{
+        #[cfg(not(target_arch = "spirv"))]
         unsafe {
             $crate::f32::F32x9Cast {
                 f32x3x3: [$col0, $col1, $col2],
             }
             .mat3
         }
+
+        // special path for SPIRv, without this we get:
+        //
+        //    error[E0080]: it is undefined behavior to use this value
+        //      --> glam-rs\src\f32\mat3.rs:7:1
+        //      |
+        //    7 | const IDENTITY: Mat3 = const_mat3!([1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]);
+        //      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered uninitialized bytes at .z_axis.1, but expected initialized
+        //    plain (non-pointer) bytes
+        //      |
+        //      = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+        #[cfg(target_arch = "spirv")]
+        $crate::Mat3 {
+            x_axis: Vec3($col0[0], $col0[1], $col0[2]),
+            y_axis: Vec3($col1[0], $col1[1], $col1[2]),
+            z_axis: Vec3($col2[0], $col2[1], $col2[2]),
+        }
+    }};
+}
+/*
+/// Creates a `Mat3` from three column vectors that can be used to initialize a constant value.
+///
+/// ```
+/// use glam::{const_mat3, Mat3};
+/// const ZERO: Mat3 = const_mat3!([0.0; 9]);
+/// const IDENTITY: Mat3 = const_mat3!([1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]);
+/// ```
+#[macro_export]
+#[cfg(target_arch = "spirv")]
+macro_rules! const_mat3 {
+    ($f32x9:expr) => {
+        $crate::Mat3 {
+            x_axis: Vec3($f32x9[0], $f32x9[1], $f32x9[2]),
+            y_axis: Vec3($f32x9[3], $f32x9[4], $f32x9[5]),
+            z_axis: Vec3($f32x9[6], $f32x9[7], $f32x9[8]),
+        }
+    };
+    ($col0:expr, $col1:expr, $col2:expr) => {
+        $crate::Mat3 {
+            x_axis: Vec3($col0[0], $col0[1], $col0[2]),
+            y_axis: Vec3($col1[0], $col1[1], $col1[2]),
+            z_axis: Vec3($col2[0], $col2[1], $col2[2]),
+        }
     };
 }
-
+*/
 /// Creates a `Mat4` from four column vectors that can be used to initialize a constant value.
 ///
 /// ```