# HG changeset patch
# User Link Mauve <linkmauve@linkmauve.fr>
# Date 1768655528 -3600
# Node ID d005f592744700cc6151c673777f3e62ba21ff5e
# Parent  b5bca9274335b1021ef1f51163f0c535d6e088de
utils: Use const_for to make more const fn

diff --git a/utils/Cargo.toml b/utils/Cargo.toml
--- a/utils/Cargo.toml
+++ b/utils/Cargo.toml
@@ -10,4 +10,5 @@
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+const_for = "0.1.5"
 getrandom = "0.3.4"
diff --git a/utils/src/math.rs b/utils/src/math.rs
--- a/utils/src/math.rs
+++ b/utils/src/math.rs
@@ -1,5 +1,7 @@
 //! Various helpers to deal with vectors and matrices.
 
+use const_for::const_for;
+
 /// A 4×4 f32 matrix type.
 pub struct Mat4 {
     inner: [[f32; 4]; 4]
@@ -34,18 +36,18 @@
     }
 
     /// Scale the matrix in 2D.
-    pub fn scale2d(&mut self, x: f32, y: f32) {
-        for i in 0..4 {
+    pub const fn scale2d(&mut self, x: f32, y: f32) {
+        const_for!(i in 0..4 => {
             self.inner[0][i] *= x;
             self.inner[1][i] *= y;
-        }
+        });
     }
 
     /// Flip the matrix.
-    pub fn flip(&mut self) {
-        for i in 0..4 {
+    pub const fn flip(&mut self) {
+        const_for!(i in 0..4 => {
             self.inner[0][i] = -self.inner[0][i];
-        }
+        });
     }
 
     /// Rotate the matrix around its x angle (in radians).
@@ -53,14 +55,14 @@
         let mut lines: [f32; 8] = [0.; 8];
         let cos_a = angle.cos();
         let sin_a = angle.sin();
-        for i in 0..4 {
+        const_for!(i in 0..4 => {
             lines[    i] = self.inner[0][i];
             lines[4 + i] = self.inner[1][i];
-        }
-        for i in 0..4 {
+        });
+        const_for!(i in 0..4 => {
             self.inner[1][i] = cos_a * lines[i] - sin_a * lines[4+i];
             self.inner[2][i] = sin_a * lines[i] + cos_a * lines[4+i];
-        }
+        });
     }
 
     /// Rotate the matrix around its y angle (in radians).
@@ -68,14 +70,14 @@
         let mut lines: [f32; 8] = [0.; 8];
         let cos_a = angle.cos();
         let sin_a = angle.sin();
-        for i in 0..4 {
+        const_for!(i in 0..4 => {
             lines[    i] = self.inner[0][i];
             lines[4 + i] = self.inner[2][i];
-        }
-        for i in 0..4 {
+        });
+        const_for!(i in 0..4 => {
             self.inner[0][i] =  cos_a * lines[i] + sin_a * lines[4+i];
             self.inner[2][i] = -sin_a * lines[i] + cos_a * lines[4+i];
-        }
+        });
     }
 
     /// Rotate the matrix around its z angle (in radians).
@@ -83,31 +85,31 @@
         let mut lines: [f32; 8] = [0.; 8];
         let cos_a = angle.cos();
         let sin_a = angle.sin();
-        for i in 0..4 {
+        const_for!(i in 0..4 => {
             lines[    i] = self.inner[0][i];
             lines[4 + i] = self.inner[1][i];
-        }
-        for i in 0..4 {
+        });
+        const_for!(i in 0..4 => {
             self.inner[0][i] = cos_a * lines[i] - sin_a * lines[4+i];
             self.inner[1][i] = sin_a * lines[i] + cos_a * lines[4+i];
-        }
+        });
     }
 
     /// Translate the matrix by a 3D offset.
-    pub fn translate(&mut self, offset: [f32; 3]) {
+    pub const fn translate(&mut self, offset: [f32; 3]) {
         let mut item: [f32; 3] = [0.; 3];
-        for i in 0..3 {
+        const_for!(i in 0..3 => {
             item[i] = self.inner[3][i] * offset[i];
-        }
-        for i in 0..3 {
-            for j in 0..4 {
+        });
+        const_for!(i in 0..3 => {
+            const_for!(j in 0..4 => {
                 self.inner[i][j] += item[i];
-            }
-        }
+            });
+        });
     }
 
     /// Translate the matrix by a 2D offset.
-    pub fn translate_2d(&mut self, x: f32, y: f32) {
+    pub const fn translate_2d(&mut self, x: f32, y: f32) {
         let offset = [x, y, 0.];
         self.translate(offset);
     }
@@ -117,13 +119,13 @@
     type Output = Mat4;
     fn mul(self, rhs: Mat4) -> Mat4 {
         let mut tmp = Mat4::zero();
-        for i in 0..4 {
-            for j in 0..4 {
-                for k in 0..4 {
+        const_for!(i in 0..4 => {
+            const_for!(j in 0..4 => {
+                const_for!(k in 0..4 => {
                     tmp.inner[i][j] += self.inner[i][k] * rhs.inner[k][j];
-                }
-            }
-        }
+                });
+            });
+        });
         tmp
     }
 }