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comparison utils/src/math.rs @ 789:b5bca9274335

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utils: Make some math functions const Sadly f32::sqrt() isn’t const, so we can’t make normalize() const nor any function which depends on it.
author Link Mauve <linkmauve@linkmauve.fr>
date Sun, 04 Jan 2026 11:49:03 +0100
parents 21b186be2590
children d005f5927447
comparison
equal deleted inserted replaced
788:f56b10812b77 789:b5bca9274335
5 inner: [[f32; 4]; 4] 5 inner: [[f32; 4]; 4]
6 } 6 }
7 7
8 impl Mat4 { 8 impl Mat4 {
9 /// Create a new matrix from a set of 16 f32. 9 /// Create a new matrix from a set of 16 f32.
10 pub fn new(inner: [[f32; 4]; 4]) -> Mat4 { 10 pub const fn new(inner: [[f32; 4]; 4]) -> Mat4 {
11 Mat4 { 11 Mat4 {
12 inner 12 inner
13 } 13 }
14 } 14 }
15 15
16 fn zero() -> Mat4 { 16 const fn zero() -> Mat4 {
17 Mat4 { 17 Mat4 {
18 inner: [[0.; 4]; 4] 18 inner: [[0.; 4]; 4]
19 } 19 }
20 } 20 }
21 21
22 fn identity() -> Mat4 { 22 const fn identity() -> Mat4 {
23 Mat4 { 23 Mat4 {
24 inner: [[1., 0., 0., 0.], 24 inner: [[1., 0., 0., 0.],
25 [0., 1., 0., 0.], 25 [0., 1., 0., 0.],
26 [0., 0., 1., 0.], 26 [0., 0., 1., 0.],
27 [0., 0., 0., 1.]] 27 [0., 0., 0., 1.]]
28 } 28 }
29 } 29 }
30 30
31 /// Immutably borrow the array of f32 inside this matrix. 31 /// Immutably borrow the array of f32 inside this matrix.
32 pub fn borrow_inner(&self) -> &[[f32; 4]; 4] { 32 pub const fn borrow_inner(&self) -> &[[f32; 4]; 4] {
33 &self.inner 33 &self.inner
34 } 34 }
35 35
36 /// Scale the matrix in 2D. 36 /// Scale the matrix in 2D.
37 pub fn scale2d(&mut self, x: f32, y: f32) { 37 pub fn scale2d(&mut self, x: f32, y: f32) {
127 tmp 127 tmp
128 } 128 }
129 } 129 }
130 130
131 /// Create an orthographic projection matrix. 131 /// Create an orthographic projection matrix.
132 pub fn ortho_2d(left: f32, right: f32, bottom: f32, top: f32) -> Mat4 { 132 pub const fn ortho_2d(left: f32, right: f32, bottom: f32, top: f32) -> Mat4 {
133 let mut mat = Mat4::identity(); 133 let mut mat = Mat4::identity();
134 mat.inner[0][0] = 2. / (right - left); 134 mat.inner[0][0] = 2. / (right - left);
135 mat.inner[1][1] = 2. / (top - bottom); 135 mat.inner[1][1] = 2. / (top - bottom);
136 mat.inner[2][2] = -1.; 136 mat.inner[2][2] = -1.;
137 mat.inner[3][0] = -(right + left) / (right - left); 137 mat.inner[3][0] = -(right + left) / (right - left);
178 [s[1], u[1], -f[1], 0.], 178 [s[1], u[1], -f[1], 0.],
179 [s[2], u[2], -f[2], 0.], 179 [s[2], u[2], -f[2], 0.],
180 [-dot(s, eye), -dot(u, eye), dot(f, eye), 1.]]) 180 [-dot(s, eye), -dot(u, eye), dot(f, eye), 1.]])
181 } 181 }
182 182
183 fn sub(a: Vec3, b: Vec3) -> Vec3 { 183 const fn sub(a: Vec3, b: Vec3) -> Vec3 {
184 [a[0] - b[0], 184 [a[0] - b[0],
185 a[1] - b[1], 185 a[1] - b[1],
186 a[2] - b[2]] 186 a[2] - b[2]]
187 } 187 }
188 188
189 fn normalize(vec: Vec3) -> Vec3 { 189 fn normalize(vec: Vec3) -> Vec3 {
190 let normal = 1. / (vec[0] * vec[0] + vec[1] * vec[1] + vec[2] * vec[2]).sqrt(); 190 let normal = 1. / (vec[0] * vec[0] + vec[1] * vec[1] + vec[2] * vec[2]).sqrt();
191 [vec[0] * normal, vec[1] * normal, vec[2] * normal] 191 [vec[0] * normal, vec[1] * normal, vec[2] * normal]
192 } 192 }
193 193
194 fn cross(a: Vec3, b: Vec3) -> Vec3 { 194 const fn cross(a: Vec3, b: Vec3) -> Vec3 {
195 [a[1] * b[2] - b[1] * a[2], 195 [a[1] * b[2] - b[1] * a[2],
196 a[2] * b[0] - b[2] * a[0], 196 a[2] * b[0] - b[2] * a[0],
197 a[0] * b[1] - b[0] * a[1]] 197 a[0] * b[1] - b[0] * a[1]]
198 } 198 }
199 199
200 fn dot(a: Vec3, b: Vec3) -> f32 { 200 const fn dot(a: Vec3, b: Vec3) -> f32 {
201 a[0] * b[0] + a[1] * b[1] + a[2] * b[2] 201 a[0] * b[0] + a[1] * b[1] + a[2] * b[2]
202 } 202 }