bendns' repos / sine
cos/sin idk
Diffstat (limited to 'src/lib.rs')
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1 files changed, 37 insertions, 0 deletions
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+#![doc = include_str!("../README.md")]
+use std::f32::consts::{PI, TAU};
+use umath::FF32;
+const FRACT_PI_2: f32 = PI / 2.0;
+
+#[inline]
+/// Calaculates the cosine of x, approximately. cant say how approximately.
+pub fn cos(x: f32) -> f32 {
+ let x = unsafe { FF32::new(x) };
+ let mut y = x * unsafe { FF32::new(1.0 / TAU) };
+ y -= 0.25 + (y + 0.25).floor();
+ *(y * 16.0 * (y.abs() - 0.5))
+}
+
+#[inline]
+/// Calculates the sine of x, approximately. cant say how approximately.
+pub fn sin(x: f32) -> f32 {
+ cos(x - FRACT_PI_2)
+}
+
+/// extension crate for cos/sin.
+pub trait Sine {
+ /// faster cos
+ fn cosf(self) -> Self;
+ /// faster sin
+ fn sinf(self) -> Self;
+}
+
+impl Sine for f32 {
+ fn cosf(self) -> Self {
+ cos(self)
+ }
+
+ fn sinf(self) -> Self {
+ sin(self)
+ }
+}