alex/beta-minecraft-rust

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//! Port of `MathHelper`, including its lookup-table trigonometry.

use std::sync::LazyLock;

static SIN_TABLE: LazyLock<Box<[f32]>> = LazyLock::new(|| {
    (0..65536)
        .map(|i| (f64::from(i) * std::f64::consts::PI * 2.0 / 65536.0).sin() as f32)
        .collect()
});

pub fn sin(value: f32) -> f32 {
    SIN_TABLE[((value * 10430.378) as i32 & 0xFFFF) as usize]
}

pub fn cos(value: f32) -> f32 {
    SIN_TABLE[((value * 10430.378 + 16384.0) as i32 & 0xFFFF) as usize]
}

pub fn floor_f32(value: f32) -> i32 {
    let truncated = value as i32;
    if value < truncated as f32 {
        truncated.wrapping_sub(1)
    } else {
        truncated
    }
}

pub fn floor_f64(value: f64) -> i32 {
    let truncated = value as i32;
    if value < f64::from(truncated) {
        truncated.wrapping_sub(1)
    } else {
        truncated
    }
}