rosu-pp 4.0.1

Difficulty and performance calculation for osu!
Documentation 
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use rosu_map::util::Pos;

use crate::{model::beatmap::BeatmapAttributesExt, osu::object::OsuObject};

use super::object::OsuDifficultyObject;

const BROKEN_GAMEFIELD_ROUNDING_ALLOWANCE: f32 = 1.00041;

/// Fields around the scaling of hit objects.
///
/// osu!lazer stores these in each hit object but since all objects share the
/// same scaling (w.r.t. difficulty & performance), we store them only once.
pub struct ScalingFactor {
    /// `NORMALIZED_RADIUS / Radius`
    pub factor: f32,
    pub radius: f64,
    pub scale: f32,
}

impl ScalingFactor {
    pub fn new(cs: f32) -> Self {
        let scale = (f64::from(1.0_f32)
            - f64::from(0.7_f32) * BeatmapAttributesExt::difficulty_range_value(f64::from(cs)))
            as f32
            / 2.0
            * BROKEN_GAMEFIELD_ROUNDING_ALLOWANCE;

        let radius = f64::from(OsuObject::OBJECT_RADIUS * scale);
        let factor = OsuDifficultyObject::NORMALIZED_RADIUS as f32 / radius as f32;

        Self {
            factor,
            radius,
            scale,
        }
    }

    pub fn stack_offset(&self, stack_height: i32) -> Pos {
        let stack_offset = stack_height as f32 * self.scale * -6.4;

        Pos::new(stack_offset, stack_offset)
    }
}