titanss 0.0.2

Titan celestial simulation crate for the MilkyWay SolarSystem workspace
Documentation 
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use crate::{MAX_SURFACE_TEMP_K, MIN_SURFACE_TEMP_K, TITAN_DAY_HOURS};

#[derive(Debug, Clone, Copy, PartialEq)]
pub struct ThermalEnvironment {
    pub local_time_hours: f64,
    pub latitude_deg: f64,
    pub shadowed: bool,
}

impl ThermalEnvironment {
    pub fn surface_temperature_k(&self) -> f64 {
        if self.shadowed {
            return MIN_SURFACE_TEMP_K;
        }
        let mean = (MIN_SURFACE_TEMP_K + MAX_SURFACE_TEMP_K) * 0.5;
        let amp = (MAX_SURFACE_TEMP_K - MIN_SURFACE_TEMP_K) * 0.3;
        let diurnal_phase = (self.local_time_hours / TITAN_DAY_HOURS).fract();
        let solar_term = -((diurnal_phase * std::f64::consts::TAU).cos());
        let latitude_cooling = self.latitude_deg.abs() * 0.35;
        (mean + amp * solar_term.max(-0.95) - latitude_cooling)
            .clamp(MIN_SURFACE_TEMP_K, MAX_SURFACE_TEMP_K)
    }
}

pub fn thermal_cycle_span_k(latitude_deg: f64) -> f64 {
    let noon = ThermalEnvironment {
        local_time_hours: TITAN_DAY_HOURS * 0.5,
        latitude_deg,
        shadowed: false,
    }
    .surface_temperature_k();
    let midnight = ThermalEnvironment {
        local_time_hours: 0.0,
        latitude_deg,
        shadowed: false,
    }
    .surface_temperature_k();
    noon - midnight
}