marss 0.0.3

Mars celestial simulation crate for the MilkyWay SolarSystem workspace
Documentation 
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pub struct ElevationProvider {
    pub resolution_arcsec: f64,
    data: Vec<f64>,
    cols: usize,
    rows: usize,
}

impl ElevationProvider {
    pub fn from_heightmap(hm: &crate::terrain::heightmap::Heightmap) -> Self {
        Self {
            resolution_arcsec: 360.0 * 3600.0 / hm.width as f64,
            data: hm.data.clone(),
            cols: hm.width,
            rows: hm.height,
        }
    }

    pub fn sample(&self, lat_deg: f64, lon_deg: f64) -> f64 {
        let u = ((lon_deg + 180.0) / 360.0).clamp(0.0, 1.0);
        let v = ((90.0 - lat_deg) / 180.0).clamp(0.0, 1.0);
        let x = u * (self.cols - 1) as f64;
        let y = v * (self.rows - 1) as f64;
        let ix = (x as usize).min(self.cols - 2);
        let iy = (y as usize).min(self.rows - 2);
        let fx = x - ix as f64;
        let fy = y - iy as f64;
        let v00 = self.data[iy * self.cols + ix];
        let v10 = self.data[iy * self.cols + ix + 1];
        let v01 = self.data[(iy + 1) * self.cols + ix];
        let v11 = self.data[(iy + 1) * self.cols + ix + 1];
        v00 * (1.0 - fx) * (1.0 - fy)
            + v10 * fx * (1.0 - fy)
            + v01 * (1.0 - fx) * fy
            + v11 * fx * fy
    }
}

pub struct NotableElevation {
    pub name: &'static str,
    pub elevation_m: f64,
    pub lat_deg: f64,
    pub lon_deg: f64,
}

pub fn notable_elevations() -> Vec<NotableElevation> {
    vec![
        NotableElevation {
            name: "Olympus Mons summit",
            elevation_m: 21_900.0,
            lat_deg: 18.65,
            lon_deg: -133.8,
        },
        NotableElevation {
            name: "Hellas Planitia floor",
            elevation_m: -7_152.0,
            lat_deg: -42.7,
            lon_deg: 70.0,
        },
        NotableElevation {
            name: "Ascraeus Mons summit",
            elevation_m: 18_200.0,
            lat_deg: 11.92,
            lon_deg: -104.87,
        },
        NotableElevation {
            name: "Valles Marineris floor",
            elevation_m: -7_000.0,
            lat_deg: -14.0,
            lon_deg: -59.0,
        },
        NotableElevation {
            name: "Isidis Planitia floor",
            elevation_m: -3_800.0,
            lat_deg: 12.9,
            lon_deg: 87.0,
        },
        NotableElevation {
            name: "Argyre basin floor",
            elevation_m: -5_200.0,
            lat_deg: -49.7,
            lon_deg: -43.0,
        },
        NotableElevation {
            name: "Tharsis plateau",
            elevation_m: 10_000.0,
            lat_deg: 0.0,
            lon_deg: -110.0,
        },
    ]
}