earth/rendering/
ocean_rendering.rs

1pub struct OceanParams {
2    pub wind_speed_ms: f64,
3    pub wind_direction: [f64; 2],
4    pub fetch_km: f64,
5    pub depth_m: f64,
6    pub grid_size: u32,
7    pub patch_size_m: f64,
8    pub gravity: f64,
9}
10impl Default for OceanParams {
11    fn default() -> Self {
12        Self {
13            wind_speed_ms: 10.0,
14            wind_direction: [1.0, 0.0],
15            fetch_km: 500.0,
16            depth_m: 4000.0,
17            grid_size: 256,
18            patch_size_m: 1000.0,
19            gravity: *crate::SURFACE_GRAVITY,
20        }
21    }
22}
23pub struct OceanSpectrum {
24    pub heights: Vec<f64>,
25    pub normals: Vec<[f64; 3]>,
26    pub grid_size: u32,
27}
28impl OceanParams {
29    pub fn phillips_spectrum(&self, kx: f64, ky: f64) -> f64 {
30        let k_sq = kx * kx + ky * ky;
31        if k_sq < 1e-12 {
32            return 0.0;
33        }
34        let k = k_sq.sqrt();
35        let l = self.wind_speed_ms * self.wind_speed_ms / self.gravity;
36        let k_dot_w = (kx * self.wind_direction[0] + ky * self.wind_direction[1]) / k;
37        let damping = 0.001;
38        let phillips = ((-1.0 / (k * l).powi(2)).exp() / k_sq.powi(2))
39            * k_dot_w.powi(2)
40            * (-k_sq * damping * damping).exp();
41        phillips.max(0.0)
42    }
43    pub fn generate_spectrum(&self) -> OceanSpectrum {
44        let n = self.grid_size as usize;
45        let mut heights = vec![0.0; n * n];
46        let normals = vec![[0.0, 1.0, 0.0]; n * n];
47        for j in 0..n {
48            for i in 0..n {
49                let kx =
50                    (2.0 * std::f64::consts::PI * (i as f64 - n as f64 / 2.0)) / self.patch_size_m;
51                let ky =
52                    (2.0 * std::f64::consts::PI * (j as f64 - n as f64 / 2.0)) / self.patch_size_m;
53                heights[j * n + i] = self.phillips_spectrum(kx, ky).sqrt();
54            }
55        }
56        OceanSpectrum {
57            heights,
58            normals,
59            grid_size: self.grid_size,
60        }
61    }
62    pub fn dispersion(&self, k: f64) -> f64 {
63        (self.gravity * k * (k * self.depth_m).tanh()).sqrt()
64    }
65}
earth/rendering/ocean_rendering.rs

earth/rendering/
ocean_rendering.rs
