Fast poisson sampling

Cargo.toml

@@ -65,11 +65,13 @@ num-integer = { version = "0.1.46", optional = true }
 dmi = { version = "0.3.5", optional = true }
 tracy_full = { version = "1.8.0", optional = true }
 ammonia = { version = "4.0.0", optional = true }
+fast_poisson = { version = "0.5.2", optional = true }
 
 [features]
 default = [
     "acreplace",
     "batchnoise",
+    "fast_poisson_sample",
     "cellularnoise",
     "dmi",
     "file",
@@ -89,6 +91,7 @@ default = [
 all = [
     "acreplace",
     "batchnoise",
+    "fast_poisson_sample",
     "cellularnoise",
     "dmi",
     "file",
@@ -117,6 +120,7 @@ acreplace = ["aho-corasick"]
 batchnoise = ["dbpnoise"]
 cellularnoise = ["rand", "rayon"]
 dmi = ["png", "image", "dep:dmi"]
+fast_poisson_sample = ["fast_poisson"]
 file = []
 git = ["gix", "chrono"]
 http = ["reqwest", "serde", "serde_json", "once_cell", "jobs"]

dmsrc/noise.dm

@@ -1 +1,2 @@
 #define rustg_noise_get_at_coordinates(seed, x, y) RUSTG_CALL(RUST_G, "noise_get_at_coordinates")(seed, x, y)
+#define rustg_noise_poisson_sample(seed, x, y, r) RUSTG_CALL(RUST_G, "generate_poisson_sample")(seed, x, y, r)

src/noise_gen.rs

@@ -1,7 +1,9 @@
+use fast_poisson::Poisson2D;
 use noise::{NoiseFn, Perlin};
 use std::{
     cell::RefCell,
     collections::hash_map::{Entry, HashMap},
+    fmt::Write,
 };
 
 use crate::error::Result;
@@ -36,3 +38,45 @@ fn get_at_coordinates(seed_as_str: &str, x_as_str: &str, y_as_str: &str) -> Resu
         Ok(clamped.to_string())
     })
 }
+
+byond_fn!(fn generate_poisson_sample(seed, x, y, r) {
+    get_poisson_sample(seed, x, y, r).ok()
+});
+
+fn get_poisson_sample(
+    seed_as_str: &str,
+    x_as_str: &str,
+    y_as_str: &str,
+    radius_as_str: &str,
+) -> Result<String> {
+    let x = x_as_str.parse::<f64>()?;
+    let y = y_as_str.parse::<f64>()?;
+    let r = radius_as_str.parse::<f64>()?;
+    let seed = seed_as_str.parse::<u64>()?;
+
+    let points = Poisson2D::new()
+        .with_dimensions([x, y], r)
+        .with_seed(seed)
+        .iter();
+    let mut pointmap = vec![vec![0usize; y as usize]; x as usize];
+    let mut output = String::new();
+
+    // we're just gonna truncate these to the nearest point
+    for p in points {
+        let point_x = p[0] as usize;
+        let point_y = p[1] as usize;
+        pointmap[point_x][point_y] = 1;
+    }
+
+    for row in pointmap {
+        for cell in row {
+            if cell > 0 {
+                let _ = write!(output, "1");
+            } else {
+                let _ = write!(output, "0");
+            }
+        }
+    }
+
+    Ok(output)
+}