start adding public api

Author: g-harel

public/gen.ts

@@ -0,0 +1,29 @@
+import {genBlob} from "../internal/blobs";
+import {rand} from "../internal/rand";
+import {Shape} from "../internal/types";
+
+export interface GenOptions {
+    seed: string | number;
+    extraPoints: number;
+    randomness: number;
+}
+
+export interface Blob {
+    shape: Shape;
+}
+
+export const gen = (opt: GenOptions) => {
+    const rgen = rand(String(opt.seed));
+
+    // Scale of random movement increases as randomness approaches infinity.
+    // randomness = 0   -> rangeStart = 1
+    // randomness = 2   -> rangeStart = 0.8333
+    // randomness = 5   -> rangeStart = 0.6667
+    // randomness = 10  -> rangeStart = 0.5
+    // randomness = 20  -> rangeStart = 0.3333
+    // randomness = 50  -> rangeStart = 0.1667
+    // randomness = 100 -> rangeStart = 0.0909
+    const rangeStart = 1 / (1 + Math.abs(opt.randomness) / 10);
+
+    return genBlob(3 + Math.abs(opt.extraPoints), () => rangeStart + rgen() * (1 - rangeStart));
+};