feat(geom): add ICollate & ICopy impls, re-add/update convexHull2

packages/geom/src/api.ts

@@ -1,7 +1,10 @@
 import { ICopy } from "@thi.ng/api/api";
-import { IDistance, IMix } from "@thi.ng/vectors/api";
+import { IDistance, IMix, Vec } from "@thi.ng/vectors/api";
 
-export type SampleableVector<T> = ICopy<T> & IDistance<T> & IMix<T>;
+export type SampleableVector<T> =
+    ICopy<T> &
+    IDistance<T> &
+    IMix<T>;
 
 export interface IArea {
     /**
@@ -47,8 +50,23 @@ export interface ICentroid<T> {
     centroid(c?: T): T;
 }
 
+export interface ICollate {
+    /**
+     * Collates all points into a single buffer and remaps existing
+     * vertices (by default). Points will written from given `start`
+     * index, using layout defined by `cstride` and `estride`.
+     *
+     * @param remap
+     * @param buf
+     * @param start
+     * @param cstride
+     * @param estride
+     */
+    collate(remap?: boolean, buf?: Vec, start?: number, cstride?: number, estride?: number): this;
+}
+
 export interface IEdges<T> {
-    edges(): Iterable<T>;
+    edges(opts?: any): Iterable<T>;
 }
 
 export interface IToPolygon2 {

packages/geom/src/container2.ts

@@ -2,12 +2,20 @@ import { IObjectOf } from "@thi.ng/api/api";
 import { illegalArgs } from "@thi.ng/errors/illegal-arguments";
 import { Mat23 } from "@thi.ng/vectors/mat23";
 import { Vec2, vec2 } from "@thi.ng/vectors/vec2";
-import { IBounds, ICentroid, IVertices } from "./api";
+import {
+    IBounds,
+    ICentroid,
+    ICollate,
+    IVertices
+} from "./api";
 import { bounds } from "./func/bounds";
+import { convexHull2 } from "./func/convex-hull";
+import { Vec } from "@thi.ng/vectors/api";
 
 export class PointContainer2 implements
     IBounds<Vec2[]>,
     ICentroid<Vec2>,
+    ICollate,
     IVertices<Vec2> {
 
     points: Vec2[];
@@ -22,6 +30,23 @@ export class PointContainer2 implements
         yield* this.vertices();
     }
 
+    collate(remap = true, buf: Vec, start = 0, cstride = 1, estride = 2) {
+        if (!remap) {
+            this.points = this._copy();
+        } else {
+            const pts = this.points;
+            const n = pts.length;
+            buf = Vec2.intoBuffer(buf || new Array(start + n * estride).fill(0), pts, start, cstride, estride);
+            for (let i = 0; i < n; i++) {
+                const p = pts[i];
+                p.buf = buf;
+                p.i = start + i * estride;
+                p.s = cstride;
+            }
+        }
+        return this;
+    }
+
     vertices() {
         return this.points;
     }
@@ -44,6 +69,10 @@ export class PointContainer2 implements
         return 0;
     }
 
+    convextHull() {
+        return convexHull2(this.points);
+    }
+
     centroid(c?: Vec2): Vec2 {
         const pts = this.points;
         const num = pts.length;
@@ -87,4 +116,8 @@ export class PointContainer2 implements
         }
         return this;
     }
+
+    protected _copy() {
+        return Vec2.mapBuffer(Vec2.intoBuffer([], this.points), this.points.length);
+    }
 }

packages/geom/src/container3.ts

@@ -1,13 +1,20 @@
 import { IObjectOf } from "@thi.ng/api/api";
 import { illegalArgs } from "@thi.ng/errors/illegal-arguments";
+import { Vec } from "@thi.ng/vectors/api";
 import { Mat44 } from "@thi.ng/vectors/mat44";
 import { Vec3, vec3 } from "@thi.ng/vectors/vec3";
-import { IBounds, ICentroid, IVertices } from "./api";
+import {
+    IBounds,
+    ICentroid,
+    ICollate,
+    IVertices
+} from "./api";
 import { bounds } from "./func/bounds";
 
 export class PointContainer3 implements
     IBounds<Vec3[]>,
     ICentroid<Vec3>,
+    ICollate,
     IVertices<Vec3> {
 
     points: Vec3[];
@@ -22,6 +29,23 @@ export class PointContainer3 implements
         yield* this.vertices();
     }
 
+    collate(remap = true, buf: Vec, start = 0, cstride = 1, estride = 3) {
+        if (!remap) {
+            this.points = this._copy();
+        } else {
+            const pts = this.points;
+            const n = pts.length;
+            buf = Vec3.intoBuffer(buf || new Array(start + n * estride).fill(0), pts, start, cstride, estride);
+            for (let i = 0; i < n; i++) {
+                const p = pts[i];
+                p.buf = buf;
+                p.i = start + i * estride;
+                p.s = cstride;
+            }
+        }
+        return this;
+    }
+
     vertices() {
         return this.points;
     }
@@ -88,4 +112,8 @@ export class PointContainer3 implements
         }
         return this;
     }
+
+    protected _copy() {
+        return Vec3.mapBuffer(Vec3.intoBuffer([], this.points), this.points.length);
+    }
 }

packages/geom/src/func/convex-hull.ts

@@ -0,0 +1,35 @@
+import { Vec2 } from "@thi.ng/vectors/vec2";
+import { corner } from "./corner";
+
+/**
+ * Returns array of points defining the Convex Hull of `pts` using
+ * Graham Scan method.
+ *
+ * https://en.wikipedia.org/wiki/Graham_scan
+ *
+ * @param pts
+ */
+export const convexHull2 = (pts: ReadonlyArray<Vec2>) => {
+    const num = pts.length;
+    const res: Vec2[] = [];
+    let h = 0, i;
+    pts = pts.slice().sort(Vec2.comparator(0, 1));
+    const scan = (p: Vec2, thresh: number) => {
+        while (h >= thresh && corner(res[h - 2], res[h - 1], p) >= 0) {
+            res.pop();
+            h--;
+        }
+        res[h++] = p;
+    };
+    for (i = 0; i < num; i++) {
+        scan(pts[i], 2);
+    }
+    res.pop();
+    h--;
+    const h2 = h + 2;
+    for (i = num - 1; i >= 0; i--) {
+        scan(pts[i], h2);
+    }
+    res.pop();
+    return res;
+}

packages/geom/src/func/corner.ts

@@ -0,0 +1,11 @@
+import { EPS, sign1 } from "@thi.ng/vectors/math";
+import { Vec2 } from "@thi.ng/vectors/vec2";
+
+export const corner = (a: Readonly<Vec2>, b: Readonly<Vec2>, c: Readonly<Vec2>) => {
+    const ax = a.x,
+        ay = a.y;
+    return (b.x - ax) * (c.y - ay) - (c.x - ax) * (b.y - ay);
+};
+
+export const classify = (a: Readonly<Vec2>, b: Readonly<Vec2>, c: Readonly<Vec2>, eps = EPS) =>
+    sign1(corner(a, b, c), eps);

packages/geom/src/func/edges.ts

@@ -1,6 +1,6 @@
 import { wrap } from "@thi.ng/transducers/iter/wrap";
 import { partition } from "@thi.ng/transducers/xform/partition";
 
-export const edges = <T>(vertices: T[], closed = false) => {
-    return partition(2, 1, closed ? wrap(vertices, 1, false, true) : vertices);
+export const edges = <T>(vertices: ReadonlyArray<T>, closed = false) => {
+    return partition<T>(2, 1, closed ? wrap(vertices, 1, false, true) : vertices);
 };

packages/geom/src/poly2.ts

@@ -15,6 +15,10 @@ export class Polygon2 extends PointContainer2 implements
         super(points, attribs);
     }
 
+    copy() {
+        return new Polygon2(this._copy(), { ...this.attribs });
+    }
+
     edges() {
         return edges(this.vertices(), true);
     }

packages/geom/src/polyline2.ts

@@ -16,6 +16,10 @@ export class Polyline2 extends PointContainer2 implements
         super(points, attribs);
     }
 
+    copy() {
+        return new Polyline2(this._copy(), { ...this.attribs });
+    }
+
     edges() {
         return edges(this.vertices());
     }