separate out visualizer library

1 files changed, 165 insertions, 0 deletions

diff --git a/web/pw-visualizer/src/voronoi/voronoi.ts b/web/pw-visualizer/src/voronoi/voronoi.ts
new file mode 100644
index 0000000..a63bc9a
--- /dev/null
+++ b/web/pw-visualizer/src/voronoi/voronoi.ts
@@ -0,0 +1,165 @@
+import type { Shader } from "../webgl/shader";
+import type { BBox, Point } from "./voronoi-core";
+import Voronoi from "./voronoi-core";
+import { DefaultRenderable } from "../webgl/renderer";
+import { IndexBuffer, VertexBuffer } from "../webgl/buffer";
+import { VertexBufferLayout, VertexArray } from "../webgl/vertexBufferLayout";
+
+function arcctg(x: number): number { return Math.PI / 2 - Math.atan(x); }
+
+function to_key(p: Point): string {
+    return [p.x, p.y] + "";
+}
+
+function round_point(center: Point, point: Point, amount_fn = (b: number) => 0.7): Point {
+    const d = dist(center, point, true);
+    const x = center.x + amount_fn(d) * (point.x - center.x);
+    const y = center.y + amount_fn(d) * (point.y - center.y);
+    return { 'x': x, 'y': y };
+}
+
+function median_point(c: Point, p: Point, n: Point, d = 0.1): number[] {
+    const dd = 1.0 - 2 * d;
+    return [
+        dd * c.x + d * p.x + d * n.x,
+        dd * c.y + d * p.y + d * n.y,
+    ]
+}
+
+function build_point_map(es: Voronoi.HalfEdge[]): (point: Point) => Point {
+    const mean = es.map(e => dist(e.getStartpoint(), e.getEndpoint())).reduce((a, b) => a + b, 0) / es.length;
+    const map = {};
+
+    for (let edge of es) {
+        const start = edge.getStartpoint();
+        const end = edge.getEndpoint();
+
+        if (dist(start, end) < 0.03 * mean) {    // These points have to be merged
+            const middle = { 'x': (start.x + end.x) / 2, 'y': (start.y + end.y) / 2 };
+            map[to_key(start)] = middle;
+            map[to_key(end)] = middle;
+        }
+    }
+
+    return (p) => map[to_key(p)] || p;
+}
+
+function get_round_fn(dist_mean: number, amount = 0.7): (d: number) => number {
+    return (d) => arcctg((d - dist_mean) / dist_mean) / Math.PI + 0.6;
+}
+
+function dist(a: Point, b: Point, norm = false): number {
+    const dx = a.x - b.x;
+    const dy = a.y - b.y;
+    if (norm) return Math.sqrt(dx * dx + dy * dy);
+    return dx * dx + dy * dy;
+}
+
+export class VoronoiBuilder {
+    inner: DefaultRenderable;
+
+    vor: Voronoi;
+    planets: Point[];
+
+
+    constructor(gl: WebGLRenderingContext, shader: Shader, planets: Point[], bbox: BBox) {
+        this.vor = new Voronoi();
+        this.planets = planets;
+
+        const ib = new IndexBuffer(gl, []);
+        const vb = new VertexBuffer(gl, []);
+
+        const layout = new VertexBufferLayout();
+        layout.push(gl.FLOAT, 2, 4, "a_pos");
+        layout.push(gl.FLOAT, 2, 4, "a_center");
+        layout.push(gl.FLOAT, 1, 4, "a_own");
+        layout.push(gl.FLOAT, 1, 4, "a_intensity");
+
+        const vao = new VertexArray();
+        vao.addBuffer(vb, layout);
+
+        this.inner = new DefaultRenderable(ib, vao, shader, [], {});
+
+        this.resize(gl, bbox);
+    }
+
+    getRenderable(): DefaultRenderable {
+        return this.inner;
+    }
+
+    resize(gl: WebGLRenderingContext, bbox: BBox) {
+        const start = new Date().getTime();
+
+        // This voronoi sorts the planets, then owners don't align anymore
+        const own_map = {};
+        this.planets.forEach((p, i) => own_map[to_key(p)] = i);
+
+        const vor = this.vor.compute(this.planets, bbox);
+
+        const attrs = [];
+        const ids = [];
+
+        let vertCount = 0;
+
+        for (let i = 0; i < vor.cells.length; i++) {
+            const cell = vor.cells[i];
+            const planetId = own_map[to_key(cell.site)];
+            const point_map = build_point_map(cell.halfedges);
+
+            const centerId = vertCount++;
+
+            attrs.push(cell.site.x, cell.site.y);
+            attrs.push(cell.site.x, cell.site.y);
+            attrs.push(planetId);
+            attrs.push(1);
+
+            const dist_mean = cell.halfedges.map(e => {
+                const start = e.getStartpoint();
+                const end = e.getEndpoint();
+                return dist(cell.site, start, true) + dist(cell.site, { 'x': (start.x + end.x) / 2, 'y': (start.y + end.y) / 2 }, true)
+            }).reduce((a, b) => a + b, 0) / cell.halfedges.length / 2;
+            const round_fn = get_round_fn(dist_mean);
+
+            for (let edge of cell.halfedges) {
+                let start = point_map(edge.getStartpoint());
+                let end = point_map(edge.getEndpoint());
+                let center = { 'x': (start.x + end.x) / 2, 'y': (start.y + end.y) / 2 };
+
+                if (to_key(start) == to_key(end)) continue;
+
+                start = round_point(cell.site, start, round_fn);
+                center = round_point(cell.site, center, round_fn);
+                end = round_point(cell.site, end, round_fn);
+
+                ids.push(centerId);
+                ids.push(vertCount++);
+                attrs.push(start.x, start.y);
+                attrs.push(cell.site.x, cell.site.y);
+                attrs.push(planetId);
+                attrs.push(0);
+
+                ids.push(vertCount++);
+                attrs.push(center.x, center.y);
+                attrs.push(cell.site.x, cell.site.y);
+                attrs.push(planetId);
+                attrs.push(0);
+
+                ids.push(centerId);
+                ids.push(vertCount - 1);
+
+                ids.push(vertCount++);
+                attrs.push(end.x, end.y);
+                attrs.push(cell.site.x, cell.site.y);
+                attrs.push(planetId);
+                attrs.push(0);
+            }
+        }
+
+        this.inner.updateIndexBuffer(gl, ids);
+        this.inner.updateVAOBuffer(gl, 0, attrs);
+
+        console.log(`Vor things took ${new Date().getTime() - start} ms!`)
+    }
+}
+
+export default VoronoiBuilder;
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