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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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