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https://github.com/Doodle3D/Doodle3D-Slicer.git
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add demo
This commit is contained in:
Casper Lamboo
parent
59681e8023
commit
79e4acd3d1
336
comb.js
Normal file
336
comb.js
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import earcut from 'earcut';
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import { add, divide, distanceTo, normalize, subtract, normal, dot } from './src/sliceActions/helpers/vector2.js';
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function lineIntersection(a1, a2, b1, b2) {
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// source: http://mathworld.wolfram.com/Line-LineIntersection.html
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const intersection = {
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x: ((a1.x * a2.y - a1.y * a2.x) * (b1.x - b2.x) - (a1.x - a2.x) * (b1.x * b2.y - b1.y * b2.x)) / ((a1.x - a2.x) * (b1.y - b2.y) - (a1.y - a2.y) * (b1.x - b2.x)),
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y: ((a1.x * a2.y - a1.y * a2.x) * (b1.y - b2.y) - (a1.y - a2.y) * (b1.x * b2.y - b1.y * b2.x)) / ((a1.x - a2.x) * (b1.y - b2.y) - (a1.y - a2.y) * (b1.x - b2.x))
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};
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const intersectionA = subtract(intersection, a1);
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const directionA = subtract(a2, a1);
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const normalA = normalize(directionA);
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const distanceA = dot(normalA, intersectionA);
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if (distanceA < 0 || distanceA > dot(normalA, directionA)) return false;
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const intersectionB = subtract(intersection, b1);
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const directionB = subtract(b2, b1);
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const normalB = normalize(directionB);
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const distanceB = dot(normalB, intersectionB);
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if (distanceB < 0 || distanceB > dot(normalB, directionB)) return false;
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return intersection;
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}
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function pointIsInsideConvex(point, convex, vertices) {
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for (let i = 0; i < convex.length; i ++) {
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const vertexA = vertices[convex[i]];
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const vertexB = vertices[convex[(i + 1) % convex.length]];
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const n = normalize(normal(subtract(vertexB, vertexA)));
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const p = subtract(point, vertexA);
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if (dot(p, n) < 0) return false;
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}
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return true;
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}
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function decompose(polygon) {
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const vertices = polygon.reduce((points, path) => {
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points.push(...path);
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return points;
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}, []);
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const flatVertices = vertices.reduce((points, { x, y }) => {
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points.push(x, y);
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return points;
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}, []);
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let offset = 0;
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const holes = polygon
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.map(path => offset += path.length)
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.slice(0, -1);
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const flatTrainglesIndexed = earcut(flatVertices, holes);
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const convexPolygons = [];
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for (let i = 0; i < flatTrainglesIndexed.length; i += 3) {
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const face = [
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flatTrainglesIndexed[i],
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flatTrainglesIndexed[i + 1],
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flatTrainglesIndexed[i + 2]
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];
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const center = divide(face.reduce((total, point) => {
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if (!total) {
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return vertices[point];
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} else {
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return add(total, vertices[point]);
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}
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}, null), face.length);
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convexPolygons.push({
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center,
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face,
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connects: []
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});
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}
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for (let i = 0; i < convexPolygons.length; i ++) {
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for (let j = i + 1; j < convexPolygons.length; j ++) {
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const triangleIndexedA = convexPolygons[i];
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const triangleIndexedB = convexPolygons[j];
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const overlap = [];
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triangleIndexedA.face.map(index => {
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if (triangleIndexedB.face.includes(index)) overlap.push(index);
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});
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if (overlap.length === 2) {
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const distance = distanceTo(convexPolygons[i].center, convexPolygons[j].center);
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triangleIndexedA.connects.push({ to: j, edge: overlap, distance });
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triangleIndexedB.connects.push({ to: i, edge: overlap, distance });
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}
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}
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}
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return { vertices, convexPolygons };
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}
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function findClosestPath(convexPolygons, start, end, visited = [], path = []) {
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if (start === end) return [];
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visited = [...visited, start];
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const { connects } = convexPolygons[start];
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const finish = connects.find(({ to }) => to === end);
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if (finish) return [...path, finish];
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const posibilities = [];
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for (const connect of connects) {
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if (visited.includes(connect.to)) continue;
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const posibility = findClosestPath(convexPolygons, connect.to, end, visited, [...path, connect]);
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if (posibility) posibilities.push(posibility);
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}
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if (posibilities.length === 0) {
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return null;
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} else if (posibilities.length === 1) {
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return posibilities[0];
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} else if (posibilities.length > 1) {
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const distanceMap = new WeakMap();
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for (const posibility of posibilities) {
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const distance = posibility.reduce((totalDistance, connect) => totalDistance + connect.distance, 0);
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distanceMap.set(posibility, distance);
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}
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return posibilities.sort((a, b) => distanceMap.get(a) - distanceMap.get(b))[0];
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}
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}
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// const parse = string => parseFloat(string);
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// function findClosestPath(map, start, end) {
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// // dijkstra's algorithm
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// const costs = { [start]: 0 };
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// const open = { [0]: [start] };
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// const predecessors = {};
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//
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// while (open) {
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// const keys = Object.keys(open).map(parse);
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// if (keys.length === 0) break;
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// keys.sort();
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//
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// const [key] = keys;
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// const bucket = open[key];
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// const node = bucket.shift();
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// const currentCost = key;
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// const { connects } = map[node];
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//
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// if (!bucket.length) delete open[key];
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//
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// for (const { distance, to } of connects) {
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// const totalCost = distance + currentCost;
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// const vertexCost = costs[to];
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//
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// if ((typeof vertexCost === 'undefined') || (vertexCost > totalCost)) {
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// costs[to] = totalCost;
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//
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// if (!open[totalCost]) open[totalCost] = [];
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// open[totalCost].push(to);
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//
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// predecessors[to] = node;
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// }
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// }
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// }
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//
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// if (typeof costs[end] === 'undefined') return null;
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//
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// const nodes = [];
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// let node = end;
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// while (typeof node !== 'undefined') {
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// nodes.push(node);
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// node = predecessors[node];
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// }
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// nodes.reverse();
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//
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// const path = [];
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// for (let i = 1; i < nodes.length; i ++) {
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// const from = nodes[i - 1];
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// const to = nodes[i];
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//
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// const connection = map[from].connects.find(connect => connect.to === to);
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// path.push(connection);
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// }
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//
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// return path;
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// }
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function containLineInPath(path, start, end, vertices) {
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const line = [start];
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for (const { edge: [indexA, indexB] } of path) {
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const vertexA = vertices[indexA];
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const vertexB = vertices[indexB];
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const intersection = lineIntersection(start, end, vertexA, vertexB);
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if (!intersection) {
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const lastPoint = line[line.length - 1];
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const distanceA = distanceTo(lastPoint, vertexA) + distanceTo(vertexA, end);
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const distanceB = distanceTo(lastPoint, vertexB) + distanceTo(vertexB, end);
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line.push(distanceA < distanceB ? vertexA : vertexB);
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}
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}
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line.push(end);
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return line;
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}
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const canvas = document.createElement('canvas');
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document.body.appendChild(canvas);
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canvas.width = 610;
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canvas.height = 610;
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const context = canvas.getContext('2d');
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context.lineJoin = 'bevel';
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function circle(radius = 10, x = 0, y = 0, clockWise = true, segments = 40) {
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const shape = [];
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for (let rad = 0; rad < Math.PI * 2; rad += Math.PI * 2 / segments) {
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if (clockWise) {
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shape.push({ x: Math.cos(rad) * radius + x, y: Math.sin(rad) * radius + y });
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} else {
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shape.push({ x: Math.cos(rad) * radius + x, y: -Math.sin(rad) * radius + y });
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}
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}
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return shape;
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}
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const START = { x: 300, y: 300 };
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const END = { x: 300, y: 20 };
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// const CONCAVE_POLYGON = [[
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// { x: 10, y: 10 },
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// { x: 600, y: 10 },
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// { x: 500, y: 200 },
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// { x: 600, y: 600 },
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// { x: 10, y: 600 }
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// ], [
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// { x: 160, y: 120 },
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// { x: 120, y: 400 },
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// { x: 400, y: 400 }
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// ], circle(50, 300, 100, false)];
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const CONCAVE_POLYGON = [circle(300, 305, 305, true, 100), circle(50, 300, 100, false)];
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canvas.onmousedown = (event) => {
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START.x = event.offsetX;
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START.y = event.offsetY;
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compute();
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};
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canvas.onmousemove = (event) => {
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END.x = event.offsetX;
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END.y = event.offsetY;
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compute();
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};
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compute();
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function compute() {
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const { convexPolygons, vertices } = decompose(CONCAVE_POLYGON);
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const startPolygon = convexPolygons.findIndex(({ face }) => pointIsInsideConvex(START, face, vertices));
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const endPolygon = convexPolygons.findIndex(({ face }) => pointIsInsideConvex(END, face, vertices));
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if (startPolygon === -1 || endPolygon === -1) return;
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const path = findClosestPath(convexPolygons, startPolygon, endPolygon);
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if (!path) return;
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const line = containLineInPath(path, START, END, vertices);
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// draw
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context.clearRect(0, 0, canvas.width, canvas.height);
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context.beginPath();
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for (const shape of CONCAVE_POLYGON) {
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let first = true;
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for (const { x, y } of shape) {
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if (first) {
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context.moveTo(x, y);
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} else {
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context.lineTo(x, y);
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}
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first = false;
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}
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}
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context.closePath();
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context.fillStyle = 'lightgray';
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context.fill();
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// context.fillStyle = 'black';
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// context.strokeStyle = 'black';
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// context.textAlign = 'center';
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// context.textBaseline = 'middle';
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// context.lineWidth = 1;
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// context.font = '14px arial';
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// for (let i = 0; i < convexPolygons.length; i ++) {
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// const { face, center } = convexPolygons[i];
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//
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// context.beginPath();
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// for (const index of face) {
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// const vertex = vertices[index];
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// context.lineTo(vertex.x, vertex.y);
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// }
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// context.closePath();
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// context.stroke();
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//
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// context.fillText(i, center.x, center.y);
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// }
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// if (path) {
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// context.beginPath();
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// for (const { edge: [indexA, indexB] } of path) {
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// const pointA = vertices[indexA];
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// const pointB = vertices[indexB];
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// context.moveTo(pointA.x, pointA.y);
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// context.lineTo(pointB.x, pointB.y);
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// }
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// context.strokeStyle = 'blue';
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// context.lineWidth = 3;
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// context.stroke();
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// }
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if (line) {
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context.beginPath();
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for (const point of line) {
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context.lineTo(point.x, point.y);
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}
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context.strokeStyle = 'green';
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context.lineWidth = 2;
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context.stroke();
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}
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context.beginPath();
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context.arc(START.x, START.y, 3, 0, Math.PI * 2);
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context.fillStyle = 'blue';
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context.fill();
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context.beginPath();
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context.arc(END.x, END.y, 3, 0, Math.PI * 2);
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context.fillStyle = 'red';
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context.fill();
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}
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