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import * as vtkMath from 'vtk.js/Sources/Common/Core/Math';
import vtkLine from 'vtk.js/Sources/Common/DataModel/Line';
import vtkPlane from 'vtk.js/Sources/Common/DataModel/Plane';
import vtkPriorityQueue from 'vtk.js/Sources/Common/Core/PriorityQueue';
import vtkBoundingBox from 'vtk.js/Sources/Common/DataModel/BoundingBox';
import { IntersectionState } from 'vtk.js/Sources/Common/DataModel/Line/Constants';
import {
PolygonWithPointIntersectionState,
EPSILON,
FLOAT_EPSILON,
TOLERANCE,
} from './Constants';
// ----------------------------------------------------------------------------
// Global methods
// ----------------------------------------------------------------------------
// Given the line (p0,p1), determine if the given point is located to the left
// of, on, or to the right of a line (with the function returning >0, ==0, or
// <0 respectively). The points are assumed 3D points, but projected into
// one of x-y-z planes; hence the indices axis0 and axis1 specify which plane
// the computation is to be performed on.
function pointLocation(axis0, axis1, p0, p1, point) {
return (
(p1[axis0] - p0[axis0]) * (point[axis1] - p0[axis1]) -
(point[axis0] - p0[axis0]) * (p1[axis1] - p0[axis1])
);
}
//------------------------------------------------------------------------------
function pointInPolygon(point, vertices, bounds, normal) {
// Do a quick bounds check to throw out trivial cases.
// winding plane.
if (
point[0] < bounds[0] ||
point[0] > bounds[1] ||
point[1] < bounds[2] ||
point[1] > bounds[3] ||
point[2] < bounds[4] ||
point[2] > bounds[5]
) {
return PolygonWithPointIntersectionState.OUTSIDE;
}
// Check that the normal is non-zero.
if (vtkMath.normalize(normal) <= FLOAT_EPSILON) {
return PolygonWithPointIntersectionState.FAILURE;
}
// Assess whether the point lies on the boundary of the polygon. Points on
// the boundary are considered inside the polygon. Need to define a small
// tolerance relative to the bounding box diagonal length of the polygon.
let tol2 =
TOLERANCE *
((bounds[1] - bounds[0]) * (bounds[1] - bounds[0]) +
(bounds[3] - bounds[2]) * (bounds[3] - bounds[2]) +
(bounds[5] - bounds[4]) * (bounds[5] - bounds[4]));
tol2 *= tol2;
tol2 = tol2 === 0.0 ? FLOAT_EPSILON : tol2;
const p0 = [];
const p1 = [];
for (let i = 0; i < vertices.length; ) {
// Check coincidence to polygon vertices
p0[0] = vertices[i++];
p0[1] = vertices[i++];
p0[2] = vertices[i++];
if (vtkMath.distance2BetweenPoints(point, p0) <= tol2) {
return PolygonWithPointIntersectionState.INSIDE;
}
// Check coincidence to polygon edges
const { distance, t } = vtkLine.distanceToLine(point, p0, p1);
if (distance <= tol2 && t > 0.0 && t < 1.0) {
return PolygonWithPointIntersectionState.INSIDE;
}
}
// If here, begin computation of the winding number. This method works for
// points/polygons arbitrarily oriented in 3D space. Hence a projection
// onto one of the x-y-z coordinate planes using the maximum normal
// component. The computation will be performed in the (axis0, axis1) plane.
let axis0;
let axis1;
if (Math.abs(normal[0]) > Math.abs(normal[1])) {
if (Math.abs(normal[0]) > Math.abs(normal[2])) {
axis0 = 1;
axis1 = 2;
} else {
axis0 = 0;
axis1 = 1;
}
} else if (Math.abs(normal[1]) > Math.abs(normal[2])) {
axis0 = 0;
axis1 = 2;
} else {
axis0 = 0;
axis1 = 1;
}
// Compute the winding number wn. If after processing all polygon edges
// wn == 0, then the point is outside. Otherwise, the point is inside the
// polygon. Process all polygon edges determining if there are ascending or
// descending crossings of the line axis1=constant.
let wn = 0;
for (let i = 0; i < vertices.length; ) {
p0[0] = vertices[i++];
p0[1] = vertices[i++];
p0[2] = vertices[i++];
if (i < vertices.length) {
p1[0] = vertices[i];
p1[1] = vertices[i + 1];
p1[2] = vertices[i + 2];
} else {
p1[0] = vertices[0];
p1[1] = vertices[1];
p1[2] = vertices[2];
}
if (p0[axis1] <= point[axis1]) {
if (p1[axis1] > point[axis1]) {
// if an upward crossing
if (pointLocation(axis0, axis1, p0, p1, point) > 0) {
// if x left of edge
++wn; // a valid up intersect, increment the winding number
}
}
} else if (p1[axis1] <= point[axis1]) {
// if a downward crossing
if (pointLocation(axis0, axis1, p0, p1, point) < 0) {
// if x right of edge
--wn; // a valid down intersect, decrement the winding number
}
}
} // Over all polygon edges
// A winding number == 0 is outside the polygon
return wn === 0
? PolygonWithPointIntersectionState.OUTSIDE
: PolygonWithPointIntersectionState.INSIDE;
}
// ---------------------------------------------------
/**
* Simple utility method for computing polygon bounds.
* Returns the sum of the squares of the dimensions.
* Requires a poly with at least one point.
*
* @param {Array<Number>|TypedArray<Number>} poly
* @param {vtkPoints} points
* @param {Bound} bounds
*/
export function getBounds(poly, points, bounds) {
const n = poly.length;
const p = [];
points.getPoint(poly[0], p);
bounds[0] = p[0];
bounds[1] = p[0];
bounds[2] = p[1];
bounds[3] = p[1];
bounds[4] = p[2];
bounds[5] = p[2];
for (let j = 1; j < n; j++) {
points.getPoint(poly[j], p);
vtkBoundingBox.addPoint(bounds, ...p);
}
const length = vtkBoundingBox.getLengths(bounds);
return vtkMath.dot(length, length);
}
// ---------------------------------------------------
/**
* Compute the normal of a polygon and return its norm.
*
* TBD: This does the same thing as vtkPolygon.computeNormal,
* but in a more generic way. Maybe we can keep the public
* static method somehow and have the private method use it instead.
*
* @param {Array<Number>|TypedArray<Number>} poly
* @param {vtkPoints} points
* @param {Vector3} normal
* @returns {Number}
*/
export function getNormal(poly, points, normal) {
normal.length = 3;
normal[0] = 0.0;
normal[1] = 0.0;
normal[2] = 0.0;
const p0 = [];
let p1 = [];
let p2 = [];
const v1 = [];
const v2 = [];
points.getPoint(poly[0], p0);
points.getPoint(poly[1], p1);
for (let j = 2; j < poly.length; j++) {
points.getPoint(poly[j], p2);
vtkMath.subtract(p2, p1, v1);
vtkMath.subtract(p0, p1, v2);
const n = [0, 0, 0];
vtkMath.cross(v1, v2, n);
vtkMath.add(normal, n, normal);
[p1, p2] = [p2, p1];
}
return vtkMath.normalize(normal);
}
// ----------------------------------------------------------------------------
// Static API
// ----------------------------------------------------------------------------
const STATIC = {
PolygonWithPointIntersectionState,
pointInPolygon,
getBounds,
getNormal,
};
// ----------------------------------------------------------------------------
// vtkPolygon methods
// ----------------------------------------------------------------------------
function vtkPolygon(publicAPI, model) {
// Set our classname
model.classHierarchy.push('vtkPolygon');
function computeNormal() {
const v1 = [0, 0, 0];
const v2 = [0, 0, 0];
model.normal = [0, 0, 0];
const anchor = [...model.firstPoint.point];
let point = model.firstPoint;
for (let i = 0; i < model.pointCount; i++) {
vtkMath.subtract(point.point, anchor, v1);
vtkMath.subtract(point.next.point, anchor, v2);
const n = [0, 0, 0];
vtkMath.cross(v1, v2, n);
vtkMath.add(model.normal, n, model.normal);
point = point.next;
}
return vtkMath.normalize(model.normal);
}
function computeMeasure(point) {
const v1 = [0, 0, 0];
const v2 = [0, 0, 0];
const v3 = [0, 0, 0];
const v4 = [0, 0, 0];
vtkMath.subtract(point.point, point.previous.point, v1);
vtkMath.subtract(point.next.point, point.point, v2);
vtkMath.subtract(point.previous.point, point.next.point, v3);
vtkMath.cross(v1, v2, v4);
const area = vtkMath.dot(v4, model.normal);
if (area <= 0) {
return -1;
}
const perimeter = vtkMath.norm(v1) + vtkMath.norm(v2) + vtkMath.norm(v3);
return (perimeter * perimeter) / area;
}
function canRemoveVertex(point) {
if (model.pointCount <= 3) {
return true;
}
const previous = point.previous;
const next = point.next;
const v = [0, 0, 0];
vtkMath.subtract(next.point, previous.point, v);
const sN = [0, 0, 0];
vtkMath.cross(v, model.normal, sN);
vtkMath.normalize(sN);
if (vtkMath.norm(sN) === 0) {
return false;
}
let val = vtkPlane.evaluate(sN, previous.point, next.next.point);
// eslint-disable-next-line no-nested-ternary
let currentSign = val > EPSILON ? 1 : val < -EPSILON ? -1 : 0;
let oneNegative = currentSign < 0 ? 1 : 0;
for (
let vertex = next.next.next;
vertex.id !== previous.id;
vertex = vertex.next
) {
const previousVertex = vertex.previous;
val = vtkPlane.evaluate(sN, previous.point, vertex.point);
// eslint-disable-next-line no-nested-ternary
const sign = val > EPSILON ? 1 : val < -EPSILON ? -1 : 0;
if (sign !== currentSign) {
if (!oneNegative) {
oneNegative = sign <= 0 ? 1 : 0;
}
if (
vtkLine.intersection(
previous.point,
next.point,
vertex.point,
previousVertex.point,
[0],
[0]
) === IntersectionState.YES_INTERSECTION
) {
return false;
}
currentSign = sign;
}
}
return oneNegative === 1;
}
function removePoint(point, queue) {
model.pointCount -= 1;
const previous = point.previous;
const next = point.next;
model.tris = model.tris.concat(point.point);
model.tris = model.tris.concat(next.point);
model.tris = model.tris.concat(previous.point);
previous.next = next;
next.previous = previous;
queue.deleteById(previous.id);
queue.deleteById(next.id);
const previousMeasure = computeMeasure(previous);
if (previousMeasure > 0) {
queue.push(previousMeasure, previous);
}
const nextMeasure = computeMeasure(next);
if (nextMeasure > 0) {
queue.push(nextMeasure, next);
}
if (point.id === model.firstPoint.id) {
model.firstPoint = next;
}
}
function earCutTriangulation() {
computeNormal();
const vertexQueue = vtkPriorityQueue.newInstance();
let point = model.firstPoint;
for (let i = 0; i < model.pointCount; i++) {
const measure = computeMeasure(point);
if (measure > 0) {
vertexQueue.push(measure, point);
}
point = point.next;
}
while (model.pointCount > 2 && vertexQueue.length() > 0) {
if (model.pointCount === vertexQueue.length()) {
// convex
const pointToRemove = vertexQueue.pop();
removePoint(pointToRemove, vertexQueue);
} else E{
// concave
const pointToRemove = vertexQueue.pop();
if (canRemoveVertex(pointToRemove)) {
removePoint(pointToRemove, vertexQueue);
}
}
}
return model.pointCount <= 2;
}
publicAPI.triangulate = () => {
Iif (!model.firstPoint) {
return null;
}
return earCutTriangulation();
};
publicAPI.setPoints = (points) => {
model.pointCount = points.length;
model.firstPoint = {
id: 0,
point: points[0],
next: null,
previous: null,
};
let currentPoint = model.firstPoint;
for (let i = 1; i < model.pointCount; i++) {
currentPoint.next = {
id: i,
point: points[i],
next: null,
previous: currentPoint,
};
currentPoint = currentPoint.next;
}
model.firstPoint.previous = currentPoint;
currentPoint.next = model.firstPoint;
};
publicAPI.getPointArray = () => model.tris;
}
// ----------------------------------------------------------------------------
// Object factory
// ----------------------------------------------------------------------------
const DEFAULT_VALUES = {
firstPoint: null,
pointCount: 0,
tris: [],
};
// ----------------------------------------------------------------------------
export function extend(publicAPI, model, initialValues = {}) {
Object.assign(model, DEFAULT_VALUES, initialValues);
// Build VTK API
macro.obj(publicAPI, model);
vtkPolygon(publicAPI, model);
}
// ----------------------------------------------------------------------------
export const newInstance = macro.newInstance(extend, 'vtkPolygon');
// ----------------------------------------------------------------------------
export default { newInstance, extend, ...STATIC };
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