three-stdlib/misc/TubePainter.js

stand-alone library of threejs examples

import { BufferAttribute, DynamicDrawUsage, BufferGeometry, MeshStandardMaterial, Mesh, Vector3, Color, Matrix4 } from "three";
function TubePainter() {
  const BUFFER_SIZE = 1e6 * 3;
  const positions = new BufferAttribute(new Float32Array(BUFFER_SIZE), 3);
  positions.usage = DynamicDrawUsage;
  const normals = new BufferAttribute(new Float32Array(BUFFER_SIZE), 3);
  normals.usage = DynamicDrawUsage;
  const colors = new BufferAttribute(new Float32Array(BUFFER_SIZE), 3);
  colors.usage = DynamicDrawUsage;
  const geometry = new BufferGeometry();
  geometry.setAttribute("position", positions);
  geometry.setAttribute("normal", normals);
  geometry.setAttribute("color", colors);
  geometry.drawRange.count = 0;
  const material = new MeshStandardMaterial({
    vertexColors: true
  });
  const mesh = new Mesh(geometry, material);
  mesh.frustumCulled = false;
  function getPoints(size2) {
    const PI2 = Math.PI * 2;
    const sides = 10;
    const array = [];
    const radius = 0.01 * size2;
    for (let i = 0; i < sides; i++) {
      const angle = i / sides * PI2;
      array.push(new Vector3(Math.sin(angle) * radius, Math.cos(angle) * radius, 0));
    }
    return array;
  }
  const vector1 = new Vector3();
  const vector2 = new Vector3();
  const vector3 = new Vector3();
  const vector4 = new Vector3();
  const color = new Color(16777215);
  let size = 1;
  function stroke(position1, position2, matrix12, matrix22) {
    if (position1.distanceToSquared(position2) === 0)
      return;
    let count2 = geometry.drawRange.count;
    const points = getPoints(size);
    for (let i = 0, il = points.length; i < il; i++) {
      const vertex1 = points[i];
      const vertex2 = points[(i + 1) % il];
      vector1.copy(vertex1).applyMatrix4(matrix22).add(position2);
      vector2.copy(vertex2).applyMatrix4(matrix22).add(position2);
      vector3.copy(vertex2).applyMatrix4(matrix12).add(position1);
      vector4.copy(vertex1).applyMatrix4(matrix12).add(position1);
      vector1.toArray(positions.array, (count2 + 0) * 3);
      vector2.toArray(positions.array, (count2 + 1) * 3);
      vector4.toArray(positions.array, (count2 + 2) * 3);
      vector2.toArray(positions.array, (count2 + 3) * 3);
      vector3.toArray(positions.array, (count2 + 4) * 3);
      vector4.toArray(positions.array, (count2 + 5) * 3);
      vector1.copy(vertex1).applyMatrix4(matrix22).normalize();
      vector2.copy(vertex2).applyMatrix4(matrix22).normalize();
      vector3.copy(vertex2).applyMatrix4(matrix12).normalize();
      vector4.copy(vertex1).applyMatrix4(matrix12).normalize();
      vector1.toArray(normals.array, (count2 + 0) * 3);
      vector2.toArray(normals.array, (count2 + 1) * 3);
      vector4.toArray(normals.array, (count2 + 2) * 3);
      vector2.toArray(normals.array, (count2 + 3) * 3);
      vector3.toArray(normals.array, (count2 + 4) * 3);
      vector4.toArray(normals.array, (count2 + 5) * 3);
      color.toArray(colors.array, (count2 + 0) * 3);
      color.toArray(colors.array, (count2 + 1) * 3);
      color.toArray(colors.array, (count2 + 2) * 3);
      color.toArray(colors.array, (count2 + 3) * 3);
      color.toArray(colors.array, (count2 + 4) * 3);
      color.toArray(colors.array, (count2 + 5) * 3);
      count2 += 6;
    }
    geometry.drawRange.count = count2;
  }
  const up = new Vector3(0, 1, 0);
  const point1 = new Vector3();
  const point2 = new Vector3();
  const matrix1 = new Matrix4();
  const matrix2 = new Matrix4();
  function moveTo(position) {
    point1.copy(position);
    matrix1.lookAt(point2, point1, up);
    point2.copy(position);
    matrix2.copy(matrix1);
  }
  function lineTo(position) {
    point1.copy(position);
    matrix1.lookAt(point2, point1, up);
    stroke(point1, point2, matrix1, matrix2);
    point2.copy(point1);
    matrix2.copy(matrix1);
  }
  function setSize(value) {
    size = value;
  }
  let count = 0;
  function update() {
    const start = count;
    const end = geometry.drawRange.count;
    if (start === end)
      return;
    positions.updateRange.offset = start * 3;
    positions.updateRange.count = (end - start) * 3;
    positions.needsUpdate = true;
    normals.updateRange.offset = start * 3;
    normals.updateRange.count = (end - start) * 3;
    normals.needsUpdate = true;
    colors.updateRange.offset = start * 3;
    colors.updateRange.count = (end - start) * 3;
    colors.needsUpdate = true;
    count = geometry.drawRange.count;
  }
  return {
    mesh,
    moveTo,
    lineTo,
    setSize,
    update
  };
}
export {
  TubePainter
};
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