unindex + add barycentric coordinates

addBarycentricCoordinates.js

import buffer from 'three-buffer-vertex-data';

export default function addBarycentricCoordinates (bufferGeometry) {
  const barycentric = [];
  const attrib = bufferGeometry.getIndex() || bufferGeometry.getAttribute('position');
  const count = attrib.count / 3;
  if (count % 2 !== 0) {
    // Probably won't ever happen
    console.error('WARN: Got a weird decimal result for attribute count, skipping wireframe...');
    return;
  }

  for (let i = 0; i < count; i++) {
    barycentric.push(
      0, 0, 1,
      0, 1, 0,
      1, 0, 0
    );
  }

  // attach barycentric attribute to geometry
  buffer.attr(bufferGeometry, 'barycentric', barycentric, 3);
}

unindexBufferGeometry.js

export default function unindexBufferGeometry (bufferGeometry) {
  const index = bufferGeometry.getIndex();
  if (!index) return; // already un-indexed

  const indexArray = index.array;
  const triangleCount = indexArray.length / 3;

  const attributes = bufferGeometry.attributes;
  const newAttribData = Object.keys(attributes).map(key => {
    return {
      array: [],
      attribute: bufferGeometry.getAttribute(key)
    };
  });

  for (let i = 0; i < triangleCount; i++) {
    // indices into attributes
    const a = indexArray[i * 3 + 0];
    const b = indexArray[i * 3 + 1];
    const c = indexArray[i * 3 + 2];
    const indices = [ a, b, c ];

    // for each attribute, put vertex into unindexed list
    newAttribData.forEach(data => {
      const attrib = data.attribute;
      const dim = attrib.itemSize;
      // add [a, b, c] vertices
      for (let i = 0; i < indices.length; i++) {
        const index = indices[i];
        for (let d = 0; d < dim; d++) {
          const v = attrib.array[index * dim + d];
          data.array.push(v);
        }
      }
    });
  }
  index.array = null;
  bufferGeometry.setIndex(null);

  // now copy over new data
  newAttribData.forEach(data => {
    const newArray = new data.attribute.array.constructor(data.array);
    data.attribute.setArray(newArray);
  });
}