// Copyright (c) 2019 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

// The default mesh is only half a car. Flip Y and append to the vertices.
export function mirrorMesh({indices, positions, normals}) {
  const indexSize = indices.length;
  const vertexSize = positions.length;
  const vertexCount = vertexSize / 3;

  const indices2 = new Uint16Array(indexSize * 2);
  const positions2 = new Float32Array(vertexSize * 2);
  const normals2 = new Float32Array(vertexSize * 2);

  indices2.set(indices);
  indices2.set(indices, indexSize);
  positions2.set(positions);
  positions2.set(positions, vertexSize);
  normals2.set(normals);
  normals2.set(normals, vertexSize);

  // Flip y
  for (let i = 0; i < vertexSize; i += 3) {
    positions2[i + 1] *= -1;
    normals2[i + 1] *= -1;
  }
  // Indices for the 2nd half
  for (let i = 0; i < indexSize; i++) {
    indices2[i] += vertexCount;
  }
  return {indices: indices2, positions: positions2, normals: normals2};
}
