/// <summary>
/// Get the tangents applied to the mesh, or create and cache them if not yet initialized.
/// </summary>
/// <returns>The tangents applied to the MeshFilter.sharedMesh. If the tangents array length does not match the vertex count, null is returned.</returns>
public Vector4[] GetTangents()
{
if (!HasArrays(MeshArrays.Tangent))
Normals.CalculateTangents(this);
return tangents.ToArray();
}
/// <summary>
/// Collects coincident vertices and returns a rotation calculated from the average normal and bitangent.
/// </summary>
/// <param name="mesh">The target mesh.</param>
/// <param name="indices">Vertex indices to consider in the rotation calculations.</param>
/// <returns>A rotation calculated from the average normal of each vertex.</returns>
public static Quaternion GetRotation(ProBuilderMesh mesh, IEnumerable <int> indices)
{
if (!mesh.HasArrays(MeshArrays.Normal))
{
Normals.CalculateNormals(mesh);
}
if (!mesh.HasArrays(MeshArrays.Tangent))
{
Normals.CalculateTangents(mesh);
}
var normals = mesh.normalsInternal;
var tangents = mesh.tangentsInternal;
var nrm = Vector3.zero;
var tan = Vector4.zero;
float count = 0;
foreach (var index in indices)
{
var n = normals[index];
var t = tangents[index];
nrm.x += n.x;
nrm.y += n.y;
nrm.z += n.z;
tan.x += t.x;
tan.y += t.y;
tan.z += t.z;
tan.w += t.w;
count++;
}
nrm.x /= count;
nrm.y /= count;
nrm.z /= count;
tan.x /= count;
tan.y /= count;
tan.z /= count;
tan.w /= count;
if (nrm == Vector3.zero || tan == Vector4.zero)
{
return(mesh.transform.rotation);
}
var bit = Vector3.Cross(nrm, tan * tan.w);
return(mesh.transform.rotation * Quaternion.LookRotation(nrm, bit));
}
void RefreshTangents()
{
Normals.CalculateTangents(this);
mesh.tangents = m_Tangents;
}