public List <Mesh> BuildMesh(List <Mesh> meshesToUse = null)
{
var meshes = new List <Mesh>();
int curTriangle = 0;
int curAvailableTriangle = triangle.Count;
int curAvailableVertex = kMaxVertex;
int curAvailableIndex = kMaxIndex;
int curLine = 0;
int curAvailableLine = line.Count;
int curMesh = 0;
while (true)
{
int numTriangle = ProcessShapes(ref curAvailableTriangle, ref curAvailableVertex, ref curAvailableIndex, MeshData.kVertexPerTriangle, MeshData.kIndexPerTriangle);
int numLine = ProcessShapes(ref curAvailableLine, ref curAvailableVertex, ref curAvailableIndex, MeshData.kVertexPerLine, MeshData.kIndexPerLine);
if (numTriangle > 0 || numLine > 0)
{
MeshData md = new MeshData(numLine, numTriangle);
if (numTriangle > 0)
{
md.Add(triangle, curTriangle, curTriangle + numTriangle);
curTriangle += numTriangle;
}
if (numLine > 0)
{
md.Add(line, curLine, curLine + numLine);
curLine += numLine;
}
meshes.Add(md.CreateMesh(
meshesToUse != null && meshesToUse.Count > curMesh
? meshesToUse[curMesh]
: null
));
curAvailableVertex = kMaxVertex;
curAvailableIndex = kMaxIndex;
++curMesh;
}
else
{
break;
}
}
if (meshesToUse != null)
{
for (int i = curMesh; i != meshesToUse.Count; ++i)
{
UnityEngine.Object.DestroyImmediate(meshesToUse[i]);
meshesToUse[i] = null;
}
}
return(meshes);
}
/// <summary>
/// Parse read bytes from a STL binary file.
/// </summary>
/// <param name="bytes">Read bytes.</param>
/// <param name="normalSmoothAngleThreshold">Angle where normal angles below this angle is
/// interpreted as a smooth surface.</param>
/// <returns>Array of meshes parsed from <paramref name="bytes"/>.</returns>
public static Mesh[] ReadBinary(byte[] bytes,
float normalSmoothAngleThreshold)
{
// Specification from https://en.wikipedia.org/wiki/STL_(file_format).
// -------------------------------------------------------------------
// UINT8[80] – Header
// UINT32 – Number of triangles
//
// foreach triangle
// REAL32[3] – Normal vector
// REAL32[3] – Vertex 1
// REAL32[3] – Vertex 2
// REAL32[3] – Vertex 3
// UINT16 – Attribute byte count
// end
// -------------------------------------------------------------------
var meshes = new List <Mesh>();
using (var memStream = new MemoryStream(bytes))
using (var binStream = new BinaryReader(memStream)) {
binStream.ReadBytes(80);
int numTriangles = (int)binStream.ReadUInt32();
var meshData = new MeshData(3 * numTriangles, normalSmoothAngleThreshold);
var vertexBuffer = new Vector3[3];
for (int globalTriangleNumber = 0; globalTriangleNumber < numTriangles; ++globalTriangleNumber)
{
var normal = binStream.ReadVector3().ToLeftHanded();
for (int triangleVertexIndex = 0; triangleVertexIndex < 3; ++triangleVertexIndex)
{
vertexBuffer[triangleVertexIndex] = binStream.ReadVector3().ToLeftHanded();
}
meshData.Add(normal, vertexBuffer);
// TODO STL: Parse color if bit index 15 is set (or not in some implementations) ("hack").
binStream.ReadUInt16();
if (meshData.Vertices.Count >= ushort.MaxValue - 3)
{
meshes.Add((Mesh)meshData);
}
}
if (meshData.IsValid)
{
meshes.Add((Mesh)meshData);
}
}
return(meshes.ToArray());
}
