public static Supported3DFiles CheckFileType(ModelFileData fileData)
{
byte[] byteBuffer = new byte[100];
if (fileData.HasBytes())
{
// Has enough bytes?
if (!fileData.ReadBytes(byteBuffer, 0, 0, byteBuffer.Length))
{
return(Supported3DFiles.Unsuportted);
}
// Check if some evil being renamed some PNG file to one of the supported formats.
if (byteBuffer[0] == 137 && byteBuffer[1] == 80 && byteBuffer[2] == 78 && byteBuffer[3] == 71 && byteBuffer[4] == 13 && byteBuffer[5] == 10 && byteBuffer[6] == 26 && byteBuffer[7] == 10)
{
return(Supported3DFiles.Unsuportted);
}
// Or maybe a JPG.
if (byteBuffer[0] == 0xFF && byteBuffer[1] == 0xD8 && byteBuffer[2] == 0xFF)
{
return(Supported3DFiles.Unsuportted);
}
}
if (fileData.FileName.EndsWith(".stl", StringComparison.InvariantCultureIgnoreCase))
{
if (!fileData.HasBytes())
{
return(Supported3DFiles.STL_Binary); // Return default STL format.
}
// If doesnt start with "solid", its always binary.
if (!(Encoding.ASCII.GetString(byteBuffer, 0, 5) == "solid"))
{
return(Supported3DFiles.STL_Binary);
}
// EXCEPT, that some binary files also start with solid, so check the header and wish bad omen to whoever created such files.
string header = Encoding.ASCII.GetString(byteBuffer, 0, 100);
for (int i = 0; i < header.Length; i++)
{
if (Char.IsControl(header[i]) && header[i] != '\r' && header[i] != '\n')
{
return(Supported3DFiles.STL_Binary);
}
}
return(Supported3DFiles.STL_ASCII);
}
else if (fileData.FileName.EndsWith(".obj", StringComparison.InvariantCultureIgnoreCase))
{
return(Supported3DFiles.OBJ);
}
if (fileData.FileName.EndsWith(".3mf", StringComparison.InvariantCultureIgnoreCase))
{
return(Supported3DFiles._3MF);
}
else
{
return(Supported3DFiles.Unsuportted);
}
}
static Mesh3D ParseSTLBinary(ModelFileData fileData)
{
// STL Binary Format: https://en.wikipedia.org/wiki/STL_(file_format)#Binary_STL
if (!fileData.HasBytes())
{
return(null);
}
byte[] byteBuffer = new byte[4 * 9];
int index = 80;
int byteBufferIndex = 0;
fileData.ReadBytes(byteBuffer, index, 0, 4);
int triangleAmount = (int)System.BitConverter.ToUInt32(byteBuffer, 0); index += 4;
if (triangleAmount <= 0 || fileData.BytesLength < 80 + triangleAmount * 50)
{
return(null);
}
try
{
if (triangleAmount <= 0 || triangleAmount > 10000000)
{
throw new Exception("The STLBinary file has too many triangles.");
}
SegmentedArray <int> triangles = new SegmentedArray <int>(triangleAmount * 3);
SegmentedArray <Mesh3D.Vertexh> vertices = new SegmentedArray <Mesh3D.Vertexh>(triangleAmount * 3);
for (int i = 0; i < triangles.Length;)
{
// Skip reading the facet normal (why STL come with normals???).
index += 4 * 3;
// Triangle vertices
{
fileData.ReadBytes(byteBuffer, index, 0, byteBuffer.Length); byteBufferIndex = 0;
index += 4 * 9;
vertices[i] = new Mesh3D.Vertexh(
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex),
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex += 4),
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex += 4)
);
triangles[i] = i++;
vertices[i] = new Mesh3D.Vertexh(
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex += 4),
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex += 4),
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex += 4)
);
triangles[i] = i++;
vertices[i] = new Mesh3D.Vertexh(
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex += 4),
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex += 4),
(Half)System.BitConverter.ToSingle(byteBuffer, byteBufferIndex += 4)
);
triangles[i] = i++;
}
// Skip the remaining bytes.
index += 2;
}
return(new Mesh3D(vertices, triangles));
}
catch (Exception ex)
{
logger.Trace(ex, "Exception when processing file: {FileName}, {FileSizeKB}, {FileType}", fileData.FileName, fileData.FileSizeKB, fileData.FileType.ToString());
return(null);
}
}