public void PolygonEarClipping()
{
/* 6 --- 1
* / /
* / /
* 5 2
* \ \
* \ \
* 4 --- 3
*/
var vertices = new List <Pnt>
{
new Pnt(double.NaN, double.NaN, double.NaN), // Dummy vertex to test indexing
new Pnt(1.0, -1.0, -0.0),
new Pnt(-0.2, 0.0, 0.0),
new Pnt(1.0, 1.0, 0.0),
new Pnt(0.0, 1.0, 0.0),
new Pnt(-1.0, 0.0, 0.0),
new Pnt(0.0, -1.0, -0.0),
};
var indices = new List <int>
{
1, 2, 3, 4, 5, 6
};
var expected = new List <int>
{
1, 6, 5,
5, 4, 3,
5, 3, 2,
5, 2, 1
};
var triangulator = new EarClippingTriangulator();
var result = triangulator.DoTriangulation(vertices, indices);
Assert.NotNull(result);
Assert.That(expected.SequenceEqual(result));
// Change direction
indices = new List <int>
{
6, 5, 4, 3, 2, 1
};
expected = new List <int>
{
1, 6, 5,
5, 4, 3,
5, 3, 2,
5, 2, 1
};
result = triangulator.DoTriangulation(vertices, indices);
Assert.NotNull(result);
Assert.That(expected.SequenceEqual(result));
}
//--------------------------------------------------------------------------------------------------
public static bool Import(string fileName, out IEnumerable <Body> bodies, bool singleBody)
{
bodies = null;
using var fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
var vertices = new List <Pnt>();
var currentObject = ObjectDescription.Create();
var objectDescList = new List <ObjectDescription>();
var reader = new ObjAsciiReader(fs);
// Read
string cmd;
while (reader.MoveNext(out cmd))
{
switch (cmd)
{
case "o":
case "g":
if (currentObject.Indices.Count != 0)
{
objectDescList.Add(currentObject);
}
currentObject = ObjectDescription.Create();
reader.GetObjectOrGroup(out currentObject.Name);
break;
case "v":
if (!reader.GetVertex(out var vertex))
{
return(false);
}
vertices.Add(vertex);
break;
case "f":
case "fo":
if (!reader.GetFace(out var indices))
{
continue;
}
// Negative indices must be correctly re-assigned
// -1 => vertices.Count
// -2 => vertices.Count-1
for (int i = 0; i < indices.Length; i++)
{
if (indices[i] < 0)
{
indices[i] = vertices.Count + (indices[i] + 1);
}
}
if (indices.Length == 3)
{
currentObject.Indices.AddRange(indices.Take(3).Select(index => index - 1)); // Correct lower bound (from 1 to 0)
}
else
{
var triangulator = new EarClippingTriangulator();
var result = triangulator.DoTriangulation(vertices, indices.Select(index => index - 1)); // Correct lower bound (from 1 to 0)
if (result != null)
{
currentObject.Indices.AddRange(result);
}
}
break;
}
}
if (currentObject.Indices.Count != 0)
{
objectDescList.Add(currentObject);
}
_CreateFaces(objectDescList, vertices);
bodies = _CreateBodies(objectDescList, Path.GetFileNameWithoutExtension(fileName), singleBody);
// Cleanup
fs.Close();
return(true);
}
//--------------------------------------------------------------------------------------------------
bool IBodyImporter.DoImport(string fileName, out IEnumerable <Body> bodies)
{
bodies = null;
try
{
using (var fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
{
var vertices = new List <Pnt>();
var currentObject = ObjectDescription.Create();
var objectDescList = new List <ObjectDescription>();
var reader = new ObjAsciiReader(fs);
// Read
string cmd;
while (reader.MoveNext(out cmd))
{
switch (cmd)
{
case "o":
case "g":
if (currentObject.Indices.Count != 0)
{
objectDescList.Add(currentObject);
}
currentObject = ObjectDescription.Create();
reader.GetObjectOrGroup(out currentObject.Name);
break;
case "v":
if (!reader.GetVertex(out var vertex))
{
return(false);
}
vertices.Add(vertex);
break;
case "f":
case "fo":
if (!reader.GetFace(out var indices))
{
continue;
}
// Negative indices must be correctly re-assigned
// -1 => vertices.Count
// -2 => vertices.Count-1
for (int i = 0; i < indices.Length; i++)
{
if (indices[i] < 0)
{
indices[i] = vertices.Count + (indices[i] + 1);
}
}
if (indices.Length == 3)
{
currentObject.Indices.AddRange(indices.Take(3).Select(index => index - 1)); // Correct lower bound (from 1 to 0)
}
else
{
var triangulator = new EarClippingTriangulator();
var result = triangulator.DoTriangulation(vertices, indices.Select(index => index - 1)); // Correct lower bound (from 1 to 0)
if (result != null)
{
currentObject.Indices.AddRange(result);
}
}
break;
}
}
if (currentObject.Indices.Count != 0)
{
objectDescList.Add(currentObject);
}
// Create Faces
foreach (var objectDesc in objectDescList)
{
// Extract used vertices
var usedVertices = new List <Pnt>();
var indexMap = new Dictionary <int, int>();
for (int index = 0; index < objectDesc.Indices.Count; index++)
{
int newIndex;
int oldIndex = objectDesc.Indices[index];
if (!indexMap.TryGetValue(oldIndex, out newIndex))
{
newIndex = usedVertices.Count;
usedVertices.Add(vertices[oldIndex]);
indexMap.Add(oldIndex, newIndex);
}
objectDesc.Indices[index] = newIndex;
}
// Create shape
objectDesc.Face = TriangulationHelper.CreateFaceFromTriangulation(new TriangulationData(objectDesc.Indices.ToArray(), usedVertices.ToArray()));
}
// Create bodies
var bodyList = new List <Body>();
string bodyName = Path.GetFileNameWithoutExtension(fileName);
if (Settings.ImportSingleBody)
{
var compound = new TopoDS_Compound();
var builder = new BRep_Builder();
builder.MakeCompound(compound);
foreach (var objectDesc in objectDescList)
{
builder.Add(compound, objectDesc.Face);
}
var body = Body.Create(Mesh.Create(compound));
body.Name = bodyName;
bodyList.Add(body);
}
else
{
int index = 1;
foreach (var objectDesc in objectDescList)
{
var body = Body.Create(Mesh.Create(objectDesc.Face));
if (!objectDesc.Name.IsNullOrWhiteSpace())
{
body.Name = objectDesc.Name;
}
else
{
body.Name = $"{bodyName}_{index++}";
}
bodyList.Add(body);
}
}
bodies = bodyList;
// Cleanup
fs.Close();
}
return(true);
}
catch (Exception e)
{
Messages.Exception($"Exception occured while importing {fileName}.", e);
return(false);
}
}
