private static int MergeDuplicatePositions(IList <Vector3F> positions, float positionTolerance, int[] positionRemap)
{
Debug.Assert(positions != null);
Debug.Assert(positions.Count > 0);
Debug.Assert(positionTolerance > 0);
Debug.Assert(positionRemap == null || positionRemap.Length == positions.Count);
// Create working data.
int numberOfVertices = positions.Count;
var data = new WeldVertex[numberOfVertices];
for (int i = 0; i < numberOfVertices; i++)
{
Vector3F position = positions[i];
data[i].Position = position;
data[i].OriginalIndex = i;
data[i].SortValue = Math.Abs(position.X) + Math.Abs(position.Y) + Math.Abs(position.Z);
data[i].MergedIndex = -1;
}
// Sort positions by absolute component sum of position |X|+|Y|+|Z|.
Array.Sort(data, WeldVertex.CompareSortValue);
int numberOfMergedVertices = 0;
// Loop over positions. Try to merge each vertex with the next positions in the array.
for (int i = 0; i < numberOfVertices; i++)
{
// For positions that have already been merged, the index was set to > -1.
if (data[i].MergedIndex >= 0)
{
// Vertex is a duplicate. - Nothing to do.
continue;
}
// Now, we compare vertex i against the next positions in the array.
for (int j = i + 1; j < numberOfVertices; j++)
{
// We can stop comparing if the SortValue differs by more than 3 * epsilon.
if (data[j].SortValue - data[i].SortValue > 3 * positionTolerance)
{
break;
}
//if (Vector3F.AreNumericallyEqual(data[i].Position, data[j].Position, positionTolerance))
// Optimized version: (Probably does not work for infinite float values!)
float delta = Math.Abs(data[i].Position.X - data[j].Position.X);
if (delta <= positionTolerance)
{
delta = Math.Abs(data[i].Position.Y - data[j].Position.Y);
if (delta <= positionTolerance)
{
delta = Math.Abs(data[i].Position.Z - data[j].Position.Z);
if (delta <= positionTolerance)
{
// Vertex positions are near each other and should be merged.
numberOfMergedVertices++;
data[j].MergedIndex = data[i].OriginalIndex;
}
}
}
}
}
if (numberOfMergedVertices == 0)
{
return(0);
}
// Sort by original index.
Array.Sort(data, WeldVertex.CompareOriginalIndex);
// Rebuild positions (omitting the merged positions).
positions.Clear();
if (positionRemap == null)
{
for (int i = 0; i < numberOfVertices; i++)
{
if (data[i].MergedIndex < 0)
{
positions.Add(data[i].Position);
}
}
}
else
{
// Rebuild positions and at the same time we fill the position remap table.
for (int i = 0; i < numberOfVertices; i++)
{
if (data[i].MergedIndex < 0)
{
positionRemap[i] = positions.Count;
positions.Add(data[i].Position);
}
else
{
positionRemap[i] = -1;
}
}
// Now, fill in the other entries in the index redirection table.
for (int i = 0; i < numberOfVertices; i++)
{
if (data[i].MergedIndex >= 0)
{
positionRemap[i] = positionRemap[data[i].MergedIndex];
}
Debug.Assert(positionRemap[i] != -1);
}
}
return(numberOfMergedVertices);
}
public static int CompareOriginalIndex(WeldVertex v0, WeldVertex v1)
{
return(v0.OriginalIndex.CompareTo(v1.OriginalIndex));
}
public int MergedIndex; // >= 0 if this vertex was merged.
public static int CompareSortValue(WeldVertex v0, WeldVertex v1)
{
return(v0.SortValue.CompareTo(v1.SortValue));
}
public static int CompareSortValue(WeldVertex v0, WeldVertex v1)
{
return v0.SortValue.CompareTo(v1.SortValue);
}
public float SortValue; // Absolute component sum of position: |X|+|Y|+|Z|
#endregion Fields
#region Methods
public static int CompareOriginalIndex(WeldVertex v0, WeldVertex v1)
{
return v0.OriginalIndex.CompareTo(v1.OriginalIndex);
}
private static int MergeDuplicatePositions(IList<Vector3F> positions, float positionTolerance, int[] positionRemap)
{
Debug.Assert(positions != null);
Debug.Assert(positions.Count > 0);
Debug.Assert(positionTolerance > 0);
Debug.Assert(positionRemap == null || positionRemap.Length == positions.Count);
// Create working data.
int numberOfVertices = positions.Count;
var data = new WeldVertex[numberOfVertices];
for (int i = 0; i < numberOfVertices; i++)
{
Vector3F position = positions[i];
data[i].Position = position;
data[i].OriginalIndex = i;
data[i].SortValue = Math.Abs(position.X) + Math.Abs(position.Y) + Math.Abs(position.Z);
data[i].MergedIndex = -1;
}
// Sort positions by absolute component sum of position |X|+|Y|+|Z|.
Array.Sort(data, WeldVertex.CompareSortValue);
int numberOfMergedVertices = 0;
// Loop over positions. Try to merge each vertex with the next positions in the array.
for (int i = 0; i < numberOfVertices; i++)
{
// For positions that have already been merged, the index was set to > -1.
if (data[i].MergedIndex >= 0)
{
// Vertex is a duplicate. - Nothing to do.
continue;
}
// Now, we compare vertex i against the next positions in the array.
for (int j = i + 1; j < numberOfVertices; j++)
{
// We can stop comparing if the SortValue differs by more than 3 * epsilon.
if (data[j].SortValue - data[i].SortValue > 3 * positionTolerance)
break;
//if (Vector3F.AreNumericallyEqual(data[i].Position, data[j].Position, positionTolerance))
// Optimized version: (Probably does not work for infinite float values!)
float delta = Math.Abs(data[i].Position.X - data[j].Position.X);
if (delta <= positionTolerance)
{
delta = Math.Abs(data[i].Position.Y - data[j].Position.Y);
if (delta <= positionTolerance)
{
delta = Math.Abs(data[i].Position.Z - data[j].Position.Z);
if (delta <= positionTolerance)
{
// Vertex positions are near each other and should be merged.
numberOfMergedVertices++;
data[j].MergedIndex = data[i].OriginalIndex;
}
}
}
}
}
if (numberOfMergedVertices == 0)
return 0;
// Sort by original index.
Array.Sort(data, WeldVertex.CompareOriginalIndex);
// Rebuild positions (omitting the merged positions).
positions.Clear();
if (positionRemap == null)
{
for (int i = 0; i < numberOfVertices; i++)
if (data[i].MergedIndex < 0)
positions.Add(data[i].Position);
}
else
{
// Rebuild positions and at the same time we fill the position remap table.
for (int i = 0; i < numberOfVertices; i++)
{
if (data[i].MergedIndex < 0)
{
positionRemap[i] = positions.Count;
positions.Add(data[i].Position);
}
else
{
positionRemap[i] = -1;
}
}
// Now, fill in the other entries in the index redirection table.
for (int i = 0; i < numberOfVertices; i++)
{
if (data[i].MergedIndex >= 0)
positionRemap[i] = positionRemap[data[i].MergedIndex];
Debug.Assert(positionRemap[i] != -1);
}
}
return numberOfMergedVertices;
}
