private static void GenerateFace(OctreeNode <NodeParms> node, MeshBuilder_IntegerVertex mb, ref Int16Triple[] tempArray, BitMap3d bmp)
{
InitVoxelPositionForNodeRange(node.XMin, node.XMax, node.YMin, node.YMax, node.ZMin, node.ZMax, ref tempArray);
//需要找到该节点的端点位置
byte cubeConfig = 0;
for (int pi = 0; pi < 8; pi++)
{
if (InRange(bmp, tempArray[pi].X, tempArray[pi].Y, tempArray[pi].Z) &&
IsWhite(bmp, tempArray[pi].X, tempArray[pi].Y, tempArray[pi].Z))
{
cubeConfig |= PointIndexToFlag[pi];
}
}
int index = 0;
while (MCTable.TriTable[cubeConfig, index] != -1)
{
int ei1 = MCTable.TriTable[cubeConfig, index];
int ei2 = MCTable.TriTable[cubeConfig, index + 1];
int ei3 = MCTable.TriTable[cubeConfig, index + 2];
Int16Triple p1 = GetIntersetedPointAtEdge(node, ei1, OctreeTable.NormalTypeIdToNormal[node.Parms.NormalTypeId], node.Parms.D);
Int16Triple p2 = GetIntersetedPointAtEdge(node, ei2, OctreeTable.NormalTypeIdToNormal[node.Parms.NormalTypeId], node.Parms.D);
Int16Triple p3 = GetIntersetedPointAtEdge(node, ei3, OctreeTable.NormalTypeIdToNormal[node.Parms.NormalTypeId], node.Parms.D);
mb.AddTriangle(p1, p2, p3);
index += 3;
}
}//对非叶子节点的超体元的抽取需要参考MCTable求取被截断边的信息
public void AddTriangle(Int16Triple p0, Int16Triple p1, Int16Triple p2)
{
int p0i;
int p1i;
int p2i;
int index = 0;
bool hasValue;
hasValue = hashMap.GetHashValue(p0.X, p0.Y, p0.Z, ref index);
if (!hasValue)
{
p0i = mesh.AddVertex(new Point3d(p0.X, p0.Y, p0.Z));
hashMap.SetHashValue(p0.X, p0.Y, p0.Z, p0i);
}
else
{
p0i = index;
}
hasValue = hashMap.GetHashValue(p1.X, p1.Y, p1.Z, ref index);
if (!hasValue)
{
p1i = mesh.AddVertex(new Point3d(p1.X, p1.Y, p1.Z));
hashMap.SetHashValue(p1.X, p1.Y, p1.Z, p1i);
}
else
{
p1i = index;
}
hasValue = hashMap.GetHashValue(p2.X, p2.Y, p2.Z, ref index);
if (!hasValue)
{
p2i = mesh.AddVertex(new Point3d(p2.X, p2.Y, p2.Z));
hashMap.SetHashValue(p2.X, p2.Y, p2.Z, p2i);
}
else
{
p2i = index;
}
if (p0i != p1i && p0i != p2i && p1i != p2i)
{
Triangle t = new Triangle(p0i, p1i, p2i);
mesh.AddFace(t);
}
}
}//对非叶子节点的超体元的抽取需要参考MCTable求取被截断边的信息
private static void GenerateFaceLeaf(OctreeNode <NodeParms> node, MeshBuilder_IntegerVertex mb, ref Int16Triple[] tempArray, BitMap3d bmp)
{
for (int k = 0; k < 8; k++)
{
tempArray[k].X = node.XMin + PointIndexToPointDelta[k].X;
tempArray[k].Y = node.YMin + PointIndexToPointDelta[k].Y;
tempArray[k].Z = node.ZMin + PointIndexToPointDelta[k].Z;
}
byte value = node.Parms.Config;
int index = 0;
while (SMCTable.TableFat[value, index] != -1)
{
Int16Triple t0 = tempArray[SMCTable.TableFat[value, index]];
Int16Triple t1 = tempArray[SMCTable.TableFat[value, index + 1]];
Int16Triple t2 = tempArray[SMCTable.TableFat[value, index + 2]];
mb.AddTriangle(t0, t1, t2);
index += 3;
}
}//对叶子节点的单位体元的抽取和SMC算法中的抽取一致
public static Mesh GenerateSurface(BitMap3d bmp)
{
int width = bmp.width;
int height = bmp.height;
int depth = bmp.depth;
Int16Triple[] tempArray = new Int16Triple[8];
#region CreateTree
RegionOctree <NodeParms> otree = new RegionOctree <NodeParms>(width, height, depth);
Queue <OctreeNode <NodeParms> > nodequeue = new Queue <OctreeNode <NodeParms> >();
for (int k = 0; k < depth - 1; k++)
{
for (int j = 0; j < height - 1; j++)
{
for (int i = 0; i < width - 1; i++)
{
byte value = 0;
for (int pi = 0; pi < 8; pi++)
{
tempArray[pi].X = i + PointIndexToPointDelta[pi].X;
tempArray[pi].Y = j + PointIndexToPointDelta[pi].Y;
tempArray[pi].Z = k + PointIndexToPointDelta[pi].Z;
if (InRange(bmp, tempArray[pi].X, tempArray[pi].Y, tempArray[pi].Z) &&
IsWhite(bmp, tempArray[pi].X, tempArray[pi].Y, tempArray[pi].Z))
{
value |= PointIndexToFlag[pi];
}
}
if (value != 0 && value != 255)
{
OctreeNode <NodeParms> leafnode = otree.CreateToLeafNode(i, j, k);
leafnode.Parms = new NodeParms();
leafnode.Parms.Config = value;
leafnode.Parms.NormalTypeId = OctreeTable.ConfigToNormalTypeId[value];
leafnode.Parms.D = CaculateDFromNormalAndCoord(i, j, k, value);
nodequeue.Enqueue(leafnode.Parent);
}
}
}
}
#endregion
#region Shrink
while (nodequeue.Count != 0)
{
OctreeNode <NodeParms> node = nodequeue.Dequeue();
byte normalType = OctreeTable.NormalNotSimple;
int D = int.MinValue;
if (CanMergeNode(node, ref normalType, ref D))
{
node.Parms = new NodeParms();
//node.Parms.Config = GetConfigFromChildren(node.Children);
node.Parms.NormalTypeId = normalType;
node.Parms.D = D;
nodequeue.Enqueue(node.Parent);
}
}
#endregion
#region ExtractTriangles
MeshBuilder_IntegerVertex mb = new MeshBuilder_IntegerVertex(width + 1, height + 1, depth + 1);
nodequeue.Enqueue(otree.Root);
while (nodequeue.Count != 0)
{
OctreeNode <NodeParms> node = nodequeue.Dequeue();
if (node.Parms == null)
{
for (int i = 0; i < 8; i++)
{
if (node.Children[i] != null)
{
nodequeue.Enqueue(node.Children[i]);
}
}
}
else
{
if (node.Parms.NormalTypeId != OctreeTable.NormalNotSimple)
{
if (node.IsLeaf())
{
GenerateFaceLeaf(node, mb, ref tempArray, bmp);
}
else
{
GenerateFace(node, mb, ref tempArray, bmp);
}
}
else
{
if (node.IsLeaf())
{
GenerateFaceLeaf(node, mb, ref tempArray, bmp);
}
else
{
for (int i = 0; i < 8; i++)
{
if (node.Children[i] != null)
{
nodequeue.Enqueue(node.Children[i]);
}
}
}
}
}
}//采用层次遍历寻找需要抽取三角片的节点
#endregion
return(mb.GetMesh());
}
private static Int16Triple GetIntersetedPointAtEdge(OctreeNode <NodeParms> node, int edgeIndex, Int16Triple normal, int d)
{
int x = 0, y = 0, z = 0;
switch (edgeIndex)
{
case 0: { x = node.XMin; y = node.YMax + 1; return(new Int16Triple(x, y, (d - normal.X * x - normal.Y * y) / normal.Z)); }
case 2: { x = node.XMin; y = node.YMin; return(new Int16Triple(x, y, (d - normal.X * x - normal.Y * y) / normal.Z)); }
case 4: { x = node.XMax + 1; y = node.YMax + 1; return(new Int16Triple(x, y, (d - normal.X * x - normal.Y * y) / normal.Z)); }
case 6: { x = node.XMax + 1; y = node.YMin; return(new Int16Triple(x, y, (d - normal.X * x - normal.Y * y) / normal.Z)); }
case 8: { y = node.YMax + 1; z = node.ZMax + 1; return(new Int16Triple((d - normal.Y * y - normal.Z * z) / normal.X, y, z)); }
case 9: { y = node.YMax + 1; z = node.ZMin; return(new Int16Triple((d - normal.Y * y - normal.Z * z) / normal.X, y, z)); }
case 10: { y = node.YMin; z = node.ZMin; return(new Int16Triple((d - normal.Y * y - normal.Z * z) / normal.X, y, z)); }
case 11: { y = node.YMin; z = node.ZMax + 1; return(new Int16Triple((d - normal.Y * y - normal.Z * z) / normal.X, y, z)); }
case 1: { x = node.XMin; z = node.ZMin; return(new Int16Triple(x, (d - normal.X * x - normal.Z * z) / normal.Y, z)); }
case 3: { x = node.XMin; z = node.ZMax + 1; return(new Int16Triple(x, (d - normal.X * x - normal.Z * z) / normal.Y, z)); }
case 5: { x = node.XMax + 1; z = node.ZMin; return(new Int16Triple(x, (d - normal.X * x - normal.Z * z) / normal.Y, z)); }
case 7: { x = node.XMax + 1; z = node.ZMax + 1; return(new Int16Triple(x, (d - normal.X * x - normal.Z * z) / normal.Y, z)); }
default: throw new Exception();
}
}