public static Mesh GenerateSurfaceVolume <T>(VolumeBuffer <T> vol, Func <T, float> signTest, Vector3 relativeCameraPos, DynamicFieldModel optionalModel = null)
{
int tetCorners = 4;
Dictionary <int, int> ndxToVertex = new Dictionary <int, int> ();
List <int> triangles = new List <int> ();
List <int> quads = new List <int> ();
float[] signes = new float[tetCorners];
List <int> edgesInTetra = new List <int> ();
VolumeHeader h2 = new VolumeHeader(new Int3(2, 2, 2));
foreach (var ndx in vol.AllIndices3())
{
if ((ndx.X != 0) && (ndx.Y != 0) && (ndx.Z != 0))
{
var start = ndx.Add(new Int3(-1, -1, -1));
foreach (var ts in TetrasInCube)
{
int countPos = 0, countNeg = 0;
int signKey = 0;
for (int cornerIndex = 0; cornerIndex < ts.Length; cornerIndex++)
{
var lndx = ts[cornerIndex];
var cur = AddInvertTileOffset3(start, (h2.LinearToCubic(lndx)));
var sv = signTest(vol.Read(cur));
if (sv >= 0.0f)
{
countPos++;
signKey |= (1 << cornerIndex);
}
else
{
countNeg++;
}
signes [cornerIndex] = sv;
}
if ((countPos > 0) && (countNeg > 0))
{
edgesInTetra.Clear();
// we have something in this tetrahedra!
for (int ei = 0; ei < VolumeTetrahedraSurfacer.EdgesInTetra.Length; ei += 2)
{
var ef = VolumeTetrahedraSurfacer.EdgesInTetra [ei + 0];
var et = VolumeTetrahedraSurfacer.EdgesInTetra [ei + 1];
if (((signes [ef]) * (signes [et])) < 0.0f)
{
// we have something on this edge!
var tf = ts[ef];
var tt = ts[et];
var vf = AddInvertTileOffset3(start, h2.LinearToCubic(tf));
var vt = AddInvertTileOffset3(start, h2.LinearToCubic(tt));
int encoded = PackVoxelEdgeIdSorted(vol.Header, vf, vt);
edgesInTetra.Add(encoded);
}
}
int prevVid = -1, prevPrevVid = -1, pppv = -1;
foreach (var ee in edgesInTetra)
{
int vid;
if (ndxToVertex.ContainsKey(ee))
{
vid = ndxToVertex [ee];
}
else
{
vid = ndxToVertex.Count;
ndxToVertex.Add(ee, vid);
}
if (edgesInTetra.Count == 3)
{
triangles.Add(vid);
}
else if (edgesInTetra.Count == 4)
{
quads.Add(vid);
}
else
{
Debug.Assert(false, "Really?? c=" + edgesInTetra.Count);
}
pppv = prevPrevVid;
prevPrevVid = prevVid;
prevVid = vid;
}
}
}
}
}
List <Vector3> vertices = new List <Vector3> ();
List <Vector3> vertexSigns = new List <Vector3> ();
List <Vector4> vertexTangents = null;
if (optionalModel != null)
{
vertexTangents = new List <Vector4> ();
}
Vector3 invScale = new Vector3(1.0f / (vol.Size.X - 1), 1.0f / (vol.Size.Y - 1), 1.0f / (vol.Size.Z - 1));
foreach (var kv in ndxToVertex)
{
// setup vertices from edge data:
var packed = kv.Key;
var vid = kv.Value;
while (vertices.Count <= vid)
{
vertices.Add(Vector3.zero);
vertexSigns.Add(Vector3.zero);;
if (optionalModel != null)
{
vertexTangents.Add(Vector4.zero);
}
}
Int3 a3, b3;
UnpackVoxelEdgeId(vol.Header, packed, out a3, out b3);
var wa = signTest(vol.Read(a3));
var wb = signTest(vol.Read(b3));
var wab = Mathf.Abs(wa) / (Mathf.Abs(wa) + Mathf.Abs(wb));
var pos = Vector3.Lerp(a3.AsVector3(), b3.AsVector3(), wab); //0.5f); // TODO: weight value based on signed root
var upos = new Vector3(pos.x * invScale.x, pos.y * invScale.y, pos.z * invScale.z) - (Vector3.one * 0.5f);
vertices [vid] = upos;
vertexSigns [vid] = (a3.AsVector3() - b3.AsVector3()) * Mathf.Sign(wa - wb);
if (optionalModel != null)
{
var ta = CalcFlowTangent(optionalModel, optionalModel.FieldsCells.Read(a3));
var tb = CalcFlowTangent(optionalModel, optionalModel.FieldsCells.Read(b3));
vertexTangents [vid] = Vector4.Lerp(ta, tb, wab); // ((ta + tb) *0.5f);
}
}
for (int qi = 0; qi < quads.Count; qi += 4)
{
// ensure quad covers whole space (a and b must be furthest from each other):
var a = vertices[quads[qi + 0]];
var b = vertices[quads[qi + 1]];
var c = vertices[quads[qi + 2]];
var d = vertices[quads[qi + 3]];
// add triangle a-b-c:
triangles.Add(quads[qi + 0]);
triangles.Add(quads[qi + 1]);
triangles.Add(quads[qi + 2]);
triangles.Add(quads[qi + 1]);
triangles.Add(quads[qi + 3]);
triangles.Add(quads[qi + 2]);
}
var trisToSort = new List <SortTri> ();
for (int i = 0; i < triangles.Count; i += 3)
{
// ensure triangle is oriented correctly:
var a = vertices[triangles[i + 0]];
var b = vertices[triangles[i + 1]];
var c = vertices[triangles[i + 2]];
var n = Vector3.Cross(b - a, c - b);
if (Vector3.Dot(vertexSigns [triangles [i + 0]], n) >= 0.0f)
{
SwapListValues(triangles, i + 1, i + 2);
}
// add triangle to list
SortTri tri;
tri.I0 = triangles [i + 0];
tri.I1 = triangles [i + 1];
tri.I2 = triangles [i + 2];
tri.DistFromCam = (relativeCameraPos - ((a + b + c) * (1.0f / 3.0f))).magnitude;
trisToSort.Add(tri);
}
// sort the triangles:
if (true)
{
trisToSort.Sort((a, b) => - (a.DistFromCam.CompareTo(b.DistFromCam)));
triangles.Clear();
foreach (var t in trisToSort)
{
triangles.Add(t.I0);
triangles.Add(t.I1);
triangles.Add(t.I2);
}
}
Mesh result = new Mesh();
//Debug.Log ("Meshing info: verts=" + vertices.Count + " tris=" + triangles.Count);
result.SetVertices(vertices);
if (optionalModel != null)
{
result.SetTangents(vertexTangents);
}
result.triangles = (triangles.ToArray());
result.RecalculateNormals();
return(result);
}
