/// <summary>
/// find and isolate independent (not connecting) parts in a mesh
/// </summary>
public static List <ExploderMesh> IsolateMeshIslands(ExploderMesh mesh)
{
var triangles = mesh.triangles;
var vertexCount = mesh.vertices.Length;
// cache mesh data
var trianglesNum = mesh.triangles.Length;
var tangents = mesh.tangents;
var colors = mesh.colors32;
var vertices = mesh.vertices;
var normals = mesh.normals;
var uvs = mesh.uv;
var useMeshTangents = tangents != null && tangents.Length > 0;
var useVertexColors = colors != null && colors.Length > 0;
var useNormals = normals != null && normals.Length > 0;
if (trianglesNum <= 3)
{
return(null);
}
ExploderUtils.Assert(trianglesNum > 3, "IsolateMeshIslands error: " + trianglesNum);
var lsHash = new LSHash(0.1f, vertexCount);
var vertHash = new int[trianglesNum];
for (int i = 0; i < trianglesNum; i++)
{
vertHash[i] = lsHash.Hash(vertices[triangles[i]]);
}
var islands = new List <HashSet <int> > {
new HashSet <int> {
vertHash[0], vertHash[1], vertHash[2]
}
};
var islandsIdx = new List <List <int> > {
new List <int>(trianglesNum)
{
0, 1, 2
}
};
var triVisited = new bool[trianglesNum];
triVisited[0] = true;
triVisited[1] = true;
triVisited[2] = true;
var currIsland = islands[0];
var currIslandIdx = islandsIdx[0];
var counter = 3;
var lastInvalidIdx = -1;
var loopCounter = 0;
while (true)
{
var foundIsland = false;
for (int j = 3; j < trianglesNum; j += 3)
{
if (triVisited[j])
{
continue;
}
if (currIsland.Contains(vertHash[j]) ||
currIsland.Contains(vertHash[j + 1]) ||
currIsland.Contains(vertHash[j + 2]))
{
currIsland.Add(vertHash[j]);
currIsland.Add(vertHash[j + 1]);
currIsland.Add(vertHash[j + 2]);
currIslandIdx.Add(j);
currIslandIdx.Add(j + 1);
currIslandIdx.Add(j + 2);
triVisited[j] = true;
triVisited[j + 1] = true;
triVisited[j + 2] = true;
counter += 3;
foundIsland = true;
}
else
{
lastInvalidIdx = j;
}
}
if (counter == trianglesNum)
{
break;
}
if (!foundIsland)
{
// create new island
currIsland = new HashSet <int> {
vertHash[lastInvalidIdx], vertHash[lastInvalidIdx + 1], vertHash[lastInvalidIdx + 2]
};
currIslandIdx = new List <int>(trianglesNum / 2)
{
lastInvalidIdx, lastInvalidIdx + 1, lastInvalidIdx + 2
};
islands.Add(currIsland);
islandsIdx.Add(currIslandIdx);
}
loopCounter++;
if (loopCounter > 100)
{
ExploderUtils.Log("10000 loop exceeded, islands: " + islands.Count);
break;
}
}
var islandNum = islands.Count;
ExploderUtils.Assert(islandNum >= 1, "No island found!");
// no more than one islands
if (islandNum == 1)
{
return(null);
}
var result = new List <ExploderMesh>(islands.Count);
foreach (var island in islandsIdx)
{
var cutterMesh = new ExploderMesh();
var triCount = island.Count;
var m = cutterMesh;
var tt = new List <int>(triCount);
var vs = new List <Vector3>(triCount);
var ns = new List <Vector3>(triCount);
var us = new List <Vector2>(triCount);
var cs = new List <Color32>(triCount);
var ts = new List <Vector4>(triCount);
var triCache = new Dictionary <int, int>(trianglesNum);
var centroid = Vector3.zero;
var centroidCounter = 0;
var triCounter = 0;
foreach (var i in island)
{
var tri = triangles[i];
var id = 0;
if (triCache.TryGetValue(tri, out id))
{
tt.Add(id);
continue;
}
tt.Add(triCounter);
triCache.Add(tri, triCounter);
triCounter++;
centroid += vertices[tri];
centroidCounter++;
vs.Add(vertices[tri]);
us.Add(uvs[tri]);
if (useNormals)
{
ns.Add(normals[tri]);
}
if (useVertexColors)
{
cs.Add(colors[tri]);
}
if (useMeshTangents)
{
ts.Add(tangents[tri]);
}
}
m.vertices = vs.ToArray();
m.uv = us.ToArray();
if (useNormals)
{
m.normals = ns.ToArray();
}
if (useVertexColors)
{
m.colors32 = cs.ToArray();
}
if (useMeshTangents)
{
m.tangents = ts.ToArray();
}
m.triangles = tt.ToArray();
cutterMesh.centroid = centroid / centroidCounter;
result.Add(cutterMesh);
}
return(result);
}
public void AddTriangle(int triangleID, int id0, int id1, Vector3 v0, Vector3 v1)
{
#if PROFILING
MeasureIt.Begin("AddTriangle");
#endif
// we need to compute position hash to make sure we find all (duplicated) vertices with different edges
int hash0, hash1;
lsHash.Hash(v0, v1, out hash0, out hash1);
// filter out points with similar positions
if (hash0 == hash1)
{
#if PROFILING
MeasureIt.End("AddTriangle");
#endif
return;
}
MidPoint midPoint;
if (midPoints.TryGetValue(hash0, out midPoint))
{
if (midPoint.idNext == Int32.MaxValue && midPoint.idPrev != hash1)
{
midPoint.idNext = hash1;
}
else if (midPoint.idPrev == Int32.MaxValue && midPoint.idNext != hash1)
{
midPoint.idPrev = hash1;
}
midPoints[hash0] = midPoint;
}
else
{
midPoints.Add(hash0, new MidPoint {
id = hash0, vertexId = id0, idNext = hash1, idPrev = Int32.MaxValue /*, position = v0*/
});
}
if (midPoints.TryGetValue(hash1, out midPoint))
{
if (midPoint.idNext == Int32.MaxValue && midPoint.idPrev != hash0)
{
midPoint.idNext = hash0;
}
else if (midPoint.idPrev == Int32.MaxValue && midPoint.idNext != hash0)
{
midPoint.idPrev = hash0;
}
midPoints[hash1] = midPoint;
}
else
{
midPoints.Add(hash1, new MidPoint {
id = hash1, vertexId = id1, idPrev = hash0, idNext = Int32.MaxValue /*, position = v1*/
});
}
MidPointsCount = midPoints.Count;
#if PROFILING
MeasureIt.End("AddTriangle");
#endif
}
