public static void FindMeshBorder(List <Vector2> vertes, List <int> indices, out List <List <Vector2> > borderLst)
{
int count = indices.Count / 3;
Dictionary <string, EdgeObject> mEdgeDict = new Dictionary <string, EdgeObject>();
for (int i = 0; i < count; ++i)
{
int st = i * 3;
for (int j = st; j < (st + 3); ++j)
{
int next = j + 1;
if (next == (st + 3))
{
next = st;
}
Vector2i edge = Vector2i.GetVector2i(indices[j], indices[next]);
string str1 = edge.GetString();
if (!mEdgeDict.ContainsKey(str1))
{
mEdgeDict.Add(str1, new EdgeObject(edge));
}
else
{
mEdgeDict[str1].CountPlus();
}
}
}
List <EdgeObject> oneList = mEdgeDict.Values.ToList().FindAll(t => { return(t.mCount == 1); });
GroupClosest <EdgeObject> group = new GroupClosest <EdgeObject>(oneList);
List <List <EdgeObject> > results = group.Group();
borderLst = new List <List <Vector2> >();
foreach (List <EdgeObject> res in results)
{
List <Vector2> tmp = new List <Vector2>();
EdgeObject obj0 = res[0];
int first = obj0.mEdge[0];
int last = obj0.mEdge[1];
tmp.Add(vertes[first]);
tmp.Add(vertes[last]);
res.RemoveAt(0);
while (res.Count > 0)
{
int index1 = res.FindIndex(o => { return(o.Include(last)); });
if (index1 == -1)
{
tmp.Clear();
break;
}
EdgeObject obj = res[index1];
int index = obj.IndexOf(last);
index = 1 - index;
last = obj.mEdge[index];
tmp.Add(vertes[last]);
res.RemoveAt(index1);
}
if (tmp.Count > 2)
{
tmp.RemoveAt(tmp.Count - 1);
borderLst.Add(tmp);
}
}
}
public EdgeObject(int i, int j)
{
mEdge = Vector2i.GetVector2i(i, j);
mCount = 1;
}
public void SharedFace(int f1, int f2)
{
mSharedTriangles = Vector2i.GetVector2i(f1, f2);
}
public static List <Vector2i> Scan(List <Vector2i> poly)
{
List <Vector2i> results = new List <Vector2i>();
Vector2i max = new Vector2i(int.MinValue, int.MinValue);
Vector2i min = new Vector2i(int.MaxValue, int.MaxValue);
foreach (Vector2i v in poly)
{
max = Vector2i.Max(v, max);
min = Vector2i.Min(v, min);
}
List <Vector2i> trans = poly.Select(t => { return(t - min); }).ToList();
int height = max[1] - min[1];
List <ScanEdge> scanLines = new List <ScanEdge>();
int count = trans.Count;
int count1 = count - 1;
for (int i = 0; i < count; ++i)
{
Vector2i ps = trans[i];
int post = (i + 1) % count;
Vector2i pe = trans[post];
if (ps[1] == pe[1]) // 水平 去掉
{
Vector2i hori = Vector2i.GetVector2i(ps[0], pe[0]);
for (int hi = hori[0]; hi <= hori[1]; ++hi)
{
results.Add(new Vector2i(hi, ps[1]));
}
continue;
}
int pre = (i + count1) % count;
Vector2i pss = trans[pre];
int ppost = (post + 1) % count;
Vector2i pee = trans[ppost];
double dx = (ps[0] - pe[0]) * 1.0f / (ps[1] - pe[1]);
bool yiG0 = ps[1] < pe[1];
double startX = yiG0 ? ps[0] : pe[0];
int ymin = yiG0 ? ps[1] : pe[1];
int ymax = yiG0 ? pe[1] : ps[1];
if (pe[1] > ps[1])
{
if (pee[1] >= pe[1])
{
ymax -= 1;
}
}
else
{
if (pss[1] >= ps[1])
{
ymax -= 1;
}
}
ScanEdge ep = new ScanEdge();
ep.mMinY = ymin;
ep.mMaxY = ymax;
ep.mStartX = startX;
ep.mDx = dx;
scanLines.Add(ep);
}
for (int i = 0; i < height; ++i)
{
List <ScanEdge> tmp = scanLines.FindAll(delegate(ScanEdge line) { return(line.Include(i)); });
tmp.Sort((e1, e2) =>
{
//此处可以不考虑 斜率。 x相等时，不用考虑谁在前谁在后
return(e1.mStartX.CompareTo(e2.mStartX));
});
if (tmp.Count % 2 != 0)
{
throw new Exception("必须是偶数");
}
for (int idx = 0; idx < tmp.Count; idx += 2)
{
int next = idx + 1;
int x1 = (int)tmp[idx].mStartX;
int x2 = (int)tmp[next].mStartX;
if (x1 > x2)
{
continue;
}
for (int xi = x1; xi <= x2; ++xi)
{
results.Add(new Vector2i(xi, i));
}
tmp[idx].Increase();
tmp[next].Increase();
}
scanLines.RemoveAll((t) => t.mMaxY == i);
}
results = results.Select(t => { return(t + min); }).ToList();
return(results);
}
public SharedEdge(int index, int i, int j, int other)
{
mEdgeVertexIndex = Vector2i.GetVector2i(i, j);
mFaceIndex = index;
mOtherVertex = other;
}
