public void RecursRender(List<Vertex> vBuf, TriTreeNode tri, int leftX, int leftY, int rightX, int rightY, int apexX, int apexY)
{
if (tri.LeftChild != 0)
{
int centerX = (leftX + rightX) >> 1; // Compute X coordinate of center of Hypotenuse
int centerY = (leftY + rightY) >> 1; // Compute Y coord...
RecursRender(vBuf, Land[tri.LeftChild], apexX, apexY, leftX, leftY, centerX, centerY);
RecursRender(vBuf, Land[tri.RightChild], rightX, rightY, apexX, apexY, centerX, centerY);
return;
}
float leftH = Land.FetchFunction(leftX, leftY);
float rightH = Land.FetchFunction(rightX, rightY);
float apexH = Land.FetchFunction(apexX, apexY);
vBuf.Add(CreateVertex(leftX, leftY, leftH));
vBuf.Add(CreateVertex(rightX, rightY, rightH));
vBuf.Add(CreateVertex(apexX, apexY, apexH));
}
public void RecursTessellate(TriTreeNode tri, int leftX, int leftY, int rightX, int rightY, int apexX, int apexY)
{
int centerX = (leftX + rightX) >> 1; // Compute X coordinate of center of Hypotenuse
int centerY = (leftY + rightY) >> 1; // Compute Y coord...
bool doSplit = Land.SplitFunction(leftX, leftY, rightX, rightY, apexX, apexY);
if( doSplit)
{
//Console.WriteLine("split: " + tri);
Split(tri); // Split this triangle.
if (tri.LeftChild != 0 && // If this triangle was split, try to split it's children as well.
((Math.Abs(leftX - rightX) >= 2) || (Math.Abs(leftY - rightY) >= 2))) // Tessellate all the way down to one vertex per height field entry
{
RecursTessellate(Land[tri.LeftChild], apexX, apexY, leftX, leftY, centerX, centerY);
RecursTessellate(Land[tri.RightChild], rightX, rightY, apexX, apexY, centerX, centerY);
}
}
}
void CheckTriNeighbours(TriTreeNode tri)
{
if (tri.BaseNeighbor == tri.Self)
throw new Exception("TriTreeNode is its own BaseNeighbour. " + tri);
if (tri.LeftNeighbor == tri.Self)
throw new Exception("TriTreeNode is its own LeftNeighbor. " + tri);
if (tri.RightNeighbor == tri.Self)
throw new Exception("TriTreeNode is its own RightNeighbor. " + tri);
}
void CheckTriChildren(TriTreeNode tri)
{
if (tri.LeftChild == 0)
return;
if (tri.LeftChild <= tri.Self)
throw new Exception("TriTreeNode is younger than LeftChild. " + tri);
if (tri.RightChild <= tri.Self)
throw new Exception("TriTreeNode is younger than RightChild. " + tri);
}
private static bool IsLeafNode(TriTreeNode tri)
{
if (tri.Self == 0)
throw new Exception("Used invalid TriTreeNode. " + tri);
if (tri.LeftChild == 0 || tri.RightChild == 0)
{
if (tri.RightChild != tri.LeftChild)
throw new Exception("TriTreeNode has only one valid child. " + tri);
return true;
}
return false;
}
public void Split(TriTreeNode tri)
{
CheckTriChildren(tri);
if (!IsLeafNode(tri))
return;
if (tri.BaseNeighbor != 0 && (Land[tri.BaseNeighbor].BaseNeighbor != tri.Self))
Split(Land[tri.BaseNeighbor]);
tri.LeftChild = Land.GetNextNode();
tri.RightChild = Land.GetNextNode();
TriTreeNode lc = Land[tri.LeftChild];
TriTreeNode rc = Land[tri.RightChild];
// If creation failed, just exit.
if (rc.Self == 0 || lc.Self == 0)
{
tri.LeftChild = 0;
tri.RightChild = 0;
return;
}
CheckTriChildren(tri);
// Fill in the information we can get from the parent (neighbor pointers)
lc.BaseNeighbor = tri.LeftNeighbor;
lc.LeftNeighbor = tri.RightChild;
rc.BaseNeighbor = tri.RightNeighbor;
rc.RightNeighbor = tri.LeftChild;
// Link our Left Neighbor to the new children
if (tri.LeftNeighbor != 0)
{
TriTreeNode ln = Land[tri.LeftNeighbor];
if (ln.BaseNeighbor == tri.Self)
ln.BaseNeighbor = tri.LeftChild;
else if (ln.LeftNeighbor == tri.Self)
ln.LeftNeighbor = tri.LeftChild;
else if (ln.RightNeighbor == tri.Self)
ln.RightNeighbor = tri.LeftChild;
else
{ }// throw new Exception("Illegal Left Neighbour");// Illegal Left Neighbor!
// Not throwing exception, since this is actually legal if a patch is invisible.
}
// Link our Right Neighbor to the new children
if (tri.RightNeighbor != 0)
{
TriTreeNode rn = Land[tri.RightNeighbor];
if (rn.BaseNeighbor == tri.Self)
rn.BaseNeighbor = tri.RightChild;
else if (rn.RightNeighbor == tri.Self)
rn.RightNeighbor = tri.RightChild;
else if (rn.LeftNeighbor == tri.Self)
rn.LeftNeighbor = tri.RightChild;
else
{ }// throw new Exception("Illegal Right Neighbour");// Illegal Right Neighbor!
}
// Link our Base Neighbor to the new children
if (tri.BaseNeighbor != 0)
{
TriTreeNode bn = Land[tri.BaseNeighbor];
if (bn.LeftChild != 0)
{
Land[bn.LeftChild].RightNeighbor = tri.RightChild;
Land[bn.RightChild].LeftNeighbor = tri.LeftChild;
lc.RightNeighbor = bn.RightChild;
rc.LeftNeighbor = bn.LeftChild;
}
else
Split(bn); // Base Neighbor (in a diamond with us) was not split yet, so do that now.
}
else
{
// An edge triangle, trivial case.
lc.RightNeighbor = 0;
rc.LeftNeighbor = 0;
}
IsLeafNode(tri);
CheckTriNeighbours(tri);
}
public void Init()
{
MaxTris = NUM_PATCHES_PER_SIDE * NUM_PATCHES_PER_SIDE * 4;
nodeList = new TriTreeNode[MaxTris];
for (int i = 0; i < nodeList.Length; i++)
{
nodeList[i] = new TriTreeNode();
nodeList[i].Self = i;
}
Patches = new Patch[NUM_PATCHES_PER_SIDE, NUM_PATCHES_PER_SIDE];
for(int y = 0; y < NUM_PATCHES_PER_SIDE; y++)
for (int x = 0; x < NUM_PATCHES_PER_SIDE; x++)
{
Patch p = new Patch(this);
p.Init(x*PATCH_SIZE, y * PATCH_SIZE, x * PATCH_SIZE, y * PATCH_SIZE);
Patches[y, x] = p;
}
this.Reset();
this.RecreateVertices();
}
