public void RebuildBounding(QuadTreeNode node)
{
Vector3 min = new Vector3(float.MaxValue, float.MaxValue, float.MaxValue);
Vector3 max = new Vector3(float.MinValue, float.MinValue, float.MinValue);
Type type = node.GetType();
if (type == typeof(QuadTree))
{
QuadTree tree = (QuadTree)node;
if (tree.UpperLeft != null)
{
RebuildBounding(tree.UpperLeft);
min = Vector3.Min(min, tree.UpperLeft.BoundingBox.Min);
max = Vector3.Max(max, tree.UpperLeft.BoundingBox.Max);
}
if (tree.UpperRight != null)
{
RebuildBounding(tree.UpperRight);
min = Vector3.Min(min, tree.UpperRight.BoundingBox.Min);
max = Vector3.Max(max, tree.UpperRight.BoundingBox.Max);
}
if (tree.LowerLeft != null)
{
RebuildBounding(tree.LowerLeft);
min = Vector3.Min(min, tree.LowerLeft.BoundingBox.Min);
max = Vector3.Max(max, tree.LowerLeft.BoundingBox.Max);
}
if (tree.LowerRight != null)
{
RebuildBounding(tree.LowerRight);
min = Vector3.Min(min, tree.LowerRight.BoundingBox.Min);
max = Vector3.Max(max, tree.LowerRight.BoundingBox.Max);
}
}
else if (type == typeof(LandscapeBlock))
{
LandscapeBlock block = (LandscapeBlock)node;
min = Vector3.Min(min, block.BoundingBox.Min);
max = Vector3.Max(max, block.BoundingBox.Max);
}
node.BoundingBox = new BoundingBox(min, max);
}
public void BuildLandscapeBlocks(Texture2D heightmap)
{
// Calculate how many blocks we should make based off total Width / desired size of each block
numBlocksX = Width / BlockSize;
numBlocksZ = Height / BlockSize;
Blocks = new LandscapeBlock[numBlocksX][];
// create blocks
for (int x = 0; x < numBlocksX; x++)
{
Blocks[x] = new LandscapeBlock[numBlocksZ];
for (int z = 0; z < numBlocksZ; z++)
{
LandscapeBlock block = new LandscapeBlock(Game, Width, Height, x * BlockSize, z * BlockSize);
block.Position = new Vector2(x * BlockSize, z * BlockSize);
block.Width = BlockSize;
block.Height = BlockSize;
block.HeightColorData = new Color[(BlockSize + 1) * (BlockSize + 1)];
block.MaxHeight = MaxHeight;
block.Smoothness = Smoothness;
block.Camera = Camera;
// Height map data provided
if (heightmap != null)
{
heightmap.GetData(0,
new Rectangle((int)block.Position.X, (int)block.Position.Y, (BlockSize + 1), (BlockSize + 1)),
block.HeightColorData, 0, (BlockSize + 1) * (BlockSize + 1));
}
block.Initialize();
Blocks[x][z] = block;
}
}
FindNeighborBlocks();
Trunk = BuildTreeNode(0, 0, numBlocksX, numBlocksZ) as QuadTree;
}
public int DrawTreeNode(BoundingFrustum frustum, QuadTreeNode node, GameTime gameTime)
{
int totalTriangles = 0;
if (node != null && node.Visible != true)
{
return(totalTriangles);
}
if (node is QuadTree)
{
QuadTree tree = (QuadTree)node;
if (!tree.BoundingBox.Intersects(frustum))
{
return(0);
}
if (tree.UpperLeft != null)
{
if (tree.UpperLeft.BoundingBox.Intersects(frustum))
{
totalTriangles += DrawTreeNode(frustum, tree.UpperLeft, gameTime);
}
}
if (tree.UpperRight != null)
{
if (tree.UpperRight.BoundingBox.Intersects(frustum))
{
totalTriangles += DrawTreeNode(frustum, tree.UpperRight, gameTime);
}
}
if (tree.LowerLeft != null)
{
if (tree.LowerLeft.BoundingBox.Intersects(frustum))
{
totalTriangles += DrawTreeNode(frustum, tree.LowerLeft, gameTime);
}
}
if (tree.LowerRight != null)
{
if (tree.LowerRight.BoundingBox.Intersects(frustum))
{
totalTriangles += DrawTreeNode(frustum, tree.LowerRight, gameTime);
}
}
}
else if (node is LandscapeBlock)
{
LandscapeBlock block = (LandscapeBlock)node;
{
if (block.Visible)
{
if (block.BoundingBox.Intersects(frustum))
{
totalTriangles += block.DrawBlock(gameTime);
}
}
}
}
return(totalTriangles);
}
public void UpdateTreeNode(BoundingFrustum frustum, QuadTreeNode node, bool skipFrustumCheck, GameTime gameTime)
{
node.Visible = false;
if (skipFrustumCheck != true)
{
ContainmentType containment = frustum.Contains(node.BoundingBox);
if (containment == ContainmentType.Disjoint)
{
return;
}
// if the entire node is contained within, then assume all children are as well
if (containment == ContainmentType.Contains)
{
skipFrustumCheck = true;
}
}
node.Visible = true;
Type type = node.GetType();
if (type == typeof(QuadTree))
{
QuadTree tree = (QuadTree)node;
if (tree.UpperLeft != null)
{
UpdateTreeNode(frustum, tree.UpperLeft, skipFrustumCheck, gameTime);
}
if (tree.UpperRight != null)
{
UpdateTreeNode(frustum, tree.UpperRight, skipFrustumCheck, gameTime);
}
if (tree.LowerLeft != null)
{
UpdateTreeNode(frustum, tree.LowerLeft, skipFrustumCheck, gameTime);
}
if (tree.LowerRight != null)
{
UpdateTreeNode(frustum, tree.LowerRight, skipFrustumCheck, gameTime);
}
}
else if (type == typeof(LandscapeBlock))
{
LandscapeBlock block = (LandscapeBlock)node;
{
if (block.BoundingBox.Intersects(frustum))
{
block.Visible = true;
block.Update(gameTime);
}
else
{
block.Visible = false;
}
}
}
}
