private void Collapse(QuadtreeNode <T> node)
{
if (node.IsLeaf())
{
if (node.parent != null && node.IsEmpty())
{
Collapse(node.parent);
}
}
else
{
bool empty = true;
for (int i = 0; i < 4 && empty; i++)
{
if (!node.children[i].IsLeaf() || !node.children[i].IsEmpty())
{
empty = false;
}
}
if (empty)
{
node.children = new QuadtreeNode <T> [4];
if (node.parent != null)
{
Collapse(node.parent);
}
}
}
}
public void TectBuildTree_ZoomLevels_2()
{
List <DataRow> data = new List <DataRow>();
double val = 0;
for (int i = 0; i < 100; i++)
{
val += i > 0 ? 1.0 / i : 0;
data.Add(new DataRow()
{
Argument = val, Value = 1
});
}
QuadtreeNode startNode = QuardtreeBuilder.BuildTree(data, 10);
var wholeRange = QuardtreeBuilder.GetWholeRange(startNode);
int counter = 0;
startNode.VisitNodes(wholeRange, 10, node => { counter++; });
Assert.AreEqual(1, counter);
counter = 0;
startNode.VisitNodes(wholeRange, 1, node => { counter++; });
Assert.AreEqual(100, counter);
counter = 0;
startNode.VisitNodes(wholeRange, 2, node => { counter++; });
Assert.AreEqual(3, counter);
}
private void Remove(QuadtreeNode <T> node, T value)
{
if (node == null)
{
return;
}
if (!node.Intersects(value.Collider))
{
return;
}
if (!node.IsLeaf())
{
foreach (QuadtreeNode <T> child in node.children)
{
Remove(child, value);
}
}
else
{
if (node.Remove(value))
{
if (node.IsEmpty())
{
Collapse(node);
}
}
}
}
/// <summary>
/// Quick (O(n log n)) and accurate collision detection
/// </summary>
/// <param name="labels"></param>
public static void QuickAccurateCollisionDetectionMethod(List<BaseLabel> labels)
{
// find minimum / maximum coordinates
double minX = double.MaxValue;
double maxX = double.MinValue;
double minY = double.MaxValue;
double maxY = double.MinValue;
foreach (BaseLabel l in labels)
{
ProperBox box = new ProperBox(l.Box);
if (box.Left < minX) minX = box.Left;
if (box.Right > maxX) maxX = box.Right;
if (box.Bottom > maxY) maxY = box.Bottom;
if (box.Top < minY) minY = box.Top;
}
// sort by area (highest priority first, followed by low area to maximize the amount of labels displayed)
var sortedLabels = labels.OrderByDescending(label => label.Priority).ThenBy(label => label.Box.Width * label.Box.Height);
// make visible if it does not collide with other labels. Uses a quadtree and is therefore fast O(n log n)
QuadtreeNode<ProperBox> quadTree = new QuadtreeNode<ProperBox>(minX, maxX, minY, maxY, new LabelBoxContainmentChecker(), 0, 10);
foreach (BaseLabel l in sortedLabels)
{
if (!l.Show) continue;
if (quadTree.CollidesWithAny(new ProperBox(l.Box)))
{
l.Show = false;
}
else
{
ProperBox box = new ProperBox(l.Box);
quadTree.Insert(box);
}
}
}
public void Subdivide(int depth = 0)
{
subnodes = new QuadtreeNode <TType> [4];
for (int i = 0; i < subnodes.Length; i++)
{
Vector2 newPos = position;
if ((i & 2) == 2)
{
newPos.y -= size * 0.25f;
}
else
{
newPos.y += size * 0.25f;
}
if ((i & 1) == 1)
{
newPos.x += size * 0.25f;
}
else
{
newPos.x -= size * 0.25f;
}
subnodes[i] = new QuadtreeNode <TType>(newPos, size * 0.5f);
if (depth > 0)
{
subnodes[i].Subdivide(depth - 1);
}
}
}
public void accumulate(QuadtreeNode quad, double x0, double y0, double x1, double y1)
{
double x = 0, y = 0, strength = 0, c;
QuadtreeNode q;
//对于内部节点，积累来自子象限的力。
if (quad.children != null)
{
for (int i = 0; i < 4; i++)
{
if (quad.children[i] != null)
{
q = quad.children[i];
c = q.value;
strength += c;
x += c * q.x;
y += c * q.y;
}
}
quad.x = x / strength;
quad.y = y / strength;
}
//对叶结点，积累来自重合象限的力
else
{
q = quad;
q.x = q.data.x;
q.y = q.data.y;
strength += strengthsManyBody[q.data.index];
}
quad.value = strength;
}
public QuadtreeNode(int size, Vector2F position, QuadtreeNode <T> parent)
{
this.size = size;
this.position = position;
this.parent = parent;
this.children = new QuadtreeNode <T> [4];
}
/// <summary>
/// Inserts a value into the region.
/// </summary>
/// <param name="x">
/// The X component of the value's position.
/// </param>
/// <param name="y">
/// The y component of the value's position.
/// </param>
/// <param name="value">
/// The value to insert.
/// </param>
/// <returns>
/// true if the value was inserted into the region;
/// false if the value's position was outside the region.
/// </returns>
public bool Insert(float x, float y, T value)
{
var position = new Vector2(x, y);
var node = new QuadtreeNode(position, value);
return(this.Insert(node));
}
public bool IsInsideCircle(Vector2 position, float radius, QuadtreeNode <TType> node)
{
Vector2 difference = node.Position - position;
difference.x = Math.Max(0, Mathf.Abs(difference.x) - node.Size / 2);
difference.y = Math.Max(0, Mathf.Abs(difference.y) - node.Size / 2);
return(difference.magnitude < radius);
}
public Quadtree(int size)
{
if (!size.IsPowerOfTwo())
{
throw new System.ArgumentException("Size must be power of two!");
}
root = new QuadtreeNode <T>(new Rect(0, 0, size, size));
}
private void Split(QuadtreeNode <T> node)
{
int childSize = node.Size / 2;
for (int i = 0; i < 4; i++)
{
Vector2F childPosition = node.Position + OFFSET[i] * childSize;
node.children[i] = new QuadtreeNode <T>(childSize, childPosition, node);
}
}
public ChildNodes(QuadtreeNode <T> parentNode)
{
_nodes = new QuadtreeNode <T>[4]
{
new QuadtreeNode <T>(parentNode._rect.GetFirstQuadrant(), parentNode._maxObjects),
new QuadtreeNode <T>(parentNode._rect.GetSecondQuadrant(), parentNode._maxObjects),
new QuadtreeNode <T>(parentNode._rect.GetThirdQuadrant(), parentNode._maxObjects),
new QuadtreeNode <T>(parentNode._rect.GetFourthQuadrant(), parentNode._maxObjects),
};
}
/// <summary>
/// Builds a terrain quadtree from the heightmap.
/// </summary>
/// <param name="heightMap">The heightmap of the terrain.</param>
protected QuadtreeNode BuildQuadtree(Texture2D heightMap)
{
QuadtreeNode root = new QuadtreeNode(new BoundingBox(Vector3.Zero, new Vector3(heightMap.Width * tileSize, 0.0f, heightMap.Height * tileSize)));
Color[] heightMapColors = new Color[heightMap.Width * heightMap.Height];
heightMap.GetData(heightMapColors);
BuildQuadtree(heightMapColors, root);
return(root);
}
/// <summary>
/// Draws the terrain with with the custom effect.
/// </summary>
/// <param name="root">The root node of the quadtree.</param>
protected void DrawTerrain(QuadtreeNode root)
{
terrainEffect.Parameters["WorldViewProjection"].SetValue(Matrix.Identity * view * projection);
terrainEffect.Parameters["LightDirection"].SetValue(lightDirection);
terrainEffect.Parameters["AmbientIntensity"].SetValue(ambientIntensity);
foreach (EffectPass pass in terrainEffect.CurrentTechnique.Passes)
{
pass.Apply();
DrawQuadtree(root);
}
}
private void Subdivide()
{
float xo = aabb.extents.x * 0.5f;
float yo = aabb.extents.y * 0.5f;
northeast = new QuadtreeNode(new AABB(new Vector2(aabb.center.x - xo, aabb.center.y + yo), aabb.extents), capacity);
northwest = new QuadtreeNode(new AABB(new Vector2(aabb.center.x + xo, aabb.center.y + yo), aabb.extents), capacity);
southeast = new QuadtreeNode(new AABB(new Vector2(aabb.center.x - xo, aabb.center.y - yo), aabb.extents), capacity);
southwest = new QuadtreeNode(new AABB(new Vector2(aabb.center.x + xo, aabb.center.y - yo), aabb.extents), capacity);
subdivided = true;
}
private void DrawNode(QuadtreeNode <int> node, int nodeDepth = 0)
{
if (!node.IsLeaf())
{
foreach (var subNode in node.Nodes)
{
DrawNode(subNode, nodeDepth + 1);
}
}
Gizmos.color = Color.Lerp(minColor, maxColor, nodeDepth / (float)depth);
Gizmos.DrawWireCube(node.Position, new Vector3(1, 1, 0.1f) * node.Size);
}
/// <summary>
/// 查询初始化
/// </summary>
/// <param name="node">初始节点</param>
/// <param name="x0"></param>
/// <param name="y0"></param>
/// <param name="x1"></param>
/// <param name="y1"></param>
/// <returns></returns>
QuadtreeVisit quad(QuadtreeNode node, double x0, double y0, double x1, double y1)
{
double x00 = x0, y00 = y0, x10 = x1, y10 = y1;
QuadtreeVisit visit = new QuadtreeVisit
{
node = node,
x0 = x0,
x1 = x1,
y0 = y0,
y1 = y1
};
return(visit);
}
/// <summary>
/// Inserts a node into the region.
/// </summary>
/// <param name="node">
/// The node to insert.
/// </param>
/// <returns>
/// true if the node was inserted into the region;
/// false if the position of the node was outside the region.
/// </returns>
private bool Insert(QuadtreeNode node)
{
if (!this.boundaries.Contains(node.Position))
{
return(false);
}
if (this.children != null)
{
Quadtree <T> child;
if (node.Position.y < this.children[2].boundaries.yMin)
{
if (node.Position.x < this.children[1].boundaries.xMin)
{
child = this.children[0];
}
else
{
child = this.children[1];
}
}
else
{
if (node.Position.x < this.children[1].boundaries.xMin)
{
child = this.children[2];
}
else
{
child = this.children[3];
}
}
if (child.Insert(node))
{
this.Count++;
return(true);
}
}
if (this.nodes.Count < this.nodeCapacity)
{
this.nodes.Add(node);
this.Count++;
return(true);
}
this.Subdivide();
return(this.Insert(node));
}
private QuadtreeNode <TType>[] BuildQuadtree(Vector2 position, float size, int depth)
{
int length = 0;
for (int i = 0; i <= depth; ++i)
{
length += (int)Mathf.Pow(4, i);
}
var quadtree = new QuadtreeNode <TType> [length];
quadtree[0] = new QuadtreeNode <TType>(position, size, 0);
BuildQuadtreeRecursively(quadtree, 0);
return(quadtree);
}
private void Draw(QuadtreeNode <T> node)
{
if (node == null)
{
return;
}
Gizmos.color = (node.Objects != null) ? Color.red : Color.blue;
Vector3 pos = node.Center.ToVector3();
float size = node.Size;
Gizmos.DrawWireCube(pos, new Vector3(size, 1, size));
for (int i = 0; i < 4; i++)
{
Draw(node.children[i]);
}
}
/// <summary>
/// Recursively subdivides the terrain quadtree.
/// </summary>
/// <param name="depth">The current zero-based depth of the algorithm.</param>
/// <param name="heightMapColors">The array of heightmap colors.</param>
/// <param name="node">The node of the quadtree that will be subdivided.</param>
protected void BuildQuadtree(Color[] heightMapColors, QuadtreeNode node, int depth = 0)
{
Vector3 min = node.boundingBox.Min;
Vector3 max = node.boundingBox.Max;
Vector3 middle = (min + max) / 2;
BoundingBox topLeft = new BoundingBox(min, middle);
BoundingBox topRight = new BoundingBox(new Vector3(middle.X, 0, min.Z), new Vector3(max.X, 0, middle.Z));
BoundingBox bottomLeft = new BoundingBox(new Vector3(min.X, 0, middle.Z), new Vector3(middle.X, 0, max.Z));
BoundingBox bottomRight = new BoundingBox(middle, max);
if (depth < 5)
{
BuildQuadtree(heightMapColors, node.topLeft = new QuadtreeNode(topLeft), depth + 1);
BuildQuadtree(heightMapColors, node.topRight = new QuadtreeNode(topRight), depth + 1);
BuildQuadtree(heightMapColors, node.bottomLeft = new QuadtreeNode(bottomLeft), depth + 1);
BuildQuadtree(heightMapColors, node.bottomRight = new QuadtreeNode(bottomRight), depth + 1);
}
else
{
node.topLeft = new QuadtreeLeaf(topLeft, heightMapColors, graphics.GraphicsDevice);
node.topRight = new QuadtreeLeaf(topRight, heightMapColors, graphics.GraphicsDevice);
node.bottomLeft = new QuadtreeLeaf(bottomLeft, heightMapColors, graphics.GraphicsDevice);
node.bottomRight = new QuadtreeLeaf(bottomRight, heightMapColors, graphics.GraphicsDevice);
}
float[] mins = new float[4] {
node.topLeft.boundingBox.Min.Y,
node.topRight.boundingBox.Min.Y,
node.bottomLeft.boundingBox.Min.Y,
node.bottomRight.boundingBox.Min.Y
};
Array.Sort(mins);
float[] maxes = new float[4] {
node.topLeft.boundingBox.Max.Y,
node.topRight.boundingBox.Max.Y,
node.bottomLeft.boundingBox.Max.Y,
node.bottomRight.boundingBox.Max.Y
};
Array.Sort(maxes);
node.boundingBox.Min.Y = MathHelper.Min(100.0f, mins[0]);
node.boundingBox.Max.Y = MathHelper.Max(node.boundingBox.Max.Y, maxes[3]);
}
private void FindCollisions(QuadtreeNode <T> node, HashSet <Manifold> collisionSet)
{
if (node == null)
{
return;
}
if (node.IsLeaf())
{
node.GetCollisions(collisionSet);
}
else
{
foreach (QuadtreeNode <T> child in node.children)
{
FindCollisions(child, collisionSet);
}
}
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
spriteBatch = new SpriteBatch(GraphicsDevice);
hudfont = Content.Load <SpriteFont>("hudFont");
heightMap = Content.Load <Texture2D>("heightMap");
grass = Content.Load <Texture2D>("grass");
rock = Content.Load <Texture2D>("rock");
sand = Content.Load <Texture2D>("sand");
terrainEffect = Content.Load <Effect>("terrainEffect");
terrainEffect.Parameters["MapWidth"].SetValue(heightMap.Width);
terrainEffect.Parameters["MapHeight"].SetValue(heightMap.Height);
terrainEffect.Parameters["TileSize"].SetValue(tileSize);
terrainEffect.Parameters["MaxHeight"].SetValue(100.0f);
terrainEffect.Parameters["WaterHeight"].SetValue(10.0f);
terrainEffect.Parameters["HeightMap"].SetValue(heightMap);
terrainEffect.Parameters["Texture0"].SetValue(grass);
terrainEffect.Parameters["Texture1"].SetValue(rock);
terrainEffect.Parameters["Texture2"].SetValue(sand);
quadtreeRoot = BuildQuadtree(heightMap);
water = Content.Load <Texture2D>("water");
waterNormalMap = Content.Load <Texture2D>("waterNormalMap");
waterEffect = Content.Load <Effect>("waterEffect");
waterEffect.Parameters["ColorMap"].SetValue(water);
waterEffect.Parameters["NormalMap"].SetValue(waterNormalMap);
VertexPositionTexture[] waterVertices = new VertexPositionTexture[4];
waterVertices[0] = new VertexPositionTexture(new Vector3(-8000, 10, -8000), new Vector2(0, 0));
waterVertices[1] = new VertexPositionTexture(new Vector3(-8000, 10, 8000), new Vector2(0, 16000 / 2));
waterVertices[2] = new VertexPositionTexture(new Vector3(8000, 10, -8000), new Vector2(16000 / 2, 0));
waterVertices[3] = new VertexPositionTexture(new Vector3(8000, 10, 8000), new Vector2(16000 / 2, 16000 / 2));
waterVertexBuffer = new VertexBuffer(
GraphicsDevice, typeof(VertexPositionTexture), waterVertices.Length, BufferUsage.WriteOnly);
waterVertexBuffer.SetData <VertexPositionTexture>(waterVertices);
}
public void TectBuildTree_Simple()
{
List <DataRow> data = new List <DataRow>();
data.Add(new DataRow()
{
Argument = 0.5, Value = 0.5,
});
data.Add(new DataRow()
{
Argument = 0, Value = 0,
});
data.Add(new DataRow()
{
Argument = 1, Value = 0,
});
data.Add(new DataRow()
{
Argument = 0, Value = 1,
});
data.Add(new DataRow()
{
Argument = 1, Value = 1,
});
QuadtreeNode startNode = QuardtreeBuilder.BuildTree(data);
Assert.AreEqual(startNode.X, 0.5);
Assert.AreEqual(startNode.Y, 0.5);
Assert.AreEqual(startNode.NE.X, 1);
Assert.AreEqual(startNode.NE.Y, 1);
Assert.AreEqual(startNode.NW.X, 0);
Assert.AreEqual(startNode.NW.Y, 1);
Assert.AreEqual(startNode.SW.X, 0);
Assert.AreEqual(startNode.SW.Y, 0);
Assert.AreEqual(startNode.SE.X, 1);
Assert.AreEqual(startNode.SE.Y, 0);
}
public void Subdivide(Vector2 targetPosition, TType type, int depth = 0)
{
var subdivIndex = GetIndexOfPosition(targetPosition, position);
if (subNodes == null)
{
subNodes = new QuadtreeNode <TType> [4];
for (int i = 0; i < subNodes.Length; i++)
{
Vector2 newPos = position;
if ((i & 2) == 2)
{
newPos.y -= size * 0.25f;
}
else
{
newPos.y += size * 0.25f;
}
if ((i & 1) == 1)
{
newPos.x += size * 0.25f;
}
else
{
newPos.x -= size * 0.25f;
}
subNodes[i] = new QuadtreeNode <TType>(newPos, size * 0.5f);
}
}
if (depth > 0)
{
Debug.Log("Subdivide the element");
subNodes[subdivIndex].Subdivide(targetPosition, value, depth - 1);
}
}
public void Visitor_Simple()
{
List <DataRow> data = new List <DataRow>();
data.Add(new DataRow()
{
Argument = 0.5, Value = 0.5,
});
data.Add(new DataRow()
{
Argument = 0, Value = 0,
});
data.Add(new DataRow()
{
Argument = 1, Value = 0,
});
data.Add(new DataRow()
{
Argument = 0, Value = 1,
});
data.Add(new DataRow()
{
Argument = 1, Value = 1,
});
QuadtreeNode startNode = QuardtreeBuilder.BuildTree(data);
List <SimpleNode> result = new List <SimpleNode>();
startNode.VisitNodes(new Tuple <Range, Range>(new Range()
{
Min = -2.0, Max = 2.0
}, new Range()
{
Min = -2.0, Max = 2.0
}), 1, node => { result.Add(node); });
Assert.AreEqual(5, result.Count);
}
private void BuildQuadtreeRecursively(QuadtreeNode <TType>[] quadtree, int index)
{
if (quadtree[index].Depth >= this._depth)
{
return; //We're done if we hit a leaf node
}
//if we have a tree - the root is equal to 0.
//4 x 0 = 0 but if you add one you get the next node. +2 +3 +4 gives the other nodes.
//Then if you're at position 1 and you multiply by 4 then you get 4, add 1 gives you 5 which is the first node in the seconde depth.
int nextNode = 4 * index;
Vector2 deltaX = new Vector2(quadtree[index].Size / 4, 0);
Vector2 deltaY = new Vector2(0, quadtree[index].Size / 4);
quadtree[nextNode + 1] = new QuadtreeNode <TType>(quadtree[index].Position - deltaX + deltaY, quadtree[index].Size / 2, quadtree[index].Depth + 1);
quadtree[nextNode + 2] = new QuadtreeNode <TType>(quadtree[index].Position + deltaX + deltaY, quadtree[index].Size / 2, quadtree[index].Depth + 1);
quadtree[nextNode + 3] = new QuadtreeNode <TType>(quadtree[index].Position - deltaX - deltaY, quadtree[index].Size / 2, quadtree[index].Depth + 1);
quadtree[nextNode + 4] = new QuadtreeNode <TType>(quadtree[index].Position + deltaX - deltaY, quadtree[index].Size / 2, quadtree[index].Depth + 1);
BuildQuadtreeRecursively(quadtree, nextNode + 1);
BuildQuadtreeRecursively(quadtree, nextNode + 2);
BuildQuadtreeRecursively(quadtree, nextNode + 3);
BuildQuadtreeRecursively(quadtree, nextNode + 4);
}
private void Insert(QuadtreeNode <T> node, T value)
{
if (node == null || !node.Intersects(value.Collider))
{
return;
}
if (node.Size <= minSize)
{
node.AddObject(value);
}
else
{
if (node.IsLeaf())
{
Split(node);
}
for (int i = 0; i < 4; i++)
{
Insert(node.children[i], value);
}
}
}
/// <summary>
/// Recursively draws the quadtree terrain nodes that are in the viewing frustum.
/// </summary>
/// <param name="node">The node or leaf to draw.</param>
protected void DrawQuadtree(QuadtreeNode node)
{
if (!(new BoundingFrustum(Matrix.Identity * view * projection)).Intersects(node.boundingBox))
{
return;
}
if (node.GetType() == typeof(QuadtreeLeaf))
{
QuadtreeLeaf leaf = (QuadtreeLeaf)node;
GraphicsDevice.SetVertexBuffer(leaf.vertexBuffer);
GraphicsDevice.Indices = leaf.indexBuffer;
GraphicsDevice.DrawIndexedPrimitives(PrimitiveType.TriangleStrip, 0, 0, leaf.indexBuffer.IndexCount - 4);
}
else
{
DrawQuadtree(node.topLeft);
DrawQuadtree(node.topRight);
DrawQuadtree(node.bottomLeft);
DrawQuadtree(node.bottomRight);
}
}
public Quadtree(float _size, Vector2 _corner, int _maxLevel) {
size = _size;
corner = _corner;
maxLevel = _maxLevel;
root = new QuadtreeNode(0, new int[]{0,0}, null, this);
}
public QuadtreeNode(int _level, int[] _index, QuadtreeNode _parent, Quadtree _tree) {
level = _level;
index = _index;
parent = _parent;
tree = _tree;
}
public virtual void CreateChildren() {
if (children == null) {
children = new QuadtreeNode[2, 2];
for (int xi = 0; xi < 2; xi++)
for (int yi = 0; yi < 2; yi++) {
int[] newIndex = { index[0] * 2 + xi, index[1] * 2 + yi };
children[xi, yi] = new QuadtreeNode(level + 1, newIndex, this, tree);
}
}
}
public override void Build(AABB aabb, List <Body> bodies)
{
potentialCollisionCount = 0;
rootNode = new QuadtreeNode(aabb, capacity);
bodies.ForEach(body => rootNode.Insert(body));
}
// TODO implement
private void split()
{
Children = new QuadtreeNode[4];
Children[0] = new QuadtreeNode(Min, Max);
Children[1] = new QuadtreeNode(Min, Max);
Children[2] = new QuadtreeNode(Min, Max);
Children[3] = new QuadtreeNode(Min, Max);
}