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/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkQuadTree_DEFINED
#define SkQuadTree_DEFINED
#include "SkRect.h"
#include "SkTDArray.h"
#include "SkBBoxHierarchy.h"
#include "SkTInternalSList.h"
#include "SkTObjectPool.h"
/**
* A QuadTree implementation. In short, it is a tree containing a hierarchy of bounding rectangles
* in which each internal node has exactly four children.
*
* For more details see:
*
* http://en.wikipedia.org/wiki/Quadtree
*/
class SkQuadTree : public SkBBoxHierarchy {
public:
SK_DECLARE_INST_COUNT(SkQuadTree)
/**
* Quad tree constructor.
* @param bounds The bounding box for the root of the quad tree.
* giving the quad tree bounds that fall outside the root
* bounds may result in pathological but correct behavior.
*/
SkQuadTree(const SkIRect& bounds);
virtual ~SkQuadTree();
/**
* Insert a node, consisting of bounds and a data value into the tree, if we don't immediately
* need to use the tree; we may allow the insert to be deferred (this can allow us to bulk-load
* a large batch of nodes at once, which tends to be faster and produce a better tree).
* @param data The data value
* @param bounds The corresponding bounding box
* @param defer Can this insert be deferred? (this may be ignored)
*/
virtual void insert(void* data, const SkIRect& bounds, bool defer = false) SK_OVERRIDE;
/**
* If any inserts have been deferred, this will add them into the tree
*/
virtual void flushDeferredInserts() SK_OVERRIDE;
/**
* Given a query rectangle, populates the passed-in array with the elements it intersects
*/
virtual void search(const SkIRect& query, SkTDArray<void*>* results) SK_OVERRIDE;
virtual void clear() SK_OVERRIDE;
/**
* Gets the depth of the tree structure
*/
virtual int getDepth() const SK_OVERRIDE;
/**
* This gets the insertion count (rather than the node count)
*/
virtual int getCount() const SK_OVERRIDE {
return fEntryPool.allocated() - fEntryPool.available();
}
virtual void rewindInserts() SK_OVERRIDE;
private:
struct Entry {
Entry() : fData(NULL) {}
SkIRect fBounds;
void* fData;
SK_DECLARE_INTERNAL_SLIST_INTERFACE(Entry);
};
static const int kChildCount = 4;
struct Node {
Node() {
for (int index=0; index<kChildCount; ++index) {
fChildren[index] = NULL;
}
}
SkTInternalSList<Entry> fEntries;
SkIRect fBounds;
SkIPoint fSplitPoint; // Only valid if the node has children.
Node* fChildren[kChildCount];
SK_DECLARE_INTERNAL_SLIST_ADAPTER(Node, fChildren[0]);
};
SkTObjectPool<Entry> fEntryPool;
SkTObjectPool<Node> fNodePool;
Node* fRoot;
SkIRect fRootBounds;
SkTInternalSList<Entry> fDeferred;
void insert(Node* node, Entry* entry);
void split(Node* node);
void search(Node* node, const SkIRect& query, SkTDArray<void*>* results) const;
void clear(Node* node);
int getDepth(Node* node) const;
typedef SkBBoxHierarchy INHERITED;
};
#endif
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