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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.
*/
#include "SkQuadTree.h"
#include "SkTSort.h"
#include <stdio.h>
#include <vector>
class SkQuadTree::QuadTreeNode {
public:
struct Data {
Data(const SkIRect& bounds, void* data) : fBounds(bounds), fInnerBounds(bounds), fData(data) {}
SkIRect fBounds;
SkIRect fInnerBounds;
void* fData;
};
QuadTreeNode(const SkIRect& bounds)
: fBounds(bounds)
, fTopLeft(NULL)
, fTopRight(NULL)
, fBottomLeft(NULL)
, fBottomRight(NULL)
, fCanSubdivide((fBounds.width() * fBounds.height()) > 0) {}
~QuadTreeNode() {
clear();
}
void clear() {
SkDELETE(fTopLeft);
fTopLeft = NULL;
SkDELETE(fTopRight);
fTopRight = NULL;
SkDELETE(fBottomLeft);
fBottomLeft = NULL;
SkDELETE(fBottomRight);
fBottomRight = NULL;
fData.reset();
}
const SkIRect& getBounds() const { return fBounds; }
// Insert data into the QuadTreeNode
bool insert(Data& data) {
// Ignore objects which do not belong in this quad tree
return data.fInnerBounds.intersect(fBounds) && doInsert(data);
}
// Find all data which appear within a range
void queryRange(const SkIRect& range, SkTDArray<void*>* dataInRange) const {
// Automatically abort if the range does not collide with this quad
if (!SkIRect::Intersects(fBounds, range)) {
return; // nothing added to the list
}
// Check objects at this quad level
for (int i = 0; i < fData.count(); ++i) {
if (SkIRect::Intersects(fData[i].fBounds, range)) {
dataInRange->push(fData[i].fData);
}
}
// Terminate here, if there are no children
if (!hasChildren()) {
return;
}
// Otherwise, add the data from the children
fTopLeft->queryRange(range, dataInRange);
fTopRight->queryRange(range, dataInRange);
fBottomLeft->queryRange(range, dataInRange);
fBottomRight->queryRange(range, dataInRange);
}
int getDepth(int i = 1) const {
if (hasChildren()) {
int depthTL = fTopLeft->getDepth(++i);
int depthTR = fTopRight->getDepth(i);
int depthBL = fBottomLeft->getDepth(i);
int depthBR = fBottomRight->getDepth(i);
return SkTMax(SkTMax(depthTL, depthTR), SkTMax(depthBL, depthBR));
}
return i;
}
void rewindInserts(SkBBoxHierarchyClient* client) {
for (int i = fData.count() - 1; i >= 0; --i) {
if (client->shouldRewind(fData[i].fData)) {
fData.remove(i);
}
}
if (hasChildren()) {
fTopLeft->rewindInserts(client);
fTopRight->rewindInserts(client);
fBottomLeft->rewindInserts(client);
fBottomRight->rewindInserts(client);
}
}
private:
// create four children which fully divide this quad into four quads of equal area
void subdivide() {
if (!hasChildren() && fCanSubdivide) {
SkIPoint center = SkIPoint::Make(fBounds.centerX(), fBounds.centerY());
fTopLeft = SkNEW_ARGS(QuadTreeNode, (SkIRect::MakeLTRB(
fBounds.fLeft, fBounds.fTop, center.fX, center.fY)));
fTopRight = SkNEW_ARGS(QuadTreeNode, (SkIRect::MakeLTRB(
center.fX, fBounds.fTop, fBounds.fRight, center.fY)));
fBottomLeft = SkNEW_ARGS(QuadTreeNode, (SkIRect::MakeLTRB(
fBounds.fLeft, center.fY, center.fX, fBounds.fBottom)));
fBottomRight = SkNEW_ARGS(QuadTreeNode, (SkIRect::MakeLTRB(
center.fX, center.fY, fBounds.fRight, fBounds.fBottom)));
// If any of the data can fit entirely into a subregion, move it down now
for (int i = fData.count() - 1; i >= 0; --i) {
// If the data fits entirely into one of the 4 subregions, move that data
// down to that subregion.
if (fTopLeft->doInsert(fData[i]) ||
fTopRight->doInsert(fData[i]) ||
fBottomLeft->doInsert(fData[i]) ||
fBottomRight->doInsert(fData[i])) {
fData.remove(i);
}
}
}
}
bool doInsert(const Data& data) {
if (!fBounds.contains(data.fInnerBounds)) {
return false;
}
if (fData.count() > kQuadTreeNodeCapacity) {
subdivide();
}
// If there is space in this quad tree, add the object here
// If this quadtree can't be subdivided, we have no choice but to add it here
if ((fData.count() <= kQuadTreeNodeCapacity) || !fCanSubdivide) {
if (fData.isEmpty()) {
fData.setReserve(kQuadTreeNodeCapacity);
}
fData.push(data);
} else if (!fTopLeft->doInsert(data) && !fTopRight->doInsert(data) &&
!fBottomLeft->doInsert(data) && !fBottomRight->doInsert(data)) {
// Can't be pushed down to children ? keep it here
fData.push(data);
}
return true;
}
bool hasChildren() const {
return (NULL != fTopLeft);
}
// Arbitrary constant to indicate how many elements can be stored in this quad tree node
enum { kQuadTreeNodeCapacity = 4 };
// Bounds of this quad tree
SkIRect fBounds;
// Data in this quad tree node
SkTDArray<Data> fData;
// Children
QuadTreeNode* fTopLeft;
QuadTreeNode* fTopRight;
QuadTreeNode* fBottomLeft;
QuadTreeNode* fBottomRight;
// Whether or not this node can have children
bool fCanSubdivide;
};
///////////////////////////////////////////////////////////////////////////////////////////////////
SkQuadTree* SkQuadTree::Create(const SkIRect& bounds) {
return new SkQuadTree(bounds);
}
SkQuadTree::SkQuadTree(const SkIRect& bounds)
: fCount(0)
, fRoot(SkNEW_ARGS(QuadTreeNode, (bounds))) {
SkASSERT((bounds.width() * bounds.height()) > 0);
}
SkQuadTree::~SkQuadTree() {
SkDELETE(fRoot);
}
void SkQuadTree::insert(void* data, const SkIRect& bounds, bool) {
if (bounds.isEmpty()) {
SkASSERT(false);
return;
}
QuadTreeNode::Data quadTreeData(bounds, data);
fRoot->insert(quadTreeData);
++fCount;
}
void SkQuadTree::search(const SkIRect& query, SkTDArray<void*>* results) {
SkASSERT(NULL != results);
fRoot->queryRange(query, results);
}
void SkQuadTree::clear() {
fCount = 0;
fRoot->clear();
}
int SkQuadTree::getDepth() const {
return fRoot->getDepth();
}
void SkQuadTree::rewindInserts() {
SkASSERT(fClient);
fRoot->rewindInserts(fClient);
}
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