org.flixel.system.FlxQuadTree Maven / Gradle / Ivy
The newest version!
package org.flixel.system;
import org.flixel.FlxBasic;
import org.flixel.FlxGroup;
import org.flixel.FlxObject;
import org.flixel.FlxRect;
import org.flixel.event.IFlxCollision;
import org.flixel.event.IFlxObject;
import com.badlogic.gdx.utils.Array;
import com.badlogic.gdx.utils.Pool;
/**
* A fairly generic quad tree structure for rapid overlap checks.
* FlxQuadTree is also configured for single or dual list operation.
* You can add items either to its A list or its B list.
* When you do an overlap check, you can compare the A list to itself,
* or the A list against the B list. Handy for different things!
*
* @author Ka Wing Chin
*/
public class FlxQuadTree extends FlxRect
{
/**
* Flag for specifying that you want to add an object to the A list.
*/
static public final int A_LIST = 0;
/**
* Flag for specifying that you want to add an object to the B list.
*/
static public final int B_LIST = 1;
/**
* Controls the granularity of the quad tree. Default is 6 (decent performance on large and small worlds).
*/
static public int divisions;
/**
* Whether this branch of the tree can be subdivided or not.
*/
protected boolean _canSubdivide;
/**
* Refers to the internal A and B linked lists,
* which are used to store objects in the leaves.
*/
protected FlxList _headA;
/**
* Refers to the internal A and B linked lists,
* which are used to store objects in the leaves.
*/
protected FlxList _tailA;
/**
* Refers to the internal A and B linked lists,
* which are used to store objects in the leaves.
*/
protected FlxList _headB;
/**
* Refers to the internal A and B linked lists,
* which are used to store objects in the leaves.
*/
protected FlxList _tailB;
/**
* Internal, governs and assists with the formation of the tree.
*/
static protected int _min;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected FlxQuadTree _northWestTree;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected FlxQuadTree _northEastTree;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected FlxQuadTree _southEastTree;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected FlxQuadTree _southWestTree;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected float _leftEdge;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected float _rightEdge;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected float _topEdge;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected float _bottomEdge;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected float _halfWidth;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected float _halfHeight;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected float _midpointX;
/**
* Internal, governs and assists with the formation of the tree.
*/
protected float _midpointY;
/**
* Internal, used to reduce recursive method parameters during object placement and tree formation.
*/
static protected FlxObject _object;
/**
* Internal, used to reduce recursive method parameters during object placement and tree formation.
*/
static protected float _objectLeftEdge;
/**
* Internal, used to reduce recursive method parameters during object placement and tree formation.
*/
static protected float _objectTopEdge;
/**
* Internal, used to reduce recursive method parameters during object placement and tree formation.
*/
static protected float _objectRightEdge;
/**
* Internal, used to reduce recursive method parameters during object placement and tree formation.
*/
static protected float _objectBottomEdge;
/**
* Internal, used during tree processing and overlap checks.
*/
static protected int _list;
/**
* Internal, used during tree processing and overlap checks.
*/
static protected boolean _useBothLists;
/**
* Internal, used during tree processing and overlap checks.
*/
static protected IFlxObject _processingCallback;
/**
* Internal, used during tree processing and overlap checks.
*/
static protected IFlxCollision _notifyCallback;
/**
* Internal, used during tree processing and overlap checks.
*/
static protected FlxList _iterator;
/**
* Internal, helpers for comparing actual object-to-object overlap - see overlapNode().
*/
static protected float _objectHullX;
/**
* Internal, helpers for comparing actual object-to-object overlap - see overlapNode().
*/
static protected float _objectHullY;
/**
* Internal, helpers for comparing actual object-to-object overlap - see overlapNode().
*/
static protected float _objectHullWidth;
/**
* Internal, helpers for comparing actual object-to-object overlap - see overlapNode().
*/
static protected float _objectHullHeight;
/**
* Internal, helpers for comparing actual object-to-object overlap - see overlapNode().
*/
static protected float _checkObjectHullX;
/**
* Internal, helpers for comparing actual object-to-object overlap - see overlapNode().
*/
static protected float _checkObjectHullY;
/**
* Internal, helpers for comparing actual object-to-object overlap - see overlapNode().
*/
static protected float _checkObjectHullWidth;
/**
* Internal, helpers for comparing actual object-to-object overlap - see overlapNode().
*/
static protected float _checkObjectHullHeight;
/**
* Internal, a pool of FlxQuadTrees to prevent constant new calls.
*/
static private Pool _pool = new Pool()
{
@Override
protected FlxQuadTree newObject()
{
return new FlxQuadTree();
}
};
/**
* Get a new Quad Tree node from the pool.
*
* @param X The X-coordinate of the point in space.
* @param Y The Y-coordinate of the point in space.
* @param Width Desired width of this node.
* @param Height Desired height of this node.
* @param Parent The parent branch or node. Pass null to create a root.
*
* @return A new FlxQuadTree.
*/
static public FlxQuadTree getNew(float X, float Y, float Width, float Height, FlxQuadTree Parent)
{
FlxQuadTree quadTree = _pool.obtain();
quadTree.init(X,Y,Width,Height,Parent);
return quadTree;
}
/**
* Has to be public for GWT reflection.
*/
public FlxQuadTree()
{
}
/**
* Instantiate a new Quad Tree node.
*
* @param X The X-coordinate of the point in space.
* @param Y The Y-coordinate of the point in space.
* @param Width Desired width of this node.
* @param Height Desired height of this node.
* @param Parent The parent branch or node. Pass null to create a root.
*/
protected void init(float X, float Y, float Width, float Height, FlxQuadTree Parent)
{
make(X,Y,Width,Height);
_headA = _tailA = FlxList.getNew();
_headB = _tailB = FlxList.getNew();
//Copy the parent's children (if there are any)
if(Parent != null)
{
FlxList iterator;
FlxList ot;
if(Parent._headA.object != null)
{
iterator = Parent._headA;
while(iterator != null)
{
if(_tailA.object != null)
{
ot = _tailA;
_tailA = FlxList.getNew();
ot.next = _tailA;
}
_tailA.object = iterator.object;
iterator = iterator.next;
}
}
if(Parent._headB.object != null)
{
iterator = Parent._headB;
while(iterator != null)
{
if(_tailB.object != null)
{
ot = _tailB;
_tailB = FlxList.getNew();
ot.next = _tailB;
}
_tailB.object = iterator.object;
iterator = iterator.next;
}
}
}
else
_min = (int)((width + height)/(2*divisions));
_canSubdivide = (width > _min) || (height > _min);
//Set up comparison/sort helpers
_northWestTree = null;
_northEastTree = null;
_southEastTree = null;
_southWestTree = null;
_leftEdge = x;
_rightEdge = x+width;
_halfWidth = width/2f;
_midpointX = _leftEdge+_halfWidth;
_topEdge = y;
_bottomEdge = y+height;
_halfHeight = height/2f;
_midpointY = _topEdge+_halfHeight;
}
/**
* Instantiate a new Quad Tree node.
*
* @param X The X-coordinate of the point in space.
* @param Y The Y-coordinate of the point in space.
* @param Width Desired width of this node.
* @param Height Desired height of this node.
*/
protected void init(float X, float Y, float Width, float Height)
{
init(X, Y, Width, Height, null);
}
/**
* Clean up memory.
*/
public void destroy()
{
if(_headA != null)
_headA.destroy();
_headA = null;
//if(_tailA != null)
// _tailA.destroy();
_tailA = null;
if(_headB != null)
_headB.destroy();
_headB = null;
//if(_tailB != null)
// _tailB.destroy();
_tailB = null;
if(_northWestTree != null)
_northWestTree.destroy();
_northWestTree = null;
if(_northEastTree != null)
_northEastTree.destroy();
_northEastTree = null;
if(_southEastTree != null)
_southEastTree.destroy();
_southEastTree = null;
if(_southWestTree != null)
_southWestTree.destroy();
_southWestTree = null;
_object = null;
_processingCallback = null;
_notifyCallback = null;
_pool.free(this);
}
/**
* Load objects and/or groups into the quad tree, and register notify and processing callbacks.
*
* @param ObjectOrGroup1 Any object that is or extends FlxObject or FlxGroup.
* @param ObjectOrGroup2 Any object that is or extends FlxObject or FlxGroup. If null, the first parameter will be checked against itself.
* @param NotifyCallback A function with the form myFunction(Object1:FlxObject,Object2:FlxObject):void that is called whenever two objects are found to overlap in world space, and either no ProcessCallback is specified, or the ProcessCallback returns true.
* @param ProcessCallback A function with the form myFunction(Object1:FlxObject,Object2:FlxObject):Boolean that is called whenever two objects are found to overlap in world space. The NotifyCallback is only called if this function returns true. See FlxObject.separate().
*/
public void load(FlxBasic ObjectOrGroup1, FlxBasic ObjectOrGroup2, IFlxCollision NotifyCallback, IFlxObject ProcessCallback)
{
add(ObjectOrGroup1, A_LIST);
if(ObjectOrGroup2 != null)
{
add(ObjectOrGroup2, B_LIST);
_useBothLists = true;
}
else
_useBothLists = false;
_notifyCallback = NotifyCallback;
_processingCallback = ProcessCallback;
}
/**
* Load objects and/or groups into the quad tree, and register notify and processing callbacks.
*
* @param ObjectOrGroup1 Any object that is or extends FlxObject or FlxGroup.
* @param ObjectOrGroup2 Any object that is or extends FlxObject or FlxGroup. If null, the first parameter will be checked against itself.
* @param NotifyCallback A function with the form myFunction(Object1:FlxObject,Object2:FlxObject):void that is called whenever two objects are found to overlap in world space, and either no ProcessCallback is specified, or the ProcessCallback returns true.
*/
public void load(FlxBasic ObjectOrGroup1, FlxBasic ObjectOrGroup2, IFlxCollision NotifyCallback)
{
load(ObjectOrGroup1, ObjectOrGroup2, NotifyCallback, null);
}
/**
* Load objects and/or groups into the quad tree, and register notify and processing callbacks.
*
* @param ObjectOrGroup1 Any object that is or extends FlxObject or FlxGroup.
* @param ObjectOrGroup2 Any object that is or extends FlxObject or FlxGroup. If null, the first parameter will be checked against itself.
*/
public void load(FlxBasic ObjectOrGroup1, FlxBasic ObjectOrGroup2)
{
load(ObjectOrGroup1, ObjectOrGroup2, null, null);
}
/**
* Call this function to add an object to the root of the tree.
* This function will recursively add all group members, but
* not the groups themselves.
*
* @param ObjectOrGroup FlxObjects are just added, FlxGroups are recursed and their applicable members added accordingly.
* @param List A int flag indicating the list to which you want to add the objects. Options are A_LIST and B_LIST.
*/
public void add(FlxBasic ObjectOrGroup, int List)
{
_list = List;
if(ObjectOrGroup instanceof FlxGroup)
{
int i = 0;
FlxBasic basic;
Array members = ((FlxGroup) ObjectOrGroup).members;
int l = ((FlxGroup) (ObjectOrGroup)).length;
while(i < l)
{
basic = members.get(i++);
if((basic != null) && basic.exists)
{
if(basic instanceof FlxGroup)
add(basic,List);
else if(basic instanceof FlxObject)
{
_object = (FlxObject) basic;
if(_object.exists && _object.allowCollisions > 0)
{
_objectLeftEdge = _object.x;
_objectTopEdge = _object.y;
_objectRightEdge = _object.x + _object.width;
_objectBottomEdge = _object.y + _object.height;
addObject();
}
}
}
}
}
else
{
_object = (FlxObject) ObjectOrGroup;
if(_object.exists && _object.allowCollisions > 0)
{
_objectLeftEdge = _object.x;
_objectTopEdge = _object.y;
_objectRightEdge = _object.x + _object.width;
_objectBottomEdge = _object.y + _object.height;
addObject();
}
}
}
/**
* Internal function for recursively navigating and creating the tree
* while adding objects to the appropriate nodes.
*/
protected void addObject()
{
//If this quad (not its children) lies entirely inside this object, add it here
if(!_canSubdivide || ((_leftEdge >= _objectLeftEdge) && (_rightEdge <= _objectRightEdge) && (_topEdge >= _objectTopEdge) && (_bottomEdge <= _objectBottomEdge)))
{
addToList();
return;
}
//See if the selected object fits completely inside any of the quadrants
if((_objectLeftEdge > _leftEdge) && (_objectRightEdge < _midpointX))
{
if((_objectTopEdge > _topEdge) && (_objectBottomEdge < _midpointY))
{
if(_northWestTree == null)
_northWestTree = FlxQuadTree.getNew(_leftEdge,_topEdge,_halfWidth,_halfHeight,this);
_northWestTree.addObject();
return;
}
if((_objectTopEdge > _midpointY) && (_objectBottomEdge < _bottomEdge))
{
if(_southWestTree == null)
_southWestTree = FlxQuadTree.getNew(_leftEdge,_midpointY,_halfWidth,_halfHeight,this);
_southWestTree.addObject();
return;
}
}
if((_objectLeftEdge > _midpointX) && (_objectRightEdge < _rightEdge))
{
if((_objectTopEdge > _topEdge) && (_objectBottomEdge < _midpointY))
{
if(_northEastTree == null)
_northEastTree = FlxQuadTree.getNew(_midpointX,_topEdge,_halfWidth,_halfHeight,this);
_northEastTree.addObject();
return;
}
if((_objectTopEdge > _midpointY) && (_objectBottomEdge < _bottomEdge))
{
if(_southEastTree == null)
_southEastTree = FlxQuadTree.getNew(_midpointX,_midpointY,_halfWidth,_halfHeight,this);
_southEastTree.addObject();
return;
}
}
//If it wasn't completely contained we have to check out the partial overlaps
if((_objectRightEdge > _leftEdge) && (_objectLeftEdge < _midpointX) && (_objectBottomEdge > _topEdge) && (_objectTopEdge < _midpointY))
{
if(_northWestTree == null)
_northWestTree = FlxQuadTree.getNew(_leftEdge,_topEdge,_halfWidth,_halfHeight,this);
_northWestTree.addObject();
}
if((_objectRightEdge > _midpointX) && (_objectLeftEdge < _rightEdge) && (_objectBottomEdge > _topEdge) && (_objectTopEdge < _midpointY))
{
if(_northEastTree == null)
_northEastTree = FlxQuadTree.getNew(_midpointX,_topEdge,_halfWidth,_halfHeight,this);
_northEastTree.addObject();
}
if((_objectRightEdge > _midpointX) && (_objectLeftEdge < _rightEdge) && (_objectBottomEdge > _midpointY) && (_objectTopEdge < _bottomEdge))
{
if(_southEastTree == null)
_southEastTree = FlxQuadTree.getNew(_midpointX,_midpointY,_halfWidth,_halfHeight,this);
_southEastTree.addObject();
}
if((_objectRightEdge > _leftEdge) && (_objectLeftEdge < _midpointX) && (_objectBottomEdge > _midpointY) && (_objectTopEdge < _bottomEdge))
{
if(_southWestTree == null)
_southWestTree = FlxQuadTree.getNew(_leftEdge,_midpointY,_halfWidth,_halfHeight,this);
_southWestTree.addObject();
}
}
/**
* Internal function for recursively adding objects to leaf lists.
*/
protected void addToList()
{
FlxList ot;
if(_list == A_LIST)
{
if(_tailA.object != null)
{
ot = _tailA;
_tailA = FlxList.getNew();
ot.next = _tailA;
}
_tailA.object = _object;
}
else
{
if(_tailB.object != null)
{
ot = _tailB;
_tailB = FlxList.getNew();
ot.next = _tailB;
}
_tailB.object = _object;
}
if(!_canSubdivide)
return;
if(_northWestTree != null)
_northWestTree.addToList();
if(_northEastTree != null)
_northEastTree.addToList();
if(_southEastTree != null)
_southEastTree.addToList();
if(_southWestTree != null)
_southWestTree.addToList();
}
/**
* FlxQuadTree's other main function. Call this after adding objects
* using FlxQuadTree.load() to compare the objects that you loaded.
*
* @return Whether or not any overlaps were found.
*/
public boolean execute()
{
boolean overlapProcessed = false;
FlxList iterator;
if(_headA.object != null)
{
iterator = _headA;
while(iterator != null)
{
_object = iterator.object;
if(_useBothLists)
_iterator = _headB;
else
_iterator = iterator.next;
if(_object.exists && (_object.allowCollisions > 0) && (_iterator != null) && (_iterator.object != null) && _iterator.object.exists && overlapNode())
{
overlapProcessed = true;
}
iterator = iterator.next;
}
}
//Advance through the tree by calling overlap on each child
if((_northWestTree != null) && _northWestTree.execute())
overlapProcessed = true;
if((_northEastTree != null) && _northEastTree.execute())
overlapProcessed = true;
if((_southEastTree != null) && _southEastTree.execute())
overlapProcessed = true;
if((_southWestTree != null) && _southWestTree.execute())
overlapProcessed = true;
return overlapProcessed;
}
/**
* An internal function for comparing an object against the contents of a node.
*
* @return Whether or not any overlaps were found.
*/
protected boolean overlapNode()
{
//Walk the list and check for overlaps
boolean overlapProcessed = false;
FlxObject checkObject;
while(_iterator != null)
{
if(!_object.exists || (_object.allowCollisions <= 0))
break;
checkObject = _iterator.object;
if((_object == checkObject) || ((_object != null) && (_object.equals(checkObject))) || !checkObject.exists || (checkObject.allowCollisions <= 0))
{
_iterator = _iterator.next;
continue;
}
//calculate bulk hull for _object
_objectHullX = (_object.x < _object.last.x)?_object.x:_object.last.x;
_objectHullY = (_object.y < _object.last.y)?_object.y:_object.last.y;
_objectHullWidth = _object.x - _object.last.x;
_objectHullWidth = _object.width + ((_objectHullWidth>0)?_objectHullWidth:-_objectHullWidth);
_objectHullHeight = _object.y - _object.last.y;
_objectHullHeight = _object.height + ((_objectHullHeight>0)?_objectHullHeight:-_objectHullHeight);
//calculate bulk hull for checkObject
_checkObjectHullX = (checkObject.x < checkObject.last.x)?checkObject.x:checkObject.last.x;
_checkObjectHullY = (checkObject.y < checkObject.last.y)?checkObject.y:checkObject.last.y;
_checkObjectHullWidth = checkObject.x - checkObject.last.x;
_checkObjectHullWidth = checkObject.width + ((_checkObjectHullWidth>0)?_checkObjectHullWidth:-_checkObjectHullWidth);
_checkObjectHullHeight = checkObject.y - checkObject.last.y;
_checkObjectHullHeight = checkObject.height + ((_checkObjectHullHeight>0)?_checkObjectHullHeight:-_checkObjectHullHeight);
//check for intersection of the two hulls
if( (_objectHullX + _objectHullWidth > _checkObjectHullX) &&
(_objectHullX < _checkObjectHullX + _checkObjectHullWidth) &&
(_objectHullY + _objectHullHeight > _checkObjectHullY) &&
(_objectHullY < _checkObjectHullY + _checkObjectHullHeight) )
{
//Execute callback functions if they exist
if((_processingCallback == null) || _processingCallback.callback(_object,checkObject))
{
overlapProcessed = true;
if(_notifyCallback != null)
_notifyCallback.callback(_object,checkObject);
}
}
_iterator = _iterator.next;
}
return overlapProcessed;
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy