path: root/indra/llmath/lloctree.h

/**
 * @file lloctree.h
 * @brief Octree declaration.
 *
 * $LicenseInfo:firstyear=2005&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLOCTREE_H
#define LL_LLOCTREE_H

#include "lltreenode.h"
#include "v3math.h"
#include "llvector4a.h"
#include <vector>

#define OCT_ERRS LL_WARNS("OctreeErrors")

#define OCTREE_DEBUG_COLOR_REMOVE   0x0000FF // r
#define OCTREE_DEBUG_COLOR_INSERT   0x00FF00 // g
#define OCTREE_DEBUG_COLOR_BALANCE  0xFF0000 // b

extern U32 gOctreeMaxCapacity;
extern float gOctreeMinSize;

/*#define LL_OCTREE_PARANOIA_CHECK 0
#if LL_DARWIN
#define LL_OCTREE_MAX_CAPACITY 32
#else
#define LL_OCTREE_MAX_CAPACITY 128
#endif*/

// T is the type of the element referenced by the octree node.
// T_PTR determines how pointers to elements are stored internally.
// LLOctreeNode<T, LLPointer<T>> assumes ownership of inserted elements and
// deletes elements removed from the tree.
// LLOctreeNode<T, T*> doesn't take ownership of inserted elements, so the API
// user is responsible for managing the storage lifecycle of elements added to
// the tree.
template <class T, typename T_PTR> class LLOctreeNode;

template <class T, typename T_PTR>
class LLOctreeListener: public LLTreeListener<T>
{
public:
    typedef LLTreeListener<T> BaseType;
    typedef LLOctreeNode<T, T_PTR> oct_node;

    virtual void handleChildAddition(const oct_node* parent, oct_node* child) = 0;
    virtual void handleChildRemoval(const oct_node* parent, const oct_node* child) = 0;
};

template <class T, typename T_PTR>
class LLOctreeTraveler
{
public:
    virtual void traverse(const LLOctreeNode<T, T_PTR>* node);
    virtual void visit(const LLOctreeNode<T, T_PTR>* branch) = 0;
};

template <class T, typename T_PTR>
class LLOctreeTravelerDepthFirst : public LLOctreeTraveler<T, T_PTR>
{
public:
    virtual void traverse(const LLOctreeNode<T, T_PTR>* node) override;
};

template <class T, typename T_PTR>
class alignas(16) LLOctreeNode : public LLTreeNode<T>
{
    LL_ALIGN_NEW
public:

    typedef LLOctreeTraveler<T, T_PTR>                          oct_traveler;
    typedef LLTreeTraveler<T>                                   tree_traveler;
    typedef std::vector<T_PTR>                                  element_list;
    typedef typename element_list::iterator                     element_iter;
    typedef typename element_list::const_iterator               const_element_iter;
    typedef typename std::vector<LLTreeListener<T>*>::iterator  tree_listener_iter;
    typedef LLOctreeNode<T, T_PTR>**                            child_list;
    typedef LLOctreeNode<T, T_PTR>**                            child_iter;

    typedef LLTreeNode<T>               BaseType;
    typedef LLOctreeNode<T, T_PTR>      oct_node;
    typedef LLOctreeListener<T, T_PTR>  oct_listener;

    enum
    {
        NO_CHILD_NODES = 255 // Note: This is an U8 to match the max value in mChildMap[]
    };

    LLOctreeNode(   const LLVector4a& center,
                    const LLVector4a& size,
                    BaseType* parent,
                    U8 octant = NO_CHILD_NODES)
    :   mParent((oct_node*)parent),
        mOctant(octant)
    {
        llassert(size[0] >= gOctreeMinSize*0.5f);

        mCenter = center;
        mSize = size;

        updateMinMax();
        if ((mOctant == NO_CHILD_NODES) && mParent)
        {
            mOctant = ((oct_node*) mParent)->getOctant(mCenter);
        }

        clearChildren();
    }

    virtual ~LLOctreeNode()
    {
        BaseType::destroyListeners();

        const U32 element_count = getElementCount();
        for (U32 i = 0; i < element_count; ++i)
        {
            mData[i]->setBinIndex(-1);
            mData[i] = NULL;
        }

        mData.clear();

        for (U32 i = 0; i < getChildCount(); i++)
        {
            delete getChild(i);
        }
    }

    inline const BaseType* getParent()  const           { return mParent; }
    inline void setParent(BaseType* parent)             { mParent = (oct_node*) parent; }
    inline const LLVector4a& getCenter() const          { return mCenter; }
    inline const LLVector4a& getSize() const            { return mSize; }
    inline void setCenter(const LLVector4a& center)     { mCenter = center; }
    inline void setSize(const LLVector4a& size)         { mSize = size; }
    inline oct_node* getNodeAt(T* data)                 { return getNodeAt(data->getPositionGroup(), data->getBinRadius()); }
    inline U8 getOctant() const                         { return mOctant; }
    inline const oct_node*  getOctParent() const        { return (const oct_node*) getParent(); }
    inline oct_node* getOctParent()                     { return (oct_node*) getParent(); }

    U8 getOctant(const LLVector4a& pos) const           //get the octant pos is in
    {
        return (U8) (pos.greaterThan(mCenter).getGatheredBits() & 0x7);
    }

    inline bool isInside(const LLVector4a& pos, const F32& rad) const
    {
        return rad <= mSize[0]*2.f && isInside(pos);
    }

    inline bool isInside(T* data) const
    {
        return isInside(data->getPositionGroup(), data->getBinRadius());
    }

    bool isInside(const LLVector4a& pos) const
    {
        S32 gt = pos.greaterThan(mMax).getGatheredBits() & 0x7;
        if (gt)
        {
            return false;
        }

        S32 lt = pos.lessEqual(mMin).getGatheredBits() & 0x7;
        if (lt)
        {
            return false;
        }

        return true;
    }

    void updateMinMax()
    {
        mMax.setAdd(mCenter, mSize);
        mMin.setSub(mCenter, mSize);
    }

    inline oct_listener* getOctListener(U32 index)
    {
        return (oct_listener*) BaseType::getListener(index);
    }

    inline bool contains(T* xform)
    {
        return contains(xform->getBinRadius());
    }

    bool contains(F32 radius)
    {
        if (mParent == NULL)
        {   //root node contains nothing
            return false;
        }

        F32 size = mSize[0];
        F32 p_size = size * 2.f;

        return (radius <= gOctreeMinSize && size <= gOctreeMinSize) ||
                (radius <= p_size && radius > size);
    }

    static void pushCenter(LLVector4a &center, const LLVector4a &size, const T* data)
    {
        const LLVector4a& pos = data->getPositionGroup();

        LLVector4Logical gt = pos.greaterThan(center);

        LLVector4a up;
        up = _mm_and_ps(size, gt);

        LLVector4a down;
        down = _mm_andnot_ps(gt, size);

        center.add(up);
        center.sub(down);
    }

    void accept(oct_traveler* visitor)              { visitor->visit(this); }
    virtual bool isLeaf() const                     { return mChildCount == 0; }

    U32 getElementCount() const                     { return (U32)mData.size(); }
    bool isEmpty() const                            { return mData.empty(); }
    element_iter getDataBegin()                     { return mData.begin(); }
    element_iter getDataEnd()                       { return mData.end(); }
    const_element_iter getDataBegin() const         { return mData.cbegin(); }
    const_element_iter getDataEnd() const           { return mData.cend(); }

    U32 getChildCount() const                       { return mChildCount; }
    oct_node* getChild(U32 index)                   { return mChild[index]; }
    const oct_node* getChild(U32 index) const       { return mChild[index]; }
    child_list& getChildren()                       { return mChild; }
    const child_list& getChildren() const           { return mChild; }

    void accept(tree_traveler* visitor) const       { visitor->visit(this); }
    void accept(oct_traveler* visitor) const        { visitor->visit(this); }

    void validateChildMap()
    {
        for (U32 i = 0; i < 8; i++)
        {
            U8 idx = mChildMap[i];
            if (idx != NO_CHILD_NODES)
            {
                oct_node* child = mChild[idx];

                if (child->getOctant() != i)
                {
                    LL_ERRS() << "Invalid child map, bad octant data." << LL_ENDL;
                }

                if (getOctant(child->getCenter()) != child->getOctant())
                {
                    LL_ERRS() << "Invalid child octant compared to position data." << LL_ENDL;
                }
            }
        }
    }


    oct_node* getNodeAt(const LLVector4a& pos, const F32& rad)
    {
        oct_node* node = this;

        if (node->isInside(pos, rad))
        {
            //do a quick search by octant
            U8 octant = node->getOctant(pos);

            //traverse the tree until we find a node that has no node
            //at the appropriate octant or is smaller than the object.
            //by definition, that node is the smallest node that contains
            // the data
            U8 next_node = node->mChildMap[octant];

            while (next_node != NO_CHILD_NODES && node->getSize()[0] >= rad)
            {
                node = node->getChild(next_node);
                octant = node->getOctant(pos);
                next_node = node->mChildMap[octant];
            }
        }
        else if (!node->contains(rad) && node->getParent())
        { //if we got here, data does not exist in this node
            return ((oct_node*) node->getParent())->getNodeAt(pos, rad);
        }

        return node;
    }

    virtual bool insert(T* data)
    {
        //LL_PROFILE_ZONE_NAMED_COLOR("Octree::insert()",OCTREE_DEBUG_COLOR_INSERT);

        if (data == NULL || data->getBinIndex() != -1)
        {
            OCT_ERRS << "!!! INVALID ELEMENT ADDED TO OCTREE BRANCH !!!" << LL_ENDL;
            return false;
        }
        oct_node* parent = getOctParent();

        //is it here?
        if (isInside(data->getPositionGroup()))
        {
            if ((((getElementCount() < gOctreeMaxCapacity || getSize()[0] <= gOctreeMinSize) && contains(data->getBinRadius())) ||
                (data->getBinRadius() > getSize()[0] && parent && parent->getElementCount() >= gOctreeMaxCapacity)))
            { //it belongs here
                mData.push_back(data);
                data->setBinIndex(getElementCount() - 1);
                BaseType::insert(data);
                return true;
            }
            else
            {
                //find a child to give it to
                oct_node* child = NULL;
                for (U32 i = 0; i < getChildCount(); i++)
                {
                    child = getChild(i);
                    if (child->isInside(data->getPositionGroup()))
                    {
                        child->insert(data);
                        return false;
                    }
                }

                //it's here, but no kids are in the right place, make a new kid
                LLVector4a center = getCenter();
                LLVector4a size = getSize();
                size.mul(0.5f);

                //push center in direction of data
                oct_node::pushCenter(center, size, data);

                // handle case where floating point number gets too small
                LLVector4a val;
                val.setSub(center, getCenter());
                val.setAbs(val);
                LLVector4a min_diff(gOctreeMinSize);

                S32 lt = val.lessThan(min_diff).getGatheredBits() & 0x7;

                if( lt == 0x7 )
                {
                    mData.push_back(data);
                    data->setBinIndex(getElementCount() - 1);
                    BaseType::insert(data);
                    return true;
                }

#if LL_OCTREE_PARANOIA_CHECK
                if (getChildCount() == 8)
                {
                    //this really isn't possible, something bad has happened
                    OCT_ERRS << "Octree detected floating point error and gave up." << LL_ENDL;
                    return false;
                }

                //make sure no existing node matches this position
                for (U32 i = 0; i < getChildCount(); i++)
                {
                    if (mChild[i]->getCenter().equals3(center))
                    {
                        OCT_ERRS << "Octree detected duplicate child center and gave up." << LL_ENDL;
                        return false;
                    }
                }
#endif

                llassert(size[0] >= gOctreeMinSize*0.5f);
                //make the new kid
                child = new oct_node(center, size, this);
                addChild(child);

                child->insert(data);
            }
        }
        else if (parent)
        {
            //it's not in here, give it to the root
            OCT_ERRS << "Octree insertion failed, starting over from root!" << LL_ENDL;

            oct_node* node = this;

            while (parent)
            {
                node = parent;
                parent = node->getOctParent();
            }

            node->insert(data);
        }
        else
        {
            // It's not in here, and we are root.
            // LLOctreeRoot::insert() should have expanded
            // root by now, something is wrong
            OCT_ERRS << "Octree insertion failed! Root expansion failed." << LL_ENDL;
        }

        return false;
    }

    void _remove(T* data, S32 i)
    { //precondition -- getElementCount() > 0, idx is in range [0, getElementCount())

        data->setBinIndex(-1);

        const U32 new_element_count = getElementCount() - 1;
        if (new_element_count > 0)
        {
            if (new_element_count != i)
            {
                mData[i] = mData[new_element_count]; //might unref data, do not access data after this point
                mData[i]->setBinIndex(i);
            }

            mData[new_element_count] = NULL;
            mData.pop_back();
        }
        else
        {
            mData.clear();
        }

        this->notifyRemoval(data);
        checkAlive();
    }

    bool remove(T* data)
    {
        //LL_PROFILE_ZONE_NAMED_COLOR("Octree::remove()", OCTREE_DEBUG_COLOR_REMOVE);

        S32 i = data->getBinIndex();

        if (i >= 0 && i < (S32)getElementCount())
        {
            if (mData[i] == data)
            { //found it
                _remove(data, i);
                llassert(data->getBinIndex() == -1);
                return true;
            }
        }

        if (isInside(data))
        {
            oct_node* dest = getNodeAt(data);

            if (dest != this)
            {
                bool ret = dest->remove(data);
                llassert(data->getBinIndex() == -1);
                return ret;
            }
        }

        //SHE'S GONE MISSING...
        //none of the children have it, let's just brute force this bastard out
        //starting with the root node (UGLY CODE COMETH!)
        oct_node* parent = getOctParent();
        oct_node* node = this;

        while (parent != NULL)
        {
            node = parent;
            parent = node->getOctParent();
        }

        //node is now root
        LL_WARNS() << "!!! OCTREE REMOVING ELEMENT BY ADDRESS, SEVERE PERFORMANCE PENALTY |||" << LL_ENDL;
        node->removeByAddress(data);
        llassert(data->getBinIndex() == -1);
        return true;
    }

    void removeByAddress(T* data)
    {
        const U32 element_count = getElementCount();
        for (U32 i = 0; i < element_count; ++i)
        {
            if (mData[i] == data)
            { //we have data
                _remove(data, i);
                LL_WARNS() << "FOUND!" << LL_ENDL;
                return;
            }
        }

        for (U32 i = 0; i < getChildCount(); i++)
        {   //we don't contain data, so pass this guy down
            oct_node* child = (oct_node*) getChild(i);
            child->removeByAddress(data);
        }
    }

    void clearChildren()
    {
        mChildCount = 0;
        memset(mChildMap, NO_CHILD_NODES, sizeof(mChildMap));
    }

    void validate()
    {
#if LL_OCTREE_PARANOIA_CHECK
        for (U32 i = 0; i < getChildCount(); i++)
        {
            mChild[i]->validate();
            if (mChild[i]->getParent() != this)
            {
                LL_ERRS() << "Octree child has invalid parent." << LL_ENDL;
            }
        }
#endif
    }

    virtual bool balance()
    {
        return false;
    }

    void destroy()
    {
        for (U32 i = 0; i < getChildCount(); i++)
        {
            mChild[i]->destroy();
            delete mChild[i];
        }
    }

    void addChild(oct_node* child, bool silent = false)
    {
#if LL_OCTREE_PARANOIA_CHECK

        if (child->getSize().equals3(getSize()))
        {
            OCT_ERRS << "Child size is same as parent size!" << LL_ENDL;
        }

        for (U32 i = 0; i < getChildCount(); i++)
        {
            if(!mChild[i]->getSize().equals3(child->getSize()))
            {
                OCT_ERRS <<"Invalid octree child size." << LL_ENDL;
            }
            if (mChild[i]->getCenter().equals3(child->getCenter()))
            {
                OCT_ERRS <<"Duplicate octree child position." << LL_ENDL;
            }
        }

        if (mChild.size() >= 8)
        {
            OCT_ERRS <<"Octree node has too many children... why?" << LL_ENDL;
        }
#endif

        mChildMap[child->getOctant()] = mChildCount;

        mChild[mChildCount] = child;
        ++mChildCount;
        child->setParent(this);

        if (!silent)
        {
            for (U32 i = 0; i < this->getListenerCount(); i++)
            {
                oct_listener* listener = getOctListener(i);
                listener->handleChildAddition(this, child);
            }
        }
    }

    void removeChild(S32 index, bool destroy = false)
    {
        for (U32 i = 0; i < this->getListenerCount(); i++)
        {
            oct_listener* listener = getOctListener(i);
            listener->handleChildRemoval(this, getChild(index));
        }

        if (destroy)
        {
            mChild[index]->destroy();
            delete mChild[index];
        }

        --mChildCount;

        mChild[index] = mChild[mChildCount];

        //rebuild child map
        memset(mChildMap, NO_CHILD_NODES, sizeof(mChildMap));

        for (U32 i = 0; i < mChildCount; ++i)
        {
            mChildMap[mChild[i]->getOctant()] = i;
        }

        checkAlive();
    }

    void checkAlive()
    {
        if (getChildCount() == 0 && getElementCount() == 0)
        {
            oct_node* parent = getOctParent();
            if (parent)
            {
                parent->deleteChild(this);
            }
        }
    }

    void deleteChild(oct_node* node)
    {
        for (U32 i = 0; i < getChildCount(); i++)
        {
            if (getChild(i) == node)
            {
                removeChild(i, true);
                return;
            }
        }

        OCT_ERRS << "Octree failed to delete requested child." << LL_ENDL;
    }

protected:
    typedef enum
    {
        CENTER = 0,
        SIZE = 1,
        MAX = 2,
        MIN = 3
    } eDName;

    LLVector4a mCenter;
    LLVector4a mSize;
    LLVector4a mMax;
    LLVector4a mMin;

    oct_node* mParent;
    U8 mOctant;

    oct_node* mChild[8];
    U8 mChildMap[8];
    U32 mChildCount;

    element_list mData;
};

//just like a regular node, except it might expand on insert and compress on balance
template <class T, typename T_PTR>
class LLOctreeRoot : public LLOctreeNode<T, T_PTR>
{
public:
    typedef LLOctreeNode<T, T_PTR> BaseType;
    typedef LLOctreeNode<T, T_PTR> oct_node;

    LLOctreeRoot(const LLVector4a& center,
                 const LLVector4a& size,
                 BaseType* parent)
    :   BaseType(center, size, parent)
    {
    }

    bool balance() override
    {
        //LL_PROFILE_ZONE_NAMED_COLOR("Octree::balance()",OCTREE_DEBUG_COLOR_BALANCE);

        if (this->getChildCount() == 1 &&
            !(this->mChild[0]->isLeaf()) &&
            this->mChild[0]->getElementCount() == 0)
        { //if we have only one child and that child is an empty branch, make that child the root
            oct_node* child = this->mChild[0];

            //make the root node look like the child
            this->setCenter(this->mChild[0]->getCenter());
            this->setSize(this->mChild[0]->getSize());
            this->updateMinMax();

            //reset root node child list
            this->clearChildren();

            //copy the child's children into the root node silently
            //(don't notify listeners of addition)
            for (U32 i = 0; i < child->getChildCount(); i++)
            {
                this->addChild(child->getChild(i), true);
            }

            //destroy child
            child->clearChildren();
            delete child;

            return false;
        }

        return true;
    }

    // LLOctreeRoot::insert
    bool insert(T* data) override
    {
        if (data == nullptr)
        {
            OCT_ERRS << "!!! INVALID ELEMENT ADDED TO OCTREE ROOT !!!" << LL_ENDL;
            return false;
        }

        if (data->getBinRadius() > 4096.0)
        {
            OCT_ERRS << "!!! ELEMENT EXCEEDS MAXIMUM SIZE IN OCTREE ROOT !!!" << LL_ENDL;
            return false;
        }

        LLVector4a MAX_MAG;
        MAX_MAG.splat(1024.f*1024.f);

        const LLVector4a& v = data->getPositionGroup();

        LLVector4a val;
        val.setSub(v, BaseType::mCenter);
        val.setAbs(val);
        S32 lt = val.lessThan(MAX_MAG).getGatheredBits() & 0x7;

        if (lt != 0x7)
        {
            //OCT_ERRS << "!!! ELEMENT EXCEEDS RANGE OF SPATIAL PARTITION !!!" << LL_ENDL;
            return false;
        }

        if (this->getSize()[0] > data->getBinRadius() && this->isInside(data->getPositionGroup()))
        {
            //we got it, just act like a branch
            oct_node* node = this->getNodeAt(data);
            if (node == this)
            {
                oct_node::insert(data);
            }
            else if (node->isInside(data->getPositionGroup()))
            {
                node->insert(data);
            }
            else
            {
                // calling node->insert(data) will return us to root
                OCT_ERRS << "Failed to insert data at child node" << LL_ENDL;
            }
        }
        else if (this->getChildCount() == 0)
        {
            //first object being added, just wrap it up
            while (!(this->getSize()[0] > data->getBinRadius() && this->isInside(data->getPositionGroup())))
            {
                LLVector4a center, size;
                center = this->getCenter();
                size = this->getSize();
                oct_node::pushCenter(center, size, data);
                this->setCenter(center);
                size.mul(2.f);
                this->setSize(size);
                this->updateMinMax();
            }
            oct_node::insert(data);
        }
        else
        {
            while (!(this->getSize()[0] > data->getBinRadius() && this->isInside(data->getPositionGroup())))
            {
                //the data is outside the root node, we need to grow
                LLVector4a center(this->getCenter());
                LLVector4a size(this->getSize());

                //expand this node
                LLVector4a newcenter(center);
                oct_node::pushCenter(newcenter, size, data);
                this->setCenter(newcenter);
                LLVector4a size2 = size;
                size2.mul(2.f);
                this->setSize(size2);
                this->updateMinMax();

                llassert(size[0] >= gOctreeMinSize);

                //copy our children to a new branch
                oct_node* newnode = new oct_node(center, size, this);

                for (U32 i = 0; i < this->getChildCount(); i++)
                {
                    oct_node* child = this->getChild(i);
                    newnode->addChild(child);
                }

                //clear our children and add the root copy
                this->clearChildren();
                this->addChild(newnode);
            }

            //insert the data
            insert(data);
        }

        return false;
    }

    bool isLeaf() const override
    {
        // root can't be a leaf
        return false;
    }
};

//========================
//      LLOctreeTraveler
//========================
template <class T, typename T_PTR>
void LLOctreeTraveler<T, T_PTR>::traverse(const LLOctreeNode<T, T_PTR>* node)
{
    node->accept(this);
    for (U32 i = 0; i < node->getChildCount(); i++)
    {
        traverse(node->getChild(i));
    }
}

template <class T, typename T_PTR>
void LLOctreeTravelerDepthFirst<T, T_PTR>::traverse(const LLOctreeNode<T, T_PTR>* node)
{
    for (U32 i = 0; i < node->getChildCount(); i++)
    {
        traverse(node->getChild(i));
    }
    node->accept(this);
}

#endif