RedCore/cocos2d/cocos/3d/CCTerrain.cpp

/****************************************************************************
Copyright (c) 2015-2017 Chukong Technologies Inc.

http://www.cocos2d-x.org

Permission is hereby granted, free of charge, to any person obtaining a copy
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#include "3d/CCTerrain.h"

USING_NS_CC;
#include <stdlib.h>
#include <float.h>
#include <set>
#include "renderer/CCGLProgram.h"
#include "renderer/CCGLProgramCache.h"
#include "renderer/CCGLProgramState.h"
#include "renderer/CCRenderer.h"
#include "renderer/CCGLProgramStateCache.h"
#include "renderer/ccGLStateCache.h"
#include "renderer/CCRenderState.h"
#include "base/CCDirector.h"
#include "base/CCEventType.h"
#include "2d/CCCamera.h"
#include "platform/CCImage.h"

NS_CC_BEGIN

// check a number is power of two.
static bool isPOT(int number)
{
    bool flag = false;
    if((number>0)&&(number&(number-1))==0)
        flag = true;
    return flag;
}

Terrain * Terrain::create(TerrainData &parameter, CrackFixedType fixedType)
{
    Terrain * terrain = new (std::nothrow)Terrain();
    if (terrain->initWithTerrainData(parameter, fixedType))
    {
        terrain->autorelease();
        return terrain;
    }
    CC_SAFE_DELETE(terrain);
    return terrain;
}
bool Terrain::initWithTerrainData(TerrainData &parameter, CrackFixedType fixedType)
{
    this->setSkirtHeightRatio(parameter._skirtHeightRatio);
    this->_terrainData = parameter;
    this->_crackFixedType = fixedType;
    this->_isCameraViewChanged = true;
    //chunksize
    this->_chunkSize = parameter._chunkSize;
    bool initResult = true;

    //init heightmap
    initResult &= this->initHeightMap(parameter._heightMapSrc);
    //init textures alpha map,detail Maps
    initResult &= this->initTextures();
    initResult &= this->initProperties();

    return initResult;
}

void cocos2d::Terrain::setLightMap(const std::string& fileName)
{
    CC_SAFE_RELEASE(_lightMap);
    auto image = new (std::nothrow)Image();
    image->initWithImageFile(fileName);
    _lightMap = new (std::nothrow)Texture2D();
    _lightMap->initWithImage(image);

    Texture2D::TexParams tRepeatParams;//set texture parameters
    tRepeatParams.magFilter = tRepeatParams.minFilter = GL_LINEAR;
    tRepeatParams.wrapS = GL_REPEAT;
    tRepeatParams.wrapT = GL_REPEAT;
    _lightMap->setTexParameters(tRepeatParams);

}

void cocos2d::Terrain::setLightDir(const Vec3& lightDir)
{
    _lightDir = lightDir;
}

bool Terrain::initProperties()
{
    auto shader = GLProgramCache::getInstance()->getGLProgram(GLProgram::SHADER_3D_TERRAIN);
    auto state = GLProgramState::create(shader);

    setGLProgramState(state);

    _stateBlock->setBlend(false);
    _stateBlock->setDepthWrite(true);
    _stateBlock->setDepthTest(true);
    _stateBlock->setCullFace(true);

    setDrawWire(false);
    setIsEnableFrustumCull(true);
    setAnchorPoint(Vec2(0,0));
    return true;
}

void Terrain::draw(cocos2d::Renderer *renderer, const cocos2d::Mat4 &transform, uint32_t flags)
{
    _customCommand.func = CC_CALLBACK_0(Terrain::onDraw, this, transform, flags);
    renderer->addCommand(&_customCommand);
}

void Terrain::onDraw(const Mat4 &transform, uint32_t /*flags*/)
{
    auto modelMatrix = getNodeToWorldTransform();
    if(memcmp(&modelMatrix,&_terrainModelMatrix,sizeof(Mat4))!=0)
    {
        _terrainModelMatrix = modelMatrix;
        _quadRoot->preCalculateAABB(_terrainModelMatrix);
    }

    auto glProgram = getGLProgram();
    glProgram->use();
#if (CC_TARGET_PLATFORM == CC_PLATFORM_MAC) || (CC_TARGET_PLATFORM == CC_PLATFORM_WIN32) || (CC_TARGET_PLATFORM == CC_PLATFORM_LINUX)
    if(_isDrawWire)
    {
        glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
    }else
    {
        glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
    }
#endif

    _stateBlock->bind();

    GL::enableVertexAttribs(1<<_positionLocation | 1 << _texcoordLocation | 1<<_normalLocation);
    glProgram->setUniformsForBuiltins(transform);
    _glProgramState->applyUniforms();
    glUniform3f(_lightDirLocation,_lightDir.x,_lightDir.y,_lightDir.z);
    if(!_alphaMap)
    {
        GL::bindTexture2D(_detailMapTextures[0]->getName());
        //getGLProgramState()->setUniformTexture("")
        glUniform1i(_detailMapLocation[0],0);
        glUniform1i(_alphaIsHasAlphaMapLocation,0);
    }else
    {
        for(int i =0;i<_maxDetailMapValue;++i)
        {
            GL::bindTexture2DN(i,_detailMapTextures[i]->getName());
            glUniform1i(_detailMapLocation[i],i);

            glUniform1f(_detailMapSizeLocation[i],_terrainData._detailMaps[i]._detailMapSize);
        }

        glUniform1i(_alphaIsHasAlphaMapLocation,1);

        GL::bindTexture2DN(4, _alphaMap->getName());
        glUniform1i(_alphaMapLocation,4);
    }
    if (_lightMap)
    {
        glUniform1i(_lightMapCheckLocation, 1);
        GL::bindTexture2DN(5, _lightMap->getName());
        glUniform1i(_lightMapLocation, 5);
    }else
    {
        glUniform1i(_lightMapCheckLocation, 0);
    }
    auto camera = Camera::getVisitingCamera();

    if(memcmp(&_CameraMatrix,&camera->getViewMatrix(),sizeof(Mat4))!=0)
    {
        _isCameraViewChanged = true;
        _CameraMatrix = camera->getViewMatrix();
    }


    if(_isCameraViewChanged )
    {
        auto m = camera->getNodeToWorldTransform();
        //set lod
        setChunksLOD(Vec3(m.m[12], m.m[13], m.m[14]));
    }

    if(_isCameraViewChanged )
    {
        _quadRoot->resetNeedDraw(true);//reset it
        //camera frustum culling
        if (_isEnableFrustumCull)
        {
            _quadRoot->cullByCamera(camera, _terrainModelMatrix);
        }
    }
    _quadRoot->draw();
    if(_isCameraViewChanged)
    {
        _isCameraViewChanged = false;
    }
    glActiveTexture(GL_TEXTURE0);

#if (CC_TARGET_PLATFORM == CC_PLATFORM_MAC) || (CC_TARGET_PLATFORM == CC_PLATFORM_WIN32) || (CC_TARGET_PLATFORM == CC_PLATFORM_LINUX)
    if(_isDrawWire)//reset state.
    {
        glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
    }
#endif
}

bool Terrain::initHeightMap(const std::string& heightMap)
{
    _heightMapImage = new (std::nothrow) Image();
    _heightMapImage->initWithImageFile(heightMap);
    _data = _heightMapImage->getData();
    _imageWidth =_heightMapImage->getWidth();
    _imageHeight =_heightMapImage->getHeight();

    //only the image size  is the Powers Of Two(POT) or POT+1
    if((isPOT(_imageWidth) &&isPOT(_imageHeight)) || (isPOT(_imageWidth-1) &&isPOT(_imageHeight -1)))
    {
        int chunk_amount_y = _imageHeight/_chunkSize.height;
        int chunk_amount_x = _imageWidth/_chunkSize.width;
        loadVertices();
        calculateNormal();
        memset(_chunkesArray, 0, sizeof(_chunkesArray));

        for(int m =0;m<chunk_amount_y;m++)
        {
            for(int n =0; n<chunk_amount_x;n++)
            {
                _chunkesArray[m][n] = new (std::nothrow) Chunk();
                _chunkesArray[m][n]->_terrain = this;
                _chunkesArray[m][n]->_size = _chunkSize;
                _chunkesArray[m][n]->generate(_imageWidth,_imageHeight,m,n,_data);
            }
        }

        //calculate the neighbor
        for(int m =0;m<chunk_amount_y;m++)
        {
            for(int n =0; n<chunk_amount_x;n++)
            {
                if(n-1>=0) _chunkesArray[m][n]->_left = _chunkesArray[m][n-1];
                if(n+1<chunk_amount_x) _chunkesArray[m][n]->_right = _chunkesArray[m][n+1];
                if(m-1>=0) _chunkesArray[m][n]->_back = _chunkesArray[m-1][n];
                if(m+1<chunk_amount_y) _chunkesArray[m][n]->_front = _chunkesArray[m+1][n];
            }
        }
        _quadRoot = new (std::nothrow) QuadTree(0,0,_imageWidth,_imageHeight,this);
        setLODDistance(_chunkSize.width,2*_chunkSize.width,3*_chunkSize.width);
        return true;
    }else
    {
        CCLOG("warning: the height map size is not POT or POT + 1");
        return false;
    }
}

Terrain::Terrain()
: _alphaMap(nullptr)
, _stateBlock(nullptr)
, _lightMap(nullptr)
, _lightDir(-1.f, -1.f, 0.f)
{
    _stateBlock = RenderState::StateBlock::create();
    CC_SAFE_RETAIN(_stateBlock);

    _customCommand.setTransparent(false);
    _customCommand.set3D(true);
#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID || CC_TARGET_PLATFORM == CC_PLATFORM_WINRT)
    auto _backToForegroundListener = EventListenerCustom::create(EVENT_RENDERER_RECREATED,
        [this](EventCustom*)
    {
        reload();
    }
    );
    Director::getInstance()->getEventDispatcher()->addEventListenerWithFixedPriority(_backToForegroundListener, 1);
#endif
}

void Terrain::setChunksLOD(const Vec3& cameraPos)
{
    int chunk_amount_y = _imageHeight/_chunkSize.height;
    int chunk_amount_x = _imageWidth/_chunkSize.width;
    for(int m=0;m<chunk_amount_y;m++)
        for(int n =0;n<chunk_amount_x;n++)
        {
            AABB aabb = _chunkesArray[m][n]->_parent->_worldSpaceAABB;
            auto center = aabb.getCenter();
            float dist = Vec2(center.x, center.z).distance(Vec2(cameraPos.x, cameraPos.z));
            _chunkesArray[m][n]->_currentLod = 3;
            for(int i =0;i<3;++i)
            {
                if(dist<=_lodDistance[i])
                {
                    _chunkesArray[m][n]->_currentLod = i;
                    break;
                }
            }
        }
}

float Terrain::getHeight(float x, float z, Vec3 * normal) const
{
    Vec2 pos(x,z);

    //top-left
    Vec2 tl(-1*_terrainData._mapScale*_imageWidth/2,-1*_terrainData._mapScale*_imageHeight/2);
    auto mulResult = getNodeToWorldTransform() * Vec4(tl.x, 0.0f, tl.y, 1.0f);
    tl.set(mulResult.x, mulResult.z);

    Vec2 to_tl = pos - tl;

    //real size
    Vec2 size(_imageWidth*_terrainData._mapScale,_imageHeight*_terrainData._mapScale);
    mulResult = getNodeToWorldTransform() * Vec4(size.x, 0.0f, size.y, 0.0f);
    size.set(mulResult.x, mulResult.z);

    float width_ratio = to_tl.x/size.x;
    float height_ratio = to_tl.y/size.y;

    float image_x = width_ratio * _imageWidth;
    float image_y = height_ratio * _imageHeight;
    float u =image_x - (int)image_x;
    float v =image_y - (int)image_y;
    float i = (int)image_x;
    float j = (int)image_y;


    if(image_x>=_imageWidth-1 || image_y >=_imageHeight-1 || image_x<0 || image_y<0)
    {
        if (normal)
        {
            normal->setZero();
        }
        return 0;
    }else
    {
        float a = getImageHeight(i,j)*getScaleY();
        float b = getImageHeight(i,j+1)*getScaleY();
        float c = getImageHeight(i+1,j)*getScaleY();
        float d = getImageHeight(i+1,j+1)*getScaleY();
        if(normal)
        {
            normal->x = c - b;
            normal->y = 2;
            normal->z = d - a;
            normal->normalize();
            //(*normal) = (1-u)*(1-v)*getNormal(i,j)+ (1-u)*v*getNormal(i,j+1) + u*(1-v)*getNormal(i+1,j)+ u*v*getNormal(i+1,j+1);
        }
        float result = (1-u)*(1-v)*getImageHeight(i,j)*getScaleY() + (1-u)*v*getImageHeight(i,j+1)*getScaleY() + u*(1-v)*getImageHeight(i+1,j)*getScaleY() + u*v*getImageHeight(i+1,j+1)*getScaleY();
        return result;
    }
}

float Terrain::getHeight(const Vec2& pos, Vec3* normal) const
{
    return getHeight(pos.x, pos.y, normal);
}

float Terrain::getImageHeight(int pixel_x,int pixel_y) const
{
    int byte_stride =1;
    switch (_heightMapImage->getRenderFormat())
    {
    case Texture2D::PixelFormat::BGRA8888:
        byte_stride = 4;
        break;
    case  Texture2D::PixelFormat::RGB888:
        byte_stride =3;
        break;
    case Texture2D::PixelFormat::I8:
        byte_stride =1;
        break;
    default:
        break;
    }
    return _data[(pixel_y*_imageWidth+pixel_x)*byte_stride]*1.0/255*_terrainData._mapHeight -0.5*_terrainData._mapHeight;
}

void Terrain::loadVertices()
{
    _maxHeight = -99999;
    _minHeight = 99999;
    for(int i =0;i<_imageHeight;++i)
    {
        for(int j =0;j<_imageWidth;j++)
        {
            float height = getImageHeight(j,i);
            TerrainVertexData v;
            v._position = Vec3(j*_terrainData._mapScale- _imageWidth/2*_terrainData._mapScale, //x
                height, //y
                i*_terrainData._mapScale - _imageHeight/2*_terrainData._mapScale);//z
            v._texcoord = Tex2F(j*1.0/_imageWidth,i*1.0/_imageHeight);
            _vertices.push_back (v);

            //update the min & max height;
            if(height>_maxHeight) _maxHeight = height;
            if(height<_minHeight) _minHeight = height;
        }
    }
}

void Terrain::calculateNormal()
{
    _indices.clear();
    //we generate whole terrain indices(global indices) for correct normal calculate
    for(int i =0;i<_imageHeight-1;i+=1)
    {
        for(int j = 0;j<_imageWidth-1;j+=1)
        {

            int nLocIndex = i * _imageWidth + j;
            _indices.push_back (nLocIndex);
            _indices.push_back (nLocIndex + _imageWidth);
            _indices.push_back (nLocIndex + 1);

            _indices.push_back (nLocIndex + 1);
            _indices.push_back (nLocIndex + _imageWidth);
            _indices.push_back (nLocIndex + _imageWidth+1);
        }
    }
    for (size_t i = 0, size = _indices.size(); i < size; i += 3) {
        unsigned int Index0 = _indices[i];
        unsigned int Index1 = _indices[i + 1];
        unsigned int Index2 = _indices[i + 2];
        Vec3 v1 = _vertices[Index1]._position - _vertices[Index0]._position;
        Vec3 v2 = _vertices[Index2]._position - _vertices[Index0]._position;
        Vec3 Normal;
        Vec3::cross(v1,v2,&Normal);
        Normal.normalize();
        _vertices[Index0]._normal += Normal;
        _vertices[Index1]._normal += Normal;
        _vertices[Index2]._normal += Normal;
    }

    for (auto &vertex : _vertices) {
        vertex._normal.normalize();
    }
    //global indices no need at all
    _indices.clear();
}

void Terrain::setDrawWire(bool bool_value)
{
    _isDrawWire = bool_value;
}

void Terrain::setLODDistance(float lod_1, float lod_2, float lod_3)
{
    _lodDistance[0] = lod_1;
    _lodDistance[1] = lod_2;
    _lodDistance[2] = lod_3;
}

void Terrain::setIsEnableFrustumCull(bool bool_value)
{
    _isEnableFrustumCull = bool_value;
}

Terrain::~Terrain()
{
    CC_SAFE_RELEASE(_stateBlock);
    CC_SAFE_RELEASE(_alphaMap);
    CC_SAFE_RELEASE(_lightMap);
    CC_SAFE_RELEASE(_heightMapImage);
    delete _quadRoot;
    for(int i=0;i<4;++i)
    {
        if(_detailMapTextures[i])
        {
            _detailMapTextures[i]->release();
        }
    }
    for(int i = 0;i<MAX_CHUNKES;++i)
    {
        for(int j = 0;j<MAX_CHUNKES;j++)
        {
            if(_chunkesArray[i][j])
            {
                delete _chunkesArray[i][j];
            }
        }
    }

    for(size_t i =0, size = _chunkLodIndicesSet.size(); i < size; ++i)
    {
        glDeleteBuffers(1,&(_chunkLodIndicesSet[i]._chunkIndices._indices));
    }

    for(size_t i =0, size = _chunkLodIndicesSkirtSet.size(); i < size; ++i)
    {
        glDeleteBuffers(1,&(_chunkLodIndicesSkirtSet[i]._chunkIndices._indices));
    }

#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID || CC_TARGET_PLATFORM == CC_PLATFORM_WINRT)
    Director::getInstance()->getEventDispatcher()->removeEventListener(_backToForegroundListener);
#endif
}

cocos2d::Vec3 Terrain::getNormal(int pixel_x, int pixel_y) const
{
    float a = getImageHeight(pixel_x,pixel_y)*getScaleY();
    float b = getImageHeight(pixel_x,pixel_y+1)*getScaleY();
    float c = getImageHeight(pixel_x+1,pixel_y)*getScaleY();
    float d = getImageHeight(pixel_x+1,pixel_y+1)*getScaleY();
    Vec3 normal;
    normal.x = c - b;
    normal.y = 2;
    normal.z = d - a;
    normal.normalize();
    return normal;
}

cocos2d::Vec3 Terrain::getIntersectionPoint(const Ray & ray) const
{
    Vec3 collisionPoint;
    if (getIntersectionPoint(ray, collisionPoint))
    {
        return collisionPoint;
    }
    else
    {
        return Vec3(0,0,0);
    }
}

bool Terrain::getIntersectionPoint(const Ray & ray_, Vec3 & intersectionPoint) const
{
    // convert ray from world space to local space
    Ray ray(ray_);
    getWorldToNodeTransform().transformPoint(&(ray._origin));

    std::set<Chunk *> closeList;
    Vec2 start = Vec2(ray_._origin.x,ray_._origin.z);
    Vec2 dir = Vec2(ray._direction.x,ray._direction.z);
    start = convertToTerrainSpace(start);
    start.x /=(_terrainData._chunkSize.width+1);
    start.y /=(_terrainData._chunkSize.height+1);
    Vec2 delta = dir.getNormalized();
    auto width = float(_imageWidth) / (_terrainData._chunkSize.width + 1);
    auto height = float(_imageHeight) / (_terrainData._chunkSize.height + 1);
    bool hasIntersect = false;
    float intersectionDist = FLT_MAX;
    Vec3 tmpIntersectionPoint;
    for(;;)
    {
        int x1 = floorf(start.x);
        int x2 = ceilf(start.x);
        int y1 = floorf(start.y);
        int y2 = ceilf(start.y);
        for (int x = x1; x <= x2; x++) {
            for (int y = y1; y <= y2; y++) {
                auto chunk = getChunkByIndex(x, y);
                if (chunk)
                {
                    if (closeList.find(chunk) == closeList.end())
                    {
                        if (chunk->getIntersectPointWithRay(ray, tmpIntersectionPoint))
                        {
                            float dist = (ray._origin - tmpIntersectionPoint).length();
                            if (intersectionDist > dist)
                            {
                                hasIntersect = true;
                                intersectionDist = dist;
                                intersectionPoint = tmpIntersectionPoint;
                            }
                        }
                        closeList.insert(chunk);
                    }
                }
            }
        }
        if ((delta.x > 0 && start.x > width) || (delta.x <0 && start.x <0))
        {
            break;
        }
        if ((delta.y > 0 && start.y > height) || (delta.y < 0 && start.y < 0))
        {
            break;
        }
        start.x += delta.x;
        start.y += delta.y;
    }
    return hasIntersect;
}

void Terrain::setMaxDetailMapAmount(int max_value)
{
    _maxDetailMapValue = max_value;
}

cocos2d::Vec2 Terrain::convertToTerrainSpace(const Vec2& worldSpaceXZ) const
{
    Vec2 pos(worldSpaceXZ.x,worldSpaceXZ.y);

    //top-left
    Vec2 tl(-1*_terrainData._mapScale*_imageWidth/2,-1*_terrainData._mapScale*_imageHeight/2);
    auto result  = getNodeToWorldTransform()*Vec4(tl.x,0.0f,tl.y,1.0f);
    tl.set(result.x, result.z);

    Vec2 to_tl = pos - tl;

    //real size
    Vec2 size(_imageWidth*_terrainData._mapScale,_imageHeight*_terrainData._mapScale);
    result = getNodeToWorldTransform()*Vec4(size.x,0.0f,size.y,0.0f);
    size.set(result.x, result.z);

    float width_ratio = to_tl.x/size.x;
    float height_ratio = to_tl.y/size.y;

    float image_x = width_ratio * _imageWidth;
    float image_y = height_ratio * _imageHeight;
    return Vec2(image_x,image_y);
}

void Terrain::resetHeightMap(const std::string& heightMap)
{
    _heightMapImage->release();
    _vertices.clear();
    free(_data);
    for(int i = 0;i<MAX_CHUNKES;++i)
    {
        for(int j = 0;j<MAX_CHUNKES;j++)
        {
            if(_chunkesArray[i][j])
            {
                delete _chunkesArray[i][j];
            }
        }
    }
    delete _quadRoot;
    initHeightMap(heightMap);
}

float Terrain::getMinHeight()
{
    return _minHeight;
}

float Terrain::getMaxHeight()
{
    return _maxHeight;
}

cocos2d::AABB Terrain::getAABB()
{
    return _quadRoot->_worldSpaceAABB;
}

Terrain::QuadTree * Terrain::getQuadTree()
{
    return _quadRoot;
}


std::vector<float> Terrain::getHeightData() const
{
    std::vector<float> data;
    data.resize(_imageWidth * _imageHeight);
    for (int i = 0; i < _imageHeight; ++i) {
        for (int j = 0; j < _imageWidth; j++) {
            int idx = i * _imageWidth + j;
            data[idx] = (_vertices[idx]._position.y);
        }
    }
    return data;
}

Terrain::Chunk * cocos2d::Terrain::getChunkByIndex(int x, int y) const
{
    if (x<0 || y<0 || x>= MAX_CHUNKES || y >= MAX_CHUNKES) return nullptr;
    return _chunkesArray[y][x];
}

void Terrain::setAlphaMap(cocos2d::Texture2D * newAlphaMapTexture)
{
    CC_SAFE_RETAIN(newAlphaMapTexture);
    CC_SAFE_RELEASE(_alphaMap);
    _alphaMap = newAlphaMapTexture;
}

void Terrain::setDetailMap(unsigned int index, DetailMap detailMap)
{
    if(index>4)
    {
        CCLOG("invalid DetailMap index %d\n",index);
    }
    _terrainData._detailMaps[index] = detailMap;
    if(_detailMapTextures[index])
    {

        _detailMapTextures[index]->release();
    }
    _detailMapTextures[index] = new (std::nothrow)Texture2D();
    auto textImage = new (std::nothrow)Image();
    textImage->initWithImageFile(detailMap._detailMapSrc);
    _detailMapTextures[index]->initWithImage(textImage);
    delete textImage;
}

Terrain::ChunkIndices Terrain::lookForIndicesLOD(int neighborLod[4], int selfLod, bool * result)
{
    (* result) =false;
    ChunkIndices tmp;
    tmp._indices = 0;
    tmp._size = 0;
    if(_chunkLodIndicesSet.empty())
    {
        (* result) =false;
        return tmp;
    }else
    {
        int test[5];
        memcpy(test,neighborLod,sizeof(int [4]));
        test[4] = selfLod;
        for(size_t i =0, size = _chunkLodIndicesSet.size(); i < size; ++i)
        {
            if(memcmp(test,_chunkLodIndicesSet[i]._relativeLod,sizeof(test))==0)
            {
                (*result) = true;
                return _chunkLodIndicesSet[i]._chunkIndices;
            }
        }
    }
    (* result) =false;
    return tmp;
}

Terrain::ChunkIndices Terrain::insertIndicesLOD(int neighborLod[4], int selfLod, GLushort * indices,int size)
{
    ChunkLODIndices lodIndices;
    memcpy(lodIndices._relativeLod,neighborLod,sizeof(int [4]));
    lodIndices._relativeLod[4] = selfLod;
    lodIndices._chunkIndices._size = size;
    glGenBuffers(1,&(lodIndices._chunkIndices._indices));
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, lodIndices._chunkIndices._indices);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(GLushort)*size,indices,GL_STATIC_DRAW);
    this->_chunkLodIndicesSet.push_back(lodIndices);
    return lodIndices._chunkIndices;
}

Terrain::ChunkIndices Terrain::lookForIndicesLODSkrit(int selfLod, bool * result)
{
    ChunkIndices badResult;
    badResult._indices = 0;
    badResult._size = 0;
    if(this->_chunkLodIndicesSkirtSet.empty())
    {
    (*result) = false;
    return badResult;
    }
    for(size_t i = 0, size = _chunkLodIndicesSkirtSet.size(); i < size; ++i)
    {
        if(_chunkLodIndicesSkirtSet[i]._selfLod == selfLod)
        {
            (*result) = true;
            return _chunkLodIndicesSkirtSet[i]._chunkIndices;
        }
    }
    (*result) = false;
    return badResult;
}

Terrain::ChunkIndices Terrain::insertIndicesLODSkirt(int selfLod, GLushort * indices, int size)
{
    ChunkLODIndicesSkirt skirtIndices;
    skirtIndices._selfLod = selfLod;
    skirtIndices._chunkIndices._size = size;
    glGenBuffers(1,&(skirtIndices._chunkIndices._indices));
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, skirtIndices._chunkIndices._indices);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(GLushort)*size,indices,GL_STATIC_DRAW);
    this->_chunkLodIndicesSkirtSet.push_back(skirtIndices);
    return skirtIndices._chunkIndices;
}

void Terrain::setSkirtHeightRatio(float ratio)
{
    _skirtRatio = ratio;
}

void Terrain::onEnter()
{
#if CC_ENABLE_SCRIPT_BINDING
    if (_scriptType == kScriptTypeJavascript)
    {
        if (ScriptEngineManager::sendNodeEventToJSExtended(this, kNodeOnEnter))
            return;
    }
#endif

    Node::onEnter();
    _terrainModelMatrix = getNodeToWorldTransform();
    _quadRoot->preCalculateAABB(_terrainModelMatrix);
    cacheUniformAttribLocation();
}

void Terrain::cacheUniformAttribLocation()
{

    _positionLocation = glGetAttribLocation(this->getGLProgram()->getProgram(),"a_position");
    _texcoordLocation = glGetAttribLocation(this->getGLProgram()->getProgram(),"a_texCoord");
    _normalLocation = glGetAttribLocation(this->getGLProgram()->getProgram(),"a_normal");
    _alphaMapLocation = -1;
    for(int i =0;i<4;++i)
    {
        _detailMapLocation[i] = -1;
        _detailMapSizeLocation[i] = -1;
    }
    auto glProgram = getGLProgram();
    _alphaIsHasAlphaMapLocation = glGetUniformLocation(glProgram->getProgram(),"u_has_alpha");
    _lightMapCheckLocation = glGetUniformLocation(glProgram->getProgram(), "u_has_light_map");
    if(!_alphaMap)
    {
        _detailMapLocation[0] = glGetUniformLocation(glProgram->getProgram(),"u_texture0");
    }else
    {
        for(int i =0;i<_maxDetailMapValue;++i)
        {
            char str[20];
            sprintf(str,"u_texture%d",i);
            _detailMapLocation[i] = glGetUniformLocation(glProgram->getProgram(),str);

            sprintf(str,"u_detailSize[%d]",i);
            _detailMapSizeLocation[i] = glGetUniformLocation(glProgram->getProgram(),str);
        }
        _alphaMapLocation = glGetUniformLocation(glProgram->getProgram(),"u_alphaMap");
    }
    _lightMapLocation = glGetUniformLocation(glProgram->getProgram(),"u_lightMap");
    _lightDirLocation = glGetUniformLocation(glProgram->getProgram(),"u_lightDir");
}

bool Terrain::initTextures()
{
    for (int i = 0; i < 4; ++i)
    {
        _detailMapTextures[i] = nullptr;
    }

    Texture2D::TexParams texParam;
    texParam.wrapS = GL_REPEAT;
    texParam.wrapT = GL_REPEAT;
    if(_terrainData._alphaMapSrc.empty())
    {
        auto textImage = new (std::nothrow)Image();
        textImage->initWithImageFile(_terrainData._detailMaps[0]._detailMapSrc);
        auto texture = new (std::nothrow)Texture2D();
        texture->initWithImage(textImage);
        texture->generateMipmap();
        _detailMapTextures[0] = texture;
        texParam.minFilter = GL_LINEAR_MIPMAP_LINEAR;
        texParam.magFilter = GL_LINEAR;
        texture->setTexParameters(texParam);
        delete textImage;
    }else
    {
        //alpha map
        auto image = new (std::nothrow)Image();
        image->initWithImageFile(_terrainData._alphaMapSrc);
        _alphaMap = new (std::nothrow)Texture2D();
        _alphaMap->initWithImage(image);
        texParam.wrapS = GL_CLAMP_TO_EDGE;
        texParam.wrapT = GL_CLAMP_TO_EDGE;
        texParam.minFilter = GL_LINEAR;
        texParam.magFilter = GL_LINEAR;
        _alphaMap->setTexParameters(texParam);
        delete image;

        for(int i =0;i<_terrainData._detailMapAmount;++i)
        {
            auto textImage = new (std::nothrow)Image();
            textImage->initWithImageFile(_terrainData._detailMaps[i]._detailMapSrc);
            auto texture = new (std::nothrow)Texture2D();
            texture->initWithImage(textImage);
            delete textImage;
            texture->generateMipmap();
            _detailMapTextures[i] = texture;

            texParam.wrapS = GL_REPEAT;
            texParam.wrapT = GL_REPEAT;
            texParam.minFilter = GL_LINEAR_MIPMAP_LINEAR;
            texParam.magFilter = GL_LINEAR;
            texture->setTexParameters(texParam);
        }
    }
    setMaxDetailMapAmount(_terrainData._detailMapAmount);
    return true;
}

void Terrain::reload()
{
    int chunk_amount_y = _imageHeight/_chunkSize.height;
    int chunk_amount_x = _imageWidth/_chunkSize.width;

    for(int m =0;m<chunk_amount_y;m++)
    {
        for(int n =0; n<chunk_amount_x;n++)
        {
            _chunkesArray[m][n]->finish();
        }
    }

    initTextures();
    _chunkLodIndicesSet.clear();
    _chunkLodIndicesSkirtSet.clear();
}

void Terrain::Chunk::finish()
{
    //generate two VBO ,the first for vertices, we just setup datas once ,won't changed at all
    //the second vbo for the indices, because we use level of detail technique to each chunk, so we will modified frequently
    glGenBuffers(1,&_vbo);

    //only set for vertices vbo
    glBindBuffer(GL_ARRAY_BUFFER, _vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(TerrainVertexData)*_originalVertices.size(), &_originalVertices[0], GL_STREAM_DRAW);

    glBindBuffer(GL_ARRAY_BUFFER,0);

    calculateSlope();

    for(int i =0;i<4;++i)
    {
        int step = 1<<_currentLod;
        //reserve the indices size, the first part is the core part of the chunk, the second part & third part is for fix crack
        int indicesAmount =(_terrain->_chunkSize.width/step+1)*(_terrain->_chunkSize.height/step+1)*6+(_terrain->_chunkSize.height/step)*6
            +(_terrain->_chunkSize.width/step)*6;
        _lod[i]._indices.reserve(indicesAmount);
    }
    _oldLod = -1;
}

void Terrain::Chunk::bindAndDraw()
{
    glBindBuffer(GL_ARRAY_BUFFER, _vbo);
    if(_terrain->_isCameraViewChanged || _oldLod <0)
    {
        switch (_terrain->_crackFixedType)
        {
        case CrackFixedType::SKIRT:

            updateIndicesLODSkirt();
            break;
        case CrackFixedType::INCREASE_LOWER:
            updateVerticesForLOD();
            updateIndicesLOD();
            break;
        default:
            break;
        }
    }
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,_chunkIndices._indices);
    unsigned long offset = 0;
    //position
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 3, GL_FLOAT, GL_FALSE, sizeof(TerrainVertexData), (GLvoid *)offset);
    offset +=sizeof(Vec3);
    //texcoord
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_TEX_COORD,2,GL_FLOAT,GL_FALSE,sizeof(TerrainVertexData),(GLvoid *)offset);
    offset +=sizeof(Tex2F);
    //normal
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_NORMAL,3,GL_FLOAT,GL_FALSE,sizeof(TerrainVertexData),(GLvoid *)offset);
    glDrawElements(GL_TRIANGLES, (GLsizei)_chunkIndices._size, GL_UNSIGNED_SHORT, 0);
    CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, _chunkIndices._size);
}

void Terrain::Chunk::generate(int imgWidth, int imageHei, int m, int n, const unsigned char * /*data*/)
{
    _posY = m;
    _posX = n;
    switch (_terrain->_crackFixedType)
    {
    case CrackFixedType::SKIRT:
        {
            for(int i=_size.height*m;i<=_size.height*(m+1);++i)
            {
                if(i>=imageHei) break;
                for(int j=_size.width*n;j<=_size.width*(n+1);j++)
                {
                    if(j>=imgWidth)break;
                    auto v =_terrain->_vertices[i*imgWidth + j];
                    _originalVertices.push_back (v);
                }
            }
            // add four skirts

            float skirtHeight =  _terrain->_skirtRatio *_terrain->_terrainData._mapScale*8;
            //#1
            _terrain->_skirtVerticesOffset[0] = (int)_originalVertices.size();
            for(int i =_size.height*m;i<=_size.height*(m+1);++i)
            {
                auto v = _terrain->_vertices[i*imgWidth +_size.width*(n+1)];
                v._position.y -= skirtHeight;
                _originalVertices.push_back (v);
            }

            //#2
            _terrain->_skirtVerticesOffset[1] = (int)_originalVertices.size();
            for(int j =_size.width*n;j<=_size.width*(n+1);j++)
            {
                auto v = _terrain->_vertices[_size.height*(m+1)*imgWidth + j];
                v._position.y -=skirtHeight;
                _originalVertices.push_back (v);
            }

            //#3
            _terrain->_skirtVerticesOffset[2] = (int)_originalVertices.size();
            for(int i =_size.height*m;i<=_size.height*(m+1);++i)
            {
                auto v = _terrain->_vertices[i*imgWidth + _size.width*n];
                v._position.y -= skirtHeight;
                _originalVertices.push_back (v);
            }

            //#4
            _terrain->_skirtVerticesOffset[3] = (int)_originalVertices.size();
            for(int j =_size.width*n;j<=_size.width*(n+1);j++)
            {
                auto v = _terrain->_vertices[_size.height*m*imgWidth+j];
                v._position.y -= skirtHeight;
                //v.position.y = -5;
                _originalVertices.push_back (v);
            }
        }
        break;
    case CrackFixedType::INCREASE_LOWER:
        {
            for(int i=_size.height*m;i<=_size.height*(m+1);++i)
            {
                if(i>=imageHei) break;
                for(int j=_size.width*n;j<=_size.width*(n+1);j++)
                {
                    if(j>=imgWidth)break;
                    auto v =_terrain->_vertices[i*imgWidth + j];
                    _originalVertices.push_back (v);
                }
            }
        }
        break;
    }
    //store triangle:
    for (int i = 0; i < _size.height; ++i)
    {
        for (int j = 0; j < _size.width; j++)
        {
             int nLocIndex = i * (_size.width + 1) + j;
             Triangle a(_originalVertices[nLocIndex]._position, _originalVertices[nLocIndex + 1 * (_size.width + 1)]._position, _originalVertices[nLocIndex + 1]._position);
             Triangle b(_originalVertices[nLocIndex + 1]._position, _originalVertices[nLocIndex + 1 * (_size.width + 1)]._position, _originalVertices[nLocIndex + 1 * (_size.width + 1) + 1]._position);

            _trianglesList.push_back(a);
            _trianglesList.push_back(b);
        }
    }

    calculateAABB();
    finish();
}

Terrain::Chunk::Chunk()
{
    _currentLod = 0;
    _left = nullptr;
    _right = nullptr;
    _back = nullptr;
    _front = nullptr;
    _oldLod = -1;
    for(int i =0;i<4;++i)
    {
        _neighborOldLOD[i] = -1;
    }
}

void Terrain::Chunk::updateIndicesLOD()
{
    int currentNeighborLOD[4];
    if(_left)
    {
        currentNeighborLOD[0] = _left->_currentLod;
    }else{currentNeighborLOD[0] = -1;}
    if(_right)
    {
        currentNeighborLOD[1] = _right->_currentLod;
    }else{currentNeighborLOD[1] = -1;}
    if(_back)
    {
        currentNeighborLOD[2] = _back->_currentLod;
    }else{currentNeighborLOD[2] = -1;}
    if(_front)
    {
        currentNeighborLOD[3] = _front->_currentLod;
    }else{currentNeighborLOD[3] = -1;}

    if(_oldLod == _currentLod &&(memcmp(currentNeighborLOD,_neighborOldLOD,sizeof(currentNeighborLOD))==0) )
    {
        return;// no need to update
    }
    bool isOk;
    _chunkIndices = _terrain->lookForIndicesLOD(currentNeighborLOD,_currentLod,&isOk);
    if(isOk)
    {
        return;
    }
    memcpy(_neighborOldLOD,currentNeighborLOD,sizeof(currentNeighborLOD));
    _oldLod = _currentLod;
    int gridY = _size.height;
    int gridX = _size.width;

    int step = 1<<_currentLod;
    if((_left&&_left->_currentLod > _currentLod) ||(_right&&_right->_currentLod > _currentLod)
        ||(_back&&_back->_currentLod > _currentLod) || (_front && _front->_currentLod > _currentLod))
        //need update indices.
    {
        //t-junction inner
        _lod[_currentLod]._indices.clear();
        for(int i =step;i<gridY-step;i+=step)
        {
            for(int j = step;j<gridX-step;j+=step)
            {
                int nLocIndex = i * (gridX+1) + j;
                _lod[_currentLod]._indices.push_back (nLocIndex);
                _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1));
                _lod[_currentLod]._indices.push_back (nLocIndex + step);

                _lod[_currentLod]._indices.push_back (nLocIndex + step);
                _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1));
                _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1) + step);
            }
        }
        //fix T-crack
        int next_step = 1<<(_currentLod+1);
        if(_left&&_left->_currentLod > _currentLod)//left
        {
            for(int i =0;i<gridY;i+=next_step)
            {
                _lod[_currentLod]._indices.push_back(i*(gridX+1)+step);
                _lod[_currentLod]._indices.push_back(i*(gridX+1));
                _lod[_currentLod]._indices.push_back((i+next_step)*(gridX+1));

                _lod[_currentLod]._indices.push_back(i*(gridX+1)+step);
                _lod[_currentLod]._indices.push_back((i+next_step)*(gridX+1));
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1)+step);

                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1)+step);
                _lod[_currentLod]._indices.push_back((i+next_step)*(gridX+1));
                _lod[_currentLod]._indices.push_back((i+next_step)*(gridX+1)+step);
            }
        }else{
            int start=0;
            int end =gridY;
            if(_front&&_front->_currentLod > _currentLod) end -=step;
            if(_back&&_back->_currentLod > _currentLod) start +=step;
            for(int i =start;i<end;i+=step)
            {
                _lod[_currentLod]._indices.push_back(i*(gridX+1)+step);
                _lod[_currentLod]._indices.push_back(i*(gridX+1));
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1));

                _lod[_currentLod]._indices.push_back(i*(gridX+1)+step);
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1));
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1)+step);
            }
        }

        if(_right&&_right->_currentLod > _currentLod)//LEFT
        {
            for(int i =0;i<gridY;i+=next_step)
            {
                _lod[_currentLod]._indices.push_back(i*(gridX+1)+gridX);
                _lod[_currentLod]._indices.push_back(i*(gridX+1)+gridX-step);
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1)+gridX-step);

                _lod[_currentLod]._indices.push_back(i*(gridX+1)+gridX);
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1)+gridX-step);
                _lod[_currentLod]._indices.push_back((i+next_step)*(gridX+1)+gridX-step);

                _lod[_currentLod]._indices.push_back(i*(gridX+1)+gridX);
                _lod[_currentLod]._indices.push_back((i+next_step)*(gridX+1)+gridX-step);
                _lod[_currentLod]._indices.push_back((i+next_step)*(gridX+1)+gridX);
            }
        }else{
            int start=0;
            int end =gridY;
            if(_front&&_front->_currentLod > _currentLod) end -=step;
            if(_back&&_back->_currentLod > _currentLod) start +=step;
            for(int i =start;i<end;i+=step)
            {
                _lod[_currentLod]._indices.push_back(i*(gridX+1)+gridX);
                _lod[_currentLod]._indices.push_back(i*(gridX+1)+gridX-step);
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1)+gridX-step);

                _lod[_currentLod]._indices.push_back(i*(gridX+1)+gridX);
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1)+gridX-step);
                _lod[_currentLod]._indices.push_back((i+step)*(gridX+1)+gridX);
            }
        }
        if(_front&&_front->_currentLod > _currentLod)//front
        {
            for(int i =0;i<gridX;i+=next_step)
            {
                _lod[_currentLod]._indices.push_back((gridY-step)*(gridX+1)+i);
                _lod[_currentLod]._indices.push_back(gridY*(gridX+1)+i);
                _lod[_currentLod]._indices.push_back((gridY-step)*(gridX+1)+i+step);

                _lod[_currentLod]._indices.push_back((gridY-step)*(gridX+1)+i+step);
                _lod[_currentLod]._indices.push_back(gridY*(gridX+1)+i);
                _lod[_currentLod]._indices.push_back(gridY*(gridX+1)+i+next_step);

                _lod[_currentLod]._indices.push_back((gridY-step)*(gridX+1)+i+step);
                _lod[_currentLod]._indices.push_back(gridY*(gridX+1)+i+next_step);
                _lod[_currentLod]._indices.push_back((gridY-step)*(gridX+1)+i+next_step);
            }
        }else
        {
            for(int i =step;i<gridX-step;i+=step)
            {
                _lod[_currentLod]._indices.push_back((gridY-step)*(gridX+1)+i);
                _lod[_currentLod]._indices.push_back(gridY*(gridX+1)+i);
                _lod[_currentLod]._indices.push_back((gridY-step)*(gridX+1)+i+step);

                _lod[_currentLod]._indices.push_back((gridY-step)*(gridX+1)+i+step);
                _lod[_currentLod]._indices.push_back(gridY*(gridX+1)+i);
                _lod[_currentLod]._indices.push_back(gridY*(gridX+1)+i+step);
            }
        }
        if(_back&&_back->_currentLod > _currentLod)//back
        {
            for(int i =0;i<gridX;i+=next_step)
            {
                _lod[_currentLod]._indices.push_back(i);
                _lod[_currentLod]._indices.push_back(step*(gridX+1) +i);
                _lod[_currentLod]._indices.push_back(step*(gridX+1) +i+step);

                _lod[_currentLod]._indices.push_back(i);
                _lod[_currentLod]._indices.push_back(step*(gridX+1) +i+step);
                _lod[_currentLod]._indices.push_back(i+next_step);

                _lod[_currentLod]._indices.push_back(i+next_step);
                _lod[_currentLod]._indices.push_back(step*(gridX+1) +i+step);
                _lod[_currentLod]._indices.push_back(step*(gridX+1) +i+next_step);
            }
        }else{
            for(int i =step;i<gridX-step;i+=step)
            {
                _lod[_currentLod]._indices.push_back(i);
                _lod[_currentLod]._indices.push_back(step*(gridX+1)+i);
                _lod[_currentLod]._indices.push_back(step*(gridX+1)+i+step);

                _lod[_currentLod]._indices.push_back(i);
                _lod[_currentLod]._indices.push_back(step*(gridX+1)+i+step);
                _lod[_currentLod]._indices.push_back(i+step);
            }
        }

        _chunkIndices = _terrain->insertIndicesLOD(currentNeighborLOD,_currentLod,&_lod[_currentLod]._indices[0],(int)_lod[_currentLod]._indices.size());
    }else{
        //No lod difference, use simple method
        _lod[_currentLod]._indices.clear();
        for(int i =0;i<gridY;i+=step)
        {
            for(int j = 0;j<gridX;j+=step)
            {

                int nLocIndex = i * (gridX+1) + j;
                _lod[_currentLod]._indices.push_back (nLocIndex);
                _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1));
                _lod[_currentLod]._indices.push_back (nLocIndex + step);

                _lod[_currentLod]._indices.push_back (nLocIndex + step);
                _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1));
                _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1) + step);
            }
        }
        _chunkIndices = _terrain->insertIndicesLOD(currentNeighborLOD,_currentLod,&_lod[_currentLod]._indices[0],(int)_lod[_currentLod]._indices.size());
    }
}

void Terrain::Chunk::calculateAABB()
{
    std::vector<Vec3>pos;
    for(size_t i = 0, size = _originalVertices.size(); i < size; ++i)
    {
        pos.push_back(_originalVertices[i]._position);
    }
    _aabb.updateMinMax(&pos[0],pos.size());
}

void Terrain::Chunk::calculateSlope()
{
    //find max slope
    auto lowest = _originalVertices[0]._position;
    for(size_t i = 0, size = _originalVertices.size(); i < size; ++i)
    {
        if(_originalVertices[i]._position.y< lowest.y)
        {
            lowest = _originalVertices[i]._position;
        }
    }
    auto highest = _originalVertices[0]._position;
    for(size_t i = 0, size = _originalVertices.size(); i < size; ++i)
    {
        if(_originalVertices[i]._position.y> highest.y)
        {
            highest = _originalVertices[i]._position;
        }
    }
    Vec2 a(lowest.x,lowest.z);
    Vec2 b(highest.x,highest.z);
    float dist = a.distance(b);
    _slope = (highest.y - lowest.y)/dist;
}

bool Terrain::Chunk::getIntersectPointWithRay(const Ray& ray, Vec3& intersectPoint)
{
    if (!ray.intersects(_aabb))
        return false;

    float minDist = FLT_MAX;
    bool isFind = false;
    for (auto triangle : _trianglesList)
    {
        Vec3 p;
        if (triangle.getIntersectPoint(ray, p))
        {
            float dist = ray._origin.distance(p);
            if (dist<minDist)
            {
            intersectPoint = p;
            minDist = dist;
            }
            isFind =true;
        }
    }

    return isFind;
}

bool Terrain::Chunk::getInsterctPointWithRay(const Ray& ray, Vec3& intersectPoint)
{
    return getIntersectPointWithRay(ray, intersectPoint);
}

void Terrain::Chunk::updateVerticesForLOD()
{
    if(_oldLod == _currentLod){ return;} // no need to update vertices
    _currentVertices = _originalVertices;
    int gridY = _size.height;
    int gridX = _size.width;

    if (_currentLod >= 2 && std::abs(_slope) > 1.2f)
    {
        int step = 1<<_currentLod;
        for(int i =step;i<gridY-step;i+=step)
            for(int j = step; j<gridX-step;j+=step)
            {
                // use linear-sample adjust vertices height
                float height = 0;
                float count = 0;
                for(int n = i-step/2;n<i+step/2;n++)
                {
                    for(int m = j-step/2;m<j+step/2;m++)
                    {
                        float weight = (step/2 - std::abs(n-i))*(step/2 - std::abs(m-j));
                        height += _originalVertices[m*(gridX+1)+n]._position.y;
                        count += weight;
                    }
                }
                _currentVertices[i*(gridX+1)+j]._position.y = height/count;
            }
    }

    glBufferData(GL_ARRAY_BUFFER, sizeof(TerrainVertexData)*_currentVertices.size(), &_currentVertices[0], GL_STREAM_DRAW);
    _oldLod = _currentLod;
}

Terrain::Chunk::~Chunk()
{
    glDeleteBuffers(1,&_vbo);
}

void Terrain::Chunk::updateIndicesLODSkirt()
{
    if(_oldLod == _currentLod) return;
    _oldLod = _currentLod;
    bool isOk;
    _chunkIndices =  _terrain->lookForIndicesLODSkrit(_currentLod,&isOk);
    if(isOk) return;

    int gridY = _size.height;
    int gridX = _size.width;
    int step = 1<<_currentLod;
    int k =0;
    for(int i =0;i<gridY;i+=step,k+=step)
    {
        for(int j = 0;j<gridX;j+=step)
        {
            int nLocIndex = i * (gridX+1) + j;
            _lod[_currentLod]._indices.push_back (nLocIndex);
            _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1));
            _lod[_currentLod]._indices.push_back (nLocIndex + step);

            _lod[_currentLod]._indices.push_back (nLocIndex + step);
            _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1));
            _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1) + step);
        }
    }
    //add skirt
    //#1
    for(int i =0;i<gridY;i+=step)
    {
        int nLocIndex = i * (gridX+1) + gridX;
        _lod[_currentLod]._indices.push_back (nLocIndex);
        _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1));
        _lod[_currentLod]._indices.push_back ((gridY+1) *(gridX+1)+i);

        _lod[_currentLod]._indices.push_back ((gridY+1) *(gridX+1)+i);
        _lod[_currentLod]._indices.push_back (nLocIndex + step * (gridX+1));
        _lod[_currentLod]._indices.push_back ((gridY+1) *(gridX+1)+i+step);
    }

    //#2
    for(int j =0;j<gridX;j+=step)
    {
        int nLocIndex = (gridY)* (gridX+1) + j;
        _lod[_currentLod]._indices.push_back (nLocIndex);
        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[1] +j);
        _lod[_currentLod]._indices.push_back (nLocIndex + step);

        _lod[_currentLod]._indices.push_back (nLocIndex + step);
        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[1] +j);
        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[1] +j + step);
    }

    //#3
    for(int i =0;i<gridY;i+=step)
    {
        int nLocIndex = i * (gridX+1);
        _lod[_currentLod]._indices.push_back (nLocIndex);
        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[2]+i);
        _lod[_currentLod]._indices.push_back ((i+step)*(gridX+1));

        _lod[_currentLod]._indices.push_back ((i+step)*(gridX+1));
        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[2]+i);
        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[2]+i +step);
    }

    //#4
    for(int j =0;j<gridX;j+=step)
    {
        int nLocIndex = j;
        _lod[_currentLod]._indices.push_back (nLocIndex + step);
        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[3]+j);
        _lod[_currentLod]._indices.push_back (nLocIndex);


        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[3] + j + step);
        _lod[_currentLod]._indices.push_back (_terrain->_skirtVerticesOffset[3] +j);
        _lod[_currentLod]._indices.push_back (nLocIndex + step);
    }

    _chunkIndices = _terrain->insertIndicesLODSkirt(_currentLod,&_lod[_currentLod]._indices[0], (int)_lod[_currentLod]._indices.size());
}

Terrain::QuadTree::QuadTree(int x, int y, int w, int h, Terrain * terrain)
{
    _terrain = terrain;
    _needDraw = true;
    _parent = nullptr;
    _tl =nullptr;
    _tr =nullptr;
    _bl =nullptr;
    _br =nullptr;
    _posX = x;
    _posY = y;
    this->_height = h;
    this->_width = w;
    if(_width> terrain->_chunkSize.width &&_height >terrain->_chunkSize.height) //subdivision
    {
        _isTerminal = false;
        this->_tl = new (std::nothrow) QuadTree(x,y,_width/2,_height/2,terrain);
        this->_tl->_parent = this;
        this->_tr = new (std::nothrow) QuadTree(x+_width/2,y,_width/2,_height/2,terrain);
        this->_tr->_parent = this;
        this->_bl = new (std::nothrow) QuadTree(x,y+_height/2,_width/2,_height/2,terrain);
        this->_bl->_parent = this;
        this->_br = new (std::nothrow) QuadTree(x+_width/2,y+_height/2,_width/2,_height/2,terrain);
        this->_br->_parent = this;

        _localAABB.merge(_tl->_localAABB);
        _localAABB.merge(_tr->_localAABB);
        _localAABB.merge(_bl->_localAABB);
        _localAABB.merge(_br->_localAABB);
    }else // is terminal Node
    {
        int m = _posY/terrain->_chunkSize.height;
        int n = _posX/terrain->_chunkSize.width;
        _chunk = terrain->_chunkesArray[m][n];
        _isTerminal = true;
        _localAABB = _chunk->_aabb;
        _chunk->_parent = this;

        for (auto & triangle : _chunk->_trianglesList)
        {
            triangle.transform(_terrain->getNodeToWorldTransform());
        }
    }
    _worldSpaceAABB = _localAABB;
    _worldSpaceAABB.transform(_terrain->getNodeToWorldTransform());
}

void Terrain::QuadTree::draw()
{
    if(!_needDraw)return;
    if(_isTerminal){
        this->_chunk->bindAndDraw();
    }else
    {
        this->_tl->draw();
        this->_tr->draw();
        this->_br->draw();
        this->_bl->draw();
    }
}

void Terrain::QuadTree::resetNeedDraw(bool value)
{
    this->_needDraw = value;
    if(!_isTerminal)
    {
        _tl->resetNeedDraw(value);
        _tr->resetNeedDraw(value);
        _bl->resetNeedDraw(value);
        _br->resetNeedDraw(value);
    }
}

void Terrain::QuadTree::cullByCamera(const Camera * camera, const Mat4 & worldTransform)
{
    if(!camera->isVisibleInFrustum(&_worldSpaceAABB))
    {
        this->resetNeedDraw(false);
    }else
    {
        if(!_isTerminal){
            _tl->cullByCamera(camera,worldTransform);
            _tr->cullByCamera(camera,worldTransform);
            _bl->cullByCamera(camera,worldTransform);
            _br->cullByCamera(camera,worldTransform);
        }
    }
}

void Terrain::QuadTree::preCalculateAABB(const Mat4 & worldTransform)
{

    _worldSpaceAABB = _localAABB;
    _worldSpaceAABB.transform(worldTransform);
    if(!_isTerminal){
        _tl->preCalculateAABB(worldTransform);
        _tr->preCalculateAABB(worldTransform);
        _bl->preCalculateAABB(worldTransform);
        _br->preCalculateAABB(worldTransform);
    }
}

Terrain::QuadTree::~QuadTree()
{
    if(_tl) delete _tl;
    if(_tr) delete _tr;
    if(_bl) delete _bl;
    if(_br) delete _br;
}

Terrain::TerrainData::TerrainData(const std::string& heightMapsrc , const std::string& textureSrc, const Size & chunksize, float height, float scale)
{
    this->_heightMapSrc = heightMapsrc;
    this->_detailMaps[0]._detailMapSrc = textureSrc;
    this->_alphaMapSrc = "";
    this->_chunkSize = chunksize;
    this->_mapHeight = height;
    this->_mapScale = scale;
    _skirtHeightRatio = 1;
}

Terrain::TerrainData::TerrainData(const std::string& heightMapsrc, const std::string& alphamap, const DetailMap& detail1, const DetailMap& detail2, const DetailMap& detail3, const DetailMap& detail4, const Size & chunksize, float height, float scale)
{
    this->_heightMapSrc = heightMapsrc;
    this->_alphaMapSrc = alphamap;
    this->_detailMaps[0] = detail1;
    this->_detailMaps[1] = detail2;
    this->_detailMaps[2] = detail3;
    this->_detailMaps[3] = detail4;
    this->_chunkSize = chunksize;
    this->_mapHeight = height;
    this->_mapScale = scale;
    _detailMapAmount = 4;
    _skirtHeightRatio = 1;
}

Terrain::TerrainData::TerrainData(const std::string& heightMapsrc, const std::string& alphamap, const DetailMap& detail1, const DetailMap& detail2, const DetailMap& detail3, const Size & chunksize /*= Size(32,32)*/, float height /*= 2*/, float scale /*= 0.1*/)
{
    this->_heightMapSrc = heightMapsrc;
    this->_alphaMapSrc = alphamap;
    this->_detailMaps[0] = detail1;
    this->_detailMaps[1] = detail2;
    this->_detailMaps[2] = detail3;
    this->_chunkSize = chunksize;
    this->_mapHeight = height;
    this->_mapScale = scale;
    _detailMapAmount = 3;
    _skirtHeightRatio = 1;
}

Terrain::TerrainData::TerrainData()
{

}

Terrain::DetailMap::DetailMap(const std::string& detailMapPath, float size /*= 35*/)
{
    this->_detailMapSrc = detailMapPath;
    this->_detailMapSize = size;
}

Terrain::DetailMap::DetailMap()
{
    _detailMapSrc = "";
    _detailMapSize = 35;
}

Terrain::Triangle::Triangle(const Vec3& p1, const Vec3& p2, const Vec3& p3)
{
    _p1 = p1;
    _p2 = p2;
    _p3 = p3;
}

void Terrain::Triangle::transform(const cocos2d::Mat4& matrix)
{
    matrix.transformPoint(&_p1);
    matrix.transformPoint(&_p2);
    matrix.transformPoint(&_p3);
}

//Please refer to 3D Math Primer for Graphics and Game Development
bool Terrain::Triangle::getIntersectPoint(const Ray& ray, Vec3& intersectPoint) const
{
    // E1
    Vec3 E1 = _p2 - _p1;

    // E2
    Vec3 E2 = _p3 - _p1;

    // P
    Vec3 P;
    Vec3::cross(ray._direction,E2,&P);

    // determinant
    float det =  E1.dot(P);

    // keep det > 0, modify T accordingly
    Vec3 T;
    if (det > 0)
    {
        T = ray._origin - _p1;
    }
    else
    {
        T = _p1 - ray._origin;
        det = -det;
    }

    // If determinant is near zero, ray lies in plane of triangle
    if (det < 0.0001f)
        return false;

     float t; // ray dist
     float u,v;//barycentric coordinate
    // Calculate u and make sure u <= 1
    u = T.dot(P);
    if (u < 0.0f || u > det)
        return false;

    // Q
    Vec3 Q;
    Vec3::cross(T,E1,&Q);

    // Calculate v and make sure u + v <= 1
    v = ray._direction.dot(Q);
    if (v < 0.0f || u + v > det)
        return false;

    // Calculate t, scale parameters, ray intersects triangle
    t = E2.dot(Q);

    float fInvDet = 1.0f / det;
    t *= fInvDet;

    intersectPoint = ray._origin + ray._direction * t;
    return true;
}

bool Terrain::Triangle::getInsterctPoint(const Ray& ray, Vec3& intersectPoint) const
{
    return getIntersectPoint(ray, intersectPoint);
}

NS_CC_END