[COCOS2DX-LUA]0-004.cocos2dx中的DrawNode的init的方法问题

1.诱因

　　近期，项目接入了Bugly, 上报了一些平常测试不出来，或者很难重现的bug，这类bug非常难排查。原因有二，第一，问题无法重现，第二，修改了无法立即验证结果。有一个问题困恼了我很久，就是一直报这块的代码出错。(dispatchEvent报错)

void Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeInit(JNIEnv*  env, jobject thiz, jint w, jint h)
{
    auto director = cocos2d::Director::getInstance();
    auto glview = director->getOpenGLView();
    if (!glview)
    {
        glview = cocos2d::GLViewImpl::create("Android app");
        glview->setFrameSize(w, h);
        director->setOpenGLView(glview);

        //cocos_android_app_init(env, thiz);

        cocos2d::Application::getInstance()->run();
    }
    else
    {
        cocos2d::GL::invalidateStateCache();
        cocos2d::GLProgramCache::getInstance()->reloadDefaultGLPrograms();
        cocos2d::DrawPrimitives::init();
        cocos2d::VolatileTextureMgr::reloadAllTextures();

        cocos2d::EventCustom recreatedEvent(EVENT_RENDERER_RECREATED);
        director->getEventDispatcher()->dispatchEvent(&recreatedEvent);
        director->setGLDefaultValues();
    }
}

2.分析问题

这个一看就是为了防止安卓后台返回资源重建，就去查找所有有做资源重建的类，这一看就找到了以下代码。

bool DrawNode::init()
{
    _blendFunc = BlendFunc::ALPHA_PREMULTIPLIED;

    setGLProgramState(GLProgramState::getOrCreateWithGLProgramName(GLProgram::SHADER_NAME_POSITION_LENGTH_TEXTURE_COLOR));
    
    ensureCapacity(512);
    ensureCapacityGLPoint(64);
    ensureCapacityGLLine(256);
    
    if (Configuration::getInstance()->supportsShareableVAO())
    {
        glGenVertexArrays(1, &_vao);
        GL::bindVAO(_vao);
    }
    glGenBuffers(1, &_vbo);
    glBindBuffer(GL_ARRAY_BUFFER, _vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(V2F_C4B_T2F)* _bufferCapacity, _buffer, GL_STREAM_DRAW);
    // vertex
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_POSITION);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, vertices));
    // color
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_COLOR);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, colors));
    // texcood
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_TEX_COORD);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_TEX_COORD, 2, GL_FLOAT, GL_FALSE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, texCoords));
    
    if (Configuration::getInstance()->supportsShareableVAO())
    {
        glGenVertexArrays(1, &_vaoGLLine);
        GL::bindVAO(_vaoGLLine);
    }
    glGenBuffers(1, &_vboGLLine);
    glBindBuffer(GL_ARRAY_BUFFER, _vboGLLine);
    glBufferData(GL_ARRAY_BUFFER, sizeof(V2F_C4B_T2F)*_bufferCapacityGLLine, _bufferGLLine, GL_STREAM_DRAW);
    // vertex
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_POSITION);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, vertices));
    // color
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_COLOR);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, colors));
    // texcood
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_TEX_COORD);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_TEX_COORD, 2, GL_FLOAT, GL_FALSE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, texCoords));
    
    if (Configuration::getInstance()->supportsShareableVAO())
    {
        glGenVertexArrays(1, &_vaoGLPoint);
        GL::bindVAO(_vaoGLPoint);
    }
    glGenBuffers(1, &_vboGLPoint);
    glBindBuffer(GL_ARRAY_BUFFER, _vboGLPoint);
    glBufferData(GL_ARRAY_BUFFER, sizeof(V2F_C4B_T2F)*_bufferCapacityGLPoint, _bufferGLPoint, GL_STREAM_DRAW);
    // vertex
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_POSITION);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, vertices));
    // color
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_COLOR);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, colors));
    // texcood
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_TEX_COORD);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_TEX_COORD, 2, GL_FLOAT, GL_FALSE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, texCoords));

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    if (Configuration::getInstance()->supportsShareableVAO())
    {
        GL::bindVAO(0);
    }
    
    CHECK_GL_ERROR_DEBUG();
    
    _dirty = true;
    _dirtyGLLine = true;
    _dirtyGLPoint = true;
    
#if CC_ENABLE_CACHE_TEXTURE_DATA
        // Need to listen the event only when not use batchnode, because it will use VBO
        auto listener = EventListenerCustom::create(EVENT_RENDERER_RECREATED, [this](EventCustom* event){
       /** listen the event that renderer was recreated on Android */
            this->init();//此处会一直添加监听，重复添加
        });

        _eventDispatcher->addEventListenerWithSceneGraphPriority(listener, this);
#endif
    
    return true;
}