cocos2dx v3.x box2d DrawDebugData 後置問題

.衆所周知, box2d的DrawDebugData函數繪制預設不是放在最前面的, 為了達到這個要求, v2版代碼很簡單

v2:

void Box2dManager::draw(){
    ccGLEnableVertexAttribs( kCCVertexAttribFlag_Position );
    kmGLPushMatrix();
    box2dWorld->DrawDebugData();
    kmGLPopMatrix();
}
           

v3:

v3版找了很久, 貌似研究的人不多, 不過找的過程中, 有人分析v3為了提高性能, 将v2那種單獨渲染變成了集中渲染, 在draw中并不馬上執行渲染, 這時候使用代碼:

void Box2dManager::draw(Renderer *renderer, const Mat4& transform, uint32_t flags){
    GL::enableVertexAttribs( GL::VERTEX_ATTRIB_FLAG_POSITION );
    Director::getInstance()->pushMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
    box2dWorld->DrawDebugData();
    Director::getInstance()->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
}
           

這個寫法是完全從v2過度過來的, 但很遺憾, 并沒有實作該有的功能

而根據v3方式把要渲染的順序加入到渲染序列中, 通過調用onDraw來進行上面的代碼, 這時候才能有效的讓渲染懸浮在其他sprite之上

void Box2dManager::draw(Renderer *renderer, const Mat4& transform, uint32_t flags){
    super::draw(renderer, transform, _transformUpdated);
    GL::enableVertexAttribs( cocos2d::GL::VERTEX_ATTRIB_FLAG_POSITION );
    Director* director = Director::getInstance();
    CCASSERT(nullptr != director, "Director is null when seting matrix stack");
    director->pushMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
    _modelViewMV = director->getMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
    _customCommand.init(_globalZOrder);
    _customCommand.func = CC_CALLBACK_0(Box2dManager::onDraw, this);
    renderer->addCommand(&_customCommand);
    director->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
}

void Box2dManager::onDraw() {
    Director* director = Director::getInstance();
    CCASSERT(nullptr != director, "Director is null when seting matrix stack");
    Mat4 oldMV;
    oldMV = director->getMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
    director->loadMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW, _modelViewMV);
    box2dWorld->DrawDebugData();
    director->loadMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW, oldMV);
}
           

參考:

Box2d debug drawing for cocos2d-x 3.0

B2DebugDrawLayer attachment

Cocos2d-x 3.2的渲染流程

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