在
// Draw the Scene
void Director::drawScene()
{
// calculate “global” dt
calculateDeltaTime();
// skip one flame when _deltaTime equal to zero.
if(_deltaTime < FLT_EPSILON)
{
return;
}
if (_openGLView)
{
_openGLView->pollEvents();
}
//tick before glClear: issue #533
if (! _paused)
{
_scheduler->update(_deltaTime);
_eventDispatcher->dispatchEvent(_eventAfterUpdate);
}
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/* to avoid flickr, nextScene MUST be here: after tick and before draw.
* FIXME: Which bug is this one. It seems that it can't be reproduced with v0.9
*/
if (_nextScene)
{
setNextScene();
}
pushMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
if (_runningScene)
{
//clear draw stats
_renderer->clearDrawStats();
//render the scene
_runningScene->render(_renderer);
_eventDispatcher->dispatchEvent(_eventAfterVisit);
}
// draw the notifications node
if (_notificationNode)
{
_notificationNode->visit(_renderer, Mat4::IDENTITY, 0);
}
if (_displayStats)
{
showStats();
}
_renderer->render();
_eventDispatcher->dispatchEvent(_eventAfterDraw);
popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
_totalFrames++;
// swap buffers
if (_openGLView)
{
_openGLView->swapBuffers();
}
if (_displayStats)
{
calculateMPF();
}
}
上面的红色部分对游戏场景进行了一次渲染
但是绿色部分的代码如下：
void Scene::render(Renderer* renderer)
{
auto director = Director::getInstance();
Camera* defaultCamera = nullptr;
for (const auto& camera : _cameras)
{
Camera::_visitingCamera = camera;
if (Camera::_visitingCamera->getCameraFlag() == CameraFlag::DEFAULT)
{
defaultCamera = Camera::_visitingCamera;
continue;
}
director->pushMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);
director->loadMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION, Camera::_visitingCamera->getViewProjectionMatrix());
//visit the scene
visit(renderer, Mat4::IDENTITY, 0);
renderer->render();
director->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);
}
//draw with default camera
if (defaultCamera)
{
Camera::_visitingCamera = defaultCamera;
director->pushMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);
director->loadMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION, Camera::_visitingCamera->getViewProjectionMatrix());
//visit the scene
visit(renderer, Mat4::IDENTITY, 0);
renderer->render();
director->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);
}
Camera::_visitingCamera = nullptr;
}
也进行了一次渲染
自己测试将最上面的_renderer->render();部分注释掉，也可以正常渲染
什么要这样设计，是否有重复渲染？之前的3.0版本没有这个问题。