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Cocos2d-x transition class adapter that allows one to pop scene with a transition non-intrusively
#include <type_traits>
#include <cocos2d.h>
#pragma once
//------------------------------------------------------------------------------
/// Transition adapter that pops current scene with transition passed as an argument.
///
/// Example:
/// Instead of calling cocos2d::Director::getInstance()->popScene() just call:
///
/// cocos2d::Director::getInstance()->pushScene(
/// pop_scene_with<cocos2d::TransitionFlipX>::create(1.0f, cocos2d::TransitionScene::Orientation::LEFT_OVER)
/// );
///
/// Note that there is no typical 2nd argument taking the scene for the transition,
/// one simply passes all the arguments they would pass to the transition's create
/// method except for the 2nd argument carrying the scene.
template <typename Transition>
struct pop_scene_with : Transition
{
static_assert(std::is_base_of<cocos2d::TransitionScene, Transition>::value, "Type argument must be a class derived from cocos2d::TransitionScene");
private:
/// A helper class to access protected member of a director we need
struct DirectorAccessor : cocos2d::Director
{
/// Returns the scene that is previous to the current scene.
cocos2d::Scene* getPreviousScene() const
{
assert(_scenesStack.size() > 1); // Top is current scene and the user is asking for previous, which must exist
return _scenesStack.at(_scenesStack.size() - 2);
}
};
/// Catch the end of the transition to pop the actual scene
virtual void onExit() override
{
Transition::onExit();
cocos2d::Director::getInstance()->popScene(); // Pop the replica of the previous scene we pushed
cocos2d::Director::getInstance()->popScene(); // Pop the scene we were actually trying to pop
}
public:
/// Creator of the scene popper.
template<typename... Args>
static pop_scene_with* create(float t, Args&&... args)
{
pop_scene_with* pThisScene = new (std::nothrow) pop_scene_with();
cocos2d::Scene* pPrevScene = static_cast<DirectorAccessor*>(cocos2d::Director::getInstance())->getPreviousScene();
if (pThisScene && pThisScene->initWithDuration(t, pPrevScene, std::forward<Args>(args)...))
{
pThisScene->autorelease();
return pThisScene;
}
CC_SAFE_DELETE(pThisScene);
return nullptr;
}
};
//------------------------------------------------------------------------------
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