通用编程能力训练：template

目的： 写一套操作摄像机的操作, 与具体引擎无关。

其中使用到了今天刚看的 template 相关重点。

non-const-getter macros, 为了少些代码

#ifndef _CONSTGETERHELPER_H_
#define _CONSTGETERHELPER_H_

#define NON_CONST_GETTER(ClassType, ReturnType, ConstGetter)\
	ReturnType ConstGetter(){ return const_cast<const ClassType*>(this)->ConstGetter();}

#define NON_CONST_GETTER1(ClassType, ReturnType, ConstGetter,ParamType1)\
	ReturnType ConstGetter(ParamType1 param1){ return const_cast<const ClassType*>(this)->ConstGetter(param1);}

#define NON_CONST_GETTER2(ClassType, ReturnType, ConstGetter, ParamType1, ParamType2)\
	ReturnType ConstGetter(ParamType1 param1, ParamType2 param2){ return const_cast<const ClassType*>(this)->ConstGetter(param1, param2);}

#define NON_CONST_GETTER3(ClassType, ReturnType, ConstGetter, ParamType1, ParamType2, ParamType3)\
	ReturnType ConstGetter(ParamType1 param1, ParamType2 param2, ParamType3 param3){ return const_cast<const ClassType*>(this)->ConstGetter(param1, param2, param3);}

#endif

抽象 Camera, 其中的 namespace 名称是女朋友提的:)

#pragma once

#include "ConstGeterHelper.h"

namespace Sakula
{
	template<typename _Camera, typename _Vector3, typename _Quaternion>
	class ICameraAdaptor
	{
	public:
		typedef _Camera CustomCameraType;
		typedef _Vector3 Vector3Type;
		typedef _Quaternion QuaternionType;
	public:
		virtual Vector3Type getPosition() const=0;
		virtual void setPosition(const Vector3Type& pos) = 0;
		virtual QuaternionType getOrientation() const=0;
		virtual void setOrientation(const QuaternionType& quat) = 0;
		virtual void destroyCamera() = 0;
	};

	template<typename CameraAdaptorImpl>
	class CameraAdaptorT : public CameraAdaptorImpl
	{
	public:
		typedef typename CameraAdaptorImpl::CustomCameraType CustomCameraType;
		typedef typename CameraAdaptorImpl::Vector3Type Vector3Type;
		typedef typename CameraAdaptorImpl::QuaternionType QuaternionType;
		
	public:
		CameraAdaptorT(CustomCameraType* c)
			:camera(c)
		{
		};

		~CameraAdaptorT()
		{
		};

	public:
		using typename CameraAdaptorImpl::getPosition;
		NON_CONST_GETTER( CameraAdaptorT, Vector3Type, getPosition);
		Vector3Type getPosition() const
		{
			return this->getPosition();
		}

		void setPosition(const Vector3Type& v)
		{
			this->setPosition(v);
		}

		using typename CameraAdaptorImpl::setOrientation;
		NON_CONST_GETTER( CameraAdaptorT, QuaternionType, getOrientation);
		QuaternionType getOrientation() const
		{
			return this->getOrientation();
		}

		void setOrientation(const QuaternionType& v)
		{
			this->setOrientation(v);
		}

		using typename CameraAdaptorImpl::destroyCamera;
		void destroyCamera()
		{
			this->destroyCamera();
		}

	protected:
		CustomCameraType* camera;
	};
}

基于 OgreCamera 的实现版本

OgreCameraAdaptor.h

#pragma once

namespace Ogre
{
	class Camera;
	class Quaternion;
	class Vector3;
};

#include "AdaptorT\CameraAdaptorT.h"

namespace Sakula
{
	typedef Sakula::CameraAdaptorT< Sakula::ICameraAdaptor<Ogre::Camera, Ogre::Vector3, Ogre::Quaternion> > OgreCameraAdaptorBase;
	class OgreCameraAdaptor : public OgreCameraAdaptorBase
	{
	public:
		OgreCameraAdaptor(Ogre::Camera* c);
		~OgreCameraAdaptor();

	public:
		virtual Vector3Type getPosition()const;
		virtual void setPosition( const Vector3Type& pos);

		virtual QuaternionType getOrientation()const;
		virtual void setOrientation(const QuaternionType& quat);

		virtual void destroyCamera();
	};
}

OgreCameraAdaptor.cpp

#include "stdafx.h"
#include "OgreCameraAdaptor.h"

#include "OgreVector3.h"
#include "OgreQuaternion.h"
#include "OgreCamera.h"
#include "OgreSceneManager.h"

Sakula::OgreCameraAdaptor::OgreCameraAdaptor(Ogre::Camera* c)
:OgreCameraAdaptorBase(c)
{
}

Sakula::OgreCameraAdaptor::~OgreCameraAdaptor()
{
}

Sakula::OgreCameraAdaptor::Vector3Type Sakula::OgreCameraAdaptor::getPosition()const
{
	return camera->getPosition();
}

void Sakula::OgreCameraAdaptor::setPosition( const Vector3Type& pos)
{
	camera->setPosition(pos);
}

Sakula::OgreCameraAdaptor::QuaternionType Sakula::OgreCameraAdaptor::getOrientation()const
{
	return camera->getOrientation();
}

void Sakula::OgreCameraAdaptor::setOrientation(const QuaternionType& quat)
{
	camera->setOrientation(quat);
}

void Sakula::OgreCameraAdaptor::destroyCamera()
{
	Ogre::SceneManager* sm = camera->getSceneManager();
	sm->destroyCamera(camera);
	camera = NULL;
}

当然，这里没有对 Vector3 和 Quaternion 做适配接口， 实际上我是写了的， 因为各家的 Vector3 和 Quaternion 都不尽相同。计算函数也不一样，所以需要更多的提炼，慢慢写吧，希望年前能写一套比较完善的摄像机操作。