前言

在3D游戏当中，我们经常会使用到照相机这个东西，无论你使用的是哪一款引擎，都会用到，同时，照相机这个东西涉及到的东西比较多，基础知识需要扎实一些才可以。

如何使用

很久之前做项目的时候用到过一次，已经忘记的差不多了。为此，我找了cpp test中的示例代码，找了一个相对简单的代码，我把关键代码贴出来。

auto layer3D=Layer::create();
addChild(layer3D,0);
_layer3D=layer3D;_shader =GLProgram::createWithFilenames("Sprite3DTest/fog.vert","Sprite3DTest/fog.frag");
_state = GLProgramState::create(_shader);_sprite3D1 = Sprite3D::create("Sprite3DTest/teapot.c3b");
_sprite3D2 = Sprite3D::create("Sprite3DTest/teapot.c3b");_sprite3D1->setGLProgramState(_state);
_sprite3D2->setGLProgramState(_state);
//pass mesh's attribute to shader
long offset = 0;
auto attributeCount = _sprite3D1->getMesh()->getMeshVertexAttribCount();
for (auto i = 0; i < attributeCount; i++) {auto meshattribute = _sprite3D1->getMesh()->getMeshVertexAttribute(i);_state->setVertexAttribPointer(s_attributeNames[meshattribute.vertexAttrib],meshattribute.size, meshattribute.type,GL_FALSE,_sprite3D1->getMesh()->getVertexSizeInBytes(),(GLvoid*)offset);offset += meshattribute.attribSizeBytes;
}long offset1 = 0;
auto attributeCount1 = _sprite3D2->getMesh()->getMeshVertexAttribCount();
for (auto i = 0; i < attributeCount1; i++) {auto meshattribute = _sprite3D2->getMesh()->getMeshVertexAttribute(i);_state->setVertexAttribPointer(s_attributeNames[meshattribute.vertexAttrib],meshattribute.size, meshattribute.type,GL_FALSE,_sprite3D2->getMesh()->getVertexSizeInBytes(),(GLvoid*)offset1);offset1 += meshattribute.attribSizeBytes;
}_state->setUniformVec4("u_fogColor", Vec4(0.5,0.5,0.5,1.0));
_state->setUniformFloat("u_fogStart",10);
_state->setUniformFloat("u_fogEnd",60);
_state->setUniformInt("u_fogEquation" ,0);_layer3D->addChild(_sprite3D1);
_sprite3D1->setPosition3D( Vec3( 0, 0,0 ) );
_sprite3D1->setScale(2.0f);
_sprite3D1->setRotation3D(Vec3(-90,180,0));_layer3D->addChild(_sprite3D2);
_sprite3D2->setPosition3D( Vec3( 0, 0,-20 ) );
_sprite3D2->setScale(2.0f);
_sprite3D2->setRotation3D(Vec3(-90,180,0));// 在所有子节点都创建完了以后才创建照相机
if (_camera == nullptr)
{// 创建投影的摄像机_camera=Camera::createPerspective(60, (GLfloat)s.width/s.height, 1, 1000);// 设置标识符_camera->setCameraFlag(CameraFlag::USER1);_camera->setPosition3D(Vec3(0, 30, 40));// 设置摄像机看着目标_camera->lookAt(Vec3(0,0,0), Vec3(0, 1, 0));// 记得把摄像机加入到场景中_layer3D->addChild(_camera);
}
_layer3D->setCameraMask(2);

这段代码其实就是创建了一个3d的模型，并且让照相机照着这个3d模型，可以重点看创建照相机的代码。

源码分析

源码中的英文注释已经说的很详细了，但我还是用英文来写一下。

.h文件代码：

 ****************************************************************************/
#ifndef _CCCAMERA_H__
#define _CCCAMERA_H__#include "2d/CCNode.h"
#include "3d/CCFrustum.h"
#include "renderer/CCQuadCommand.h"
#include "renderer/CCCustomCommand.h"
#include "renderer/CCFrameBuffer.h"NS_CC_BEGINclass Scene;
class CameraBackgroundBrush;/*** Note: * Scene creates a default camera. And the default camera mask of Node is 1, therefore it can be seen by the default camera.* During rendering the scene, it draws the objects seen by each camera in the added order except default camera. The default camera is the last one being drawn with.* It's usually a good idea to render 3D objects in a separate camera.* And set the 3d camera flag to CameraFlag::USER1 or anything else except DEFAULT. Dedicate The DEFAULT camera for UI, because it is rendered at last.* You can change the camera order to get different result when depth test is not enabled.* For each camera, transparent 3d sprite is rendered after opaque 3d sprite and other 2d objects.*/
// 上面英文就已经介绍的很好了，
// 相机的标识符，每个Node中有个_cameraMask的属性，当相机的_cameraFlag & _cameraMask为true时，
// 该Node可以被相机看到
enum class CameraFlag
{DEFAULT = 1,USER1 = 1 << 1,USER2 = 1 << 2,USER3 = 1 << 3,USER4 = 1 << 4,USER5 = 1 << 5,USER6 = 1 << 6,USER7 = 1 << 7,USER8 = 1 << 8,
};
/*** Defines a camera .*/
class CC_DLL Camera :public Node
{friend class Scene;friend class Director;friend class EventDispatcher;
public:/*** The type of camera.*/// 相机类型，分别是投影和正交enum class Type{PERSPECTIVE = 1,ORTHOGRAPHIC = 2};
public:/*** Creates a perspective camera.** @param fieldOfView The field of view for the perspective camera (normally in the range of 40-60 degrees).* @param aspectRatio The aspect ratio of the camera (normally the width of the viewport divided by the height of the viewport).* @param nearPlane The near plane distance.* @param farPlane The far plane distance.*//**创建一个透视相机。参数：fieldOfView 透视相机的可视角度 (一般是在40-60度之间).aspectRatio 相机的长宽比(通常会使用视窗的宽度除以视窗的高度)。nearPlane   近平面的距离。farPlane    远平面的距离。*/static Camera* createPerspective(float fieldOfView, float aspectRatio, float nearPlane, float farPlane);/*** Creates an orthographic camera.** @param zoomX The zoom factor along the X-axis of the orthographic projection (the width of the ortho projection).* @param zoomY The zoom factor along the Y-axis of the orthographic projection (the height of the ortho projection).* @param nearPlane The near plane distance.* @param farPlane The far plane distance.*//**创建一个正交相机。参数:zoomX   沿x轴的正交投影的缩放因子(正交投影的宽度)。zoomY   沿y轴的正交投影的缩放因子(正交投影的高度)。nearPlane   近平面的距离。farPlane    远平面的距离。*/static Camera* createOrthographic(float zoomX, float zoomY, float nearPlane, float farPlane);/** create default camera, the camera type depends on Director::getProjection, the depth of the default camera is 0 *//**创建默认的相机,相机的类型取决于Director::getProjection,默认的相机深度是0*/static Camera* create();/*** Gets the type of camera.** @return The camera type.*/Camera::Type getType() const { return _type; }/**get & set Camera flag*/CameraFlag getCameraFlag() const { return (CameraFlag)_cameraFlag; }void setCameraFlag(CameraFlag flag) { _cameraFlag = (unsigned short)flag; }/*** Make Camera looks at target** @param target The target camera is point at* @param up The up vector, usually it's Y axis*//**使相机看着目标参数：target  目标的位置up  相机向上的向量,通常这是Y轴*/virtual void lookAt(const Vec3& target, const Vec3& up = Vec3::UNIT_Y);/*** Gets the camera's projection matrix.** @return The camera projection matrix.*//**获取相机的投影矩阵。返回：相机投影矩阵。*/const Mat4& getProjectionMatrix() const;/*** Gets the camera's view matrix.** @return The camera view matrix.*//**获取相机的视图矩阵。返回：相机视图矩阵。*/const Mat4& getViewMatrix() const;/**get view projection matrix*//**得到视图投影矩阵。*/const Mat4& getViewProjectionMatrix() const;/* convert the specified point in 3D world-space coordinates into the screen-space coordinates.** Origin point at left top corner in screen-space.* @param src The world-space position.* @return The screen-space position.*//*把指定坐标点从世界坐标转换为屏幕坐标。 原点在屏幕坐标系的左上角。参数：src 世界的位置。返回：屏幕的位置。*/Vec2 project(const Vec3& src) const;/* convert the specified point in 3D world-space coordinates into the GL-screen-space coordinates.** Origin point at left bottom corner in GL-screen-space.* @param src The 3D world-space position.* @return The GL-screen-space position.*//*把指定坐标点从3D世界坐标转换为GL坐标。 原点在GL屏幕坐标系的左下角。参数：src 3D世界的位置。返回：GL屏幕空间的位置。*/Vec2 projectGL(const Vec3& src) const;/*** Convert the specified point of screen-space coordinate into the 3D world-space coordinate.** Origin point at left top corner in screen-space.* @param src The screen-space position.* @return The 3D world-space position.*/// 和上面的相反Vec3 unproject(const Vec3& src) const;/*** Convert the specified point of GL-screen-space coordinate into the 3D world-space coordinate.** Origin point at left bottom corner in GL-screen-space.* @param src The GL-screen-space position.* @return The 3D world-space position.*/// 和上面的相反Vec3 unprojectGL(const Vec3& src) const;/*** Convert the specified point of screen-space coordinate into the 3D world-space coordinate.** Origin point at left top corner in screen-space.* @param size The window size to use.* @param src  The screen-space position.* @param dst  The 3D world-space position.*/void unproject(const Size& size, const Vec3* src, Vec3* dst) const;/*** Convert the specified point of GL-screen-space coordinate into the 3D world-space coordinate.** Origin point at left bottom corner in GL-screen-space.* @param size The window size to use.* @param src  The GL-screen-space position.* @param dst  The 3D world-space position.*/void unprojectGL(const Size& size, const Vec3* src, Vec3* dst) const;/*** Is this aabb visible in frustum*//**aabb在视椎体内是否可见*/bool isVisibleInFrustum(const AABB* aabb) const;/*** Get object depth towards camera*//**获取朝向相机的物体深度。*/float getDepthInView(const Mat4& transform) const;/*** set depth, camera with larger depth is drawn on top of camera with smaller depth, the depth of camera with CameraFlag::DEFAULT is 0, user defined camera is -1 by default*//**设置深度，相比深度小的，深度较大的相机会绘制在顶端，标识是CameraFlag::DEFAULT的相机深度是0，用户定义的相机深度默认为-1*/void setDepth(int8_t depth);/*** get depth, camera with larger depth is drawn on top of camera with smaller depth, the depth of camera with CameraFlag::DEFAULT is 0, user defined camera is -1 by default*/int8_t getDepth() const { return _depth; }/**get rendered order*//**获取渲染顺序。*/int getRenderOrder() const;/*** Get the frustum's far plane.*//**获取视椎体远平面。*/float getFarPlane() const { return _farPlane; }/*** Get the frustum's near plane.*//**获取视椎体近平面。*/float getNearPlane() const { return _nearPlane; }//overridevirtual void onEnter() override;virtual void onExit() override;/*** Get the visiting camera , the visiting camera shall be set on Scene::render*//**获取绘制的相机,绘制的相机会在Scene::render中设置。*/static const Camera* getVisitingCamera() { return _visitingCamera; }/*** Get the default camera of the current running scene.*//**获取到当前运行场景的默认相机。*/static Camera* getDefaultCamera();/**Before rendering scene with this camera, the background need to be cleared. It clears the depth buffer with max depth by default. Use setBackgroundBrush to modify the default behavior*//**在相机渲染所属的场景前，需要对背景进行清除。它以默认的深度值清除缓存，可以通过setBackgroundBrush 函数获取深度值。*/void clearBackground();/**Apply the FBO, RenderTargets and viewport.*//**应用帧缓冲，渲染目标和视图。*/void apply();/**Set FBO, which will attach several render target for the rendered result.*//**设置帧缓冲，从中可以获取到一些需要渲染的目标。*/void setFrameBufferObject(experimental::FrameBuffer* fbo);/**Set Viewport for camera.*//**设置相机视口。*/void setViewport(const experimental::Viewport& vp) { _viewport = vp; }/*** Whether or not the viewprojection matrix was updated since the last frame.* @return True if the viewprojection matrix was updated since the last frame.*//**视图矩阵是否在上一帧被更新。*/bool isViewProjectionUpdated() const {return _viewProjectionUpdated;}/*** set the background brush. See CameraBackgroundBrush for more information.* @param clearBrush Brush used to clear the background*//**设置背景刷，通过CameraBackgroundBrush 查看更多详情。*/void setBackgroundBrush(CameraBackgroundBrush* clearBrush);/*** Get clear brush*/CameraBackgroundBrush* getBackgroundBrush() const { return _clearBrush; }/**遍历所有子节点，并且循环递归得发送它们的渲染指令。参数:renderer    指定一个渲染器parentTransform 父节点放射变换矩阵parentFlags 渲染器标签重载 Node .*/virtual void visit(Renderer* renderer, const Mat4 &parentTransform, uint32_t parentFlags) override;bool isBrushValid();CC_CONSTRUCTOR_ACCESS:Camera();~Camera();/*** Set the scene,this method shall not be invoke manually*//**设置场景,这个方法不应该手动调用 .*/void setScene(Scene* scene);/**set additional matrix for the projection matrix, it multiplies mat to projection matrix when called, used by WP8*/void setAdditionalProjection(const Mat4& mat);/** init camera *//**初始化相机。包括透视相机和正交相机。*/bool initDefault();bool initPerspective(float fieldOfView, float aspectRatio, float nearPlane, float farPlane);bool initOrthographic(float zoomX, float zoomY, float nearPlane, float farPlane);void applyFrameBufferObject();void applyViewport();
protected:Scene* _scene; //Scene camera belongs toMat4 _projection;mutable Mat4 _view;mutable Mat4 _viewInv;mutable Mat4 _viewProjection;Vec3 _up;Camera::Type _type;float _fieldOfView;float _zoom[2];float _aspectRatio;float _nearPlane;float _farPlane;mutable bool  _viewProjectionDirty;bool _viewProjectionUpdated; //Whether or not the viewprojection matrix was updated since the last frame.unsigned short _cameraFlag; // camera flagmutable Frustum _frustum;   // camera frustummutable bool _frustumDirty;int8_t  _depth;                 //camera depth, the depth of camera with CameraFlag::DEFAULT flag is 0 by default, a camera with larger depth is drawn on top of camera with smaller depthstatic Camera* _visitingCamera;CameraBackgroundBrush* _clearBrush; //brush used to clear the back groundexperimental::Viewport _viewport;experimental::FrameBuffer* _fbo;
protected:static experimental::Viewport _defaultViewport;
public:static const experimental::Viewport& getDefaultViewport() { return _defaultViewport; }static void setDefaultViewport(const experimental::Viewport& vp) { _defaultViewport = vp; }
};

.cpp文件代码

 ****************************************************************************/
#include "2d/CCCamera.h"
#include "2d/CCCameraBackgroundBrush.h"
#include "base/CCDirector.h"
#include "platform/CCGLView.h"
#include "2d/CCScene.h"
#include "renderer/CCRenderer.h"
#include "renderer/CCQuadCommand.h"
#include "renderer/CCGLProgramCache.h"
#include "renderer/ccGLStateCache.h"
#include "renderer/CCFrameBuffer.h"
#include "renderer/CCRenderState.h"NS_CC_BEGINCamera* Camera::_visitingCamera = nullptr;
experimental::Viewport Camera::_defaultViewport;Camera* Camera::getDefaultCamera()
{auto scene = Director::getInstance()->getRunningScene();if(scene){return scene->getDefaultCamera();}return nullptr;
}Camera* Camera::create()
{Camera* camera = new (std::nothrow) Camera();camera->initDefault();camera->autorelease();camera->setDepth(0.f);return camera;
}Camera* Camera::createPerspective(float fieldOfView, float aspectRatio, float nearPlane, float farPlane)
{auto ret = new (std::nothrow) Camera();if (ret){ret->initPerspective(fieldOfView, aspectRatio, nearPlane, farPlane);ret->autorelease();return ret;}CC_SAFE_DELETE(ret);return nullptr;
}Camera* Camera::createOrthographic(float zoomX, float zoomY, float nearPlane, float farPlane)
{auto ret = new (std::nothrow) Camera();if (ret){ret->initOrthographic(zoomX, zoomY, nearPlane, farPlane);ret->autorelease();return ret;}CC_SAFE_DELETE(ret);return nullptr;
}Camera::Camera()
: _scene(nullptr)
, _viewProjectionDirty(true)
, _cameraFlag(1)
, _frustumDirty(true)
, _depth(-1)
, _fbo(nullptr)
{_frustum.setClipZ(true);_clearBrush = CameraBackgroundBrush::createDepthBrush(1.f);_clearBrush->retain();
}Camera::~Camera()
{CC_SAFE_RELEASE_NULL(_fbo);CC_SAFE_RELEASE(_clearBrush);
}const Mat4& Camera::getProjectionMatrix() const
{return _projection;
}
const Mat4& Camera::getViewMatrix() const
{Mat4 viewInv(getNodeToWorldTransform());static int count = sizeof(float) * 16;if (memcmp(viewInv.m, _viewInv.m, count) != 0){_viewProjectionDirty = true;_frustumDirty = true;_viewInv = viewInv;_view = viewInv.getInversed();}return _view;
}
void Camera::lookAt(const Vec3& lookAtPos, const Vec3& up)
{//camera->lookAt必须在camera->setPostion3D之后，因为其在运行过程中调用了getPosition3D()//定义y方向的归一化向量。Vec3 upv = up;upv.normalize();//计算x、y、z、方向上的向量。Vec3 zaxis;Vec3::subtract(this->getPosition3D(), lookAtPos, &zaxis);zaxis.normalize();Vec3 xaxis;Vec3::cross(upv, zaxis, &xaxis);xaxis.normalize();Vec3 yaxis;Vec3::cross(zaxis, xaxis, &yaxis);yaxis.normalize();//将上面计算的向量值构造旋转矩阵Mat4  rotation;rotation.m[0] = xaxis.x;rotation.m[1] = xaxis.y;rotation.m[2] = xaxis.z;rotation.m[3] = 0;rotation.m[4] = yaxis.x;rotation.m[5] = yaxis.y;rotation.m[6] = yaxis.z;rotation.m[7] = 0;rotation.m[8] = zaxis.x;rotation.m[9] = zaxis.y;rotation.m[10] = zaxis.z;rotation.m[11] = 0;/*定义四元数，将旋转矩阵转换为四元数。通过四元数来设置3D空间中的旋转角度。要保证四元数是经过归一化的。*/Quaternion  quaternion;Quaternion::createFromRotationMatrix(rotation,&quaternion);quaternion.normalize();setRotationQuat(quaternion);
}const Mat4& Camera::getViewProjectionMatrix() const
{getViewMatrix();if (_viewProjectionDirty){_viewProjectionDirty = false;Mat4::multiply(_projection, _view, &_viewProjection);}return _viewProjection;
}void Camera::setAdditionalProjection(const Mat4& mat)
{_projection = mat * _projection;getViewProjectionMatrix();
}bool Camera::initDefault()
{auto size = Director::getInstance()->getWinSize();//create default cameraauto projection = Director::getInstance()->getProjection();switch (projection){case Director::Projection::_2D:{initOrthographic(size.width, size.height, -1024, 1024);setPosition3D(Vec3(0.0f, 0.0f, 0.0f));setRotation3D(Vec3(0.f, 0.f, 0.f));break;}case Director::Projection::_3D:{float zeye = Director::getInstance()->getZEye();initPerspective(60, (GLfloat)size.width / size.height, 10, zeye + size.height / 2.0f);Vec3 eye(size.width/2, size.height/2.0f, zeye), center(size.width/2, size.height/2, 0.0f), up(0.0f, 1.0f, 0.0f);setPosition3D(eye);lookAt(center, up);break;}default:CCLOG("unrecognized projection");break;}return true;
}bool Camera::initPerspective(float fieldOfView, float aspectRatio, float nearPlane, float farPlane)
{_fieldOfView = fieldOfView;_aspectRatio = aspectRatio;_nearPlane = nearPlane;_farPlane = farPlane;Mat4::createPerspective(_fieldOfView, _aspectRatio, _nearPlane, _farPlane, &_projection);_viewProjectionDirty = true;_frustumDirty = true;return true;
}bool Camera::initOrthographic(float zoomX, float zoomY, float nearPlane, float farPlane)
{_zoom[0] = zoomX;_zoom[1] = zoomY;_nearPlane = nearPlane;_farPlane = farPlane;Mat4::createOrthographicOffCenter(0, _zoom[0], 0, _zoom[1], _nearPlane, _farPlane, &_projection);_viewProjectionDirty = true;_frustumDirty = true;return true;
}Vec2 Camera::project(const Vec3& src) const
{Vec2 screenPos;auto viewport = Director::getInstance()->getWinSize();Vec4 clipPos;getViewProjectionMatrix().transformVector(Vec4(src.x, src.y, src.z, 1.0f), &clipPos);CCASSERT(clipPos.w != 0.0f, "clipPos.w can't be 0.0f!");float ndcX = clipPos.x / clipPos.w;float ndcY = clipPos.y / clipPos.w;screenPos.x = (ndcX + 1.0f) * 0.5f * viewport.width;screenPos.y = (1.0f - (ndcY + 1.0f) * 0.5f) * viewport.height;return screenPos;
}Vec2 Camera::projectGL(const Vec3& src) const
{Vec2 screenPos;auto viewport = Director::getInstance()->getWinSize();Vec4 clipPos;getViewProjectionMatrix().transformVector(Vec4(src.x, src.y, src.z, 1.0f), &clipPos);CCASSERT(clipPos.w != 0.0f, "clipPos.w can't be 0.0f!");float ndcX = clipPos.x / clipPos.w;float ndcY = clipPos.y / clipPos.w;screenPos.x = (ndcX + 1.0f) * 0.5f * viewport.width;screenPos.y = (ndcY + 1.0f) * 0.5f * viewport.height;return screenPos;
}Vec3 Camera::unproject(const Vec3& src) const
{Vec3 dst;unproject(Director::getInstance()->getWinSize(), &src, &dst);return dst;
}Vec3 Camera::unprojectGL(const Vec3& src) const
{Vec3 dst;unprojectGL(Director::getInstance()->getWinSize(), &src, &dst);return dst;
}void Camera::unproject(const Size& viewport, const Vec3* src, Vec3* dst) const
{CCASSERT(src && dst, "vec3 can not be null");Vec4 screen(src->x / viewport.width, ((viewport.height - src->y)) / viewport.height, src->z, 1.0f);screen.x = screen.x * 2.0f - 1.0f;screen.y = screen.y * 2.0f - 1.0f;screen.z = screen.z * 2.0f - 1.0f;getViewProjectionMatrix().getInversed().transformVector(screen, &screen);if (screen.w != 0.0f){screen.x /= screen.w;screen.y /= screen.w;screen.z /= screen.w;}dst->set(screen.x, screen.y, screen.z);
}void Camera::unprojectGL(const Size& viewport, const Vec3* src, Vec3* dst) const
{CCASSERT(src && dst, "vec3 can not be null");Vec4 screen(src->x / viewport.width, src->y / viewport.height, src->z, 1.0f);screen.x = screen.x * 2.0f - 1.0f;screen.y = screen.y * 2.0f - 1.0f;screen.z = screen.z * 2.0f - 1.0f;getViewProjectionMatrix().getInversed().transformVector(screen, &screen);if (screen.w != 0.0f){screen.x /= screen.w;screen.y /= screen.w;screen.z /= screen.w;}dst->set(screen.x, screen.y, screen.z);
}bool Camera::isVisibleInFrustum(const AABB* aabb) const
{if (_frustumDirty){_frustum.initFrustum(this);_frustumDirty = false;}return !_frustum.isOutOfFrustum(*aabb);
}float Camera::getDepthInView(const Mat4& transform) const
{Mat4 camWorldMat = getNodeToWorldTransform();const Mat4 &viewMat = camWorldMat.getInversed();float depth = -(viewMat.m[2] * transform.m[12] + viewMat.m[6] * transform.m[13] + viewMat.m[10] * transform.m[14] + viewMat.m[14]);return depth;
}void Camera::setDepth(int8_t depth)
{if (_depth != depth){_depth = depth;if (_scene){//notify scene that the camera order is dirty_scene->setCameraOrderDirty();}}
}void Camera::onEnter()
{if (_scene == nullptr){auto scene = getScene();if (scene){setScene(scene);}}Node::onEnter();
}void Camera::onExit()
{// remove this camera from scenesetScene(nullptr);Node::onExit();
}// 设置成当前的场景，把之前的场景删除掉，并且把自己加入到场景的照相机当中
void Camera::setScene(Scene* scene)
{if (_scene != scene){//remove old sceneif (_scene){auto& cameras = _scene->_cameras;auto it = std::find(cameras.begin(), cameras.end(), this);if (it != cameras.end())cameras.erase(it);_scene = nullptr;}//set new sceneif (scene){_scene = scene;auto& cameras = _scene->_cameras;auto it = std::find(cameras.begin(), cameras.end(), this);if (it == cameras.end()){_scene->_cameras.push_back(this);//notify scene that the camera order is dirty_scene->setCameraOrderDirty();}}}
}void Camera::clearBackground()
{if (_clearBrush){_clearBrush->drawBackground(this);}
}void Camera::setFrameBufferObject(experimental::FrameBuffer *fbo)
{CC_SAFE_RETAIN(fbo);CC_SAFE_RELEASE_NULL(_fbo);_fbo = fbo;if(_scene){_scene->setCameraOrderDirty();}
}void Camera::applyFrameBufferObject()
{if(nullptr == _fbo){experimental::FrameBuffer::applyDefaultFBO();}else{_fbo->applyFBO();}
}void Camera::apply()
{applyFrameBufferObject();applyViewport();
}void Camera::applyViewport()
{if(nullptr == _fbo){glViewport(getDefaultViewport()._left, getDefaultViewport()._bottom, getDefaultViewport()._width, getDefaultViewport()._height);}else{glViewport(_viewport._left * _fbo->getWidth(), _viewport._bottom * _fbo->getHeight(),_viewport._width * _fbo->getWidth(), _viewport._height * _fbo->getHeight());}}int Camera::getRenderOrder() const
{int result(0);if(_fbo){result = _fbo->getFID()<<8;}else{result = 127 <<8;}result += _depth;return result;
}void Camera::visit(Renderer* renderer, const Mat4 &parentTransform, uint32_t parentFlags)
{_viewProjectionUpdated = _transformUpdated;return Node::visit(renderer, parentTransform, parentFlags);
}void Camera::setBackgroundBrush(CameraBackgroundBrush* clearBrush)
{CC_SAFE_RETAIN(clearBrush);CC_SAFE_RELEASE(_clearBrush);_clearBrush = clearBrush;
}bool Camera::isBrushValid()
{return _clearBrush != nullptr && _clearBrush->isValid();
}

暂时就这些。