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 shaderlong 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; } //override virtual 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 to Mat4 _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 flag mutable Frustum _frustum; // camera frustum mutable 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 depth static Camera* _visitingCamera; CameraBackgroundBrush* _clearBrush; //brush used to clear the back ground experimental::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 camera auto 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 scene setScene(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 scene if (_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 scene if (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。