Babylonjs笔记——相机和粒子系统源码部分
babylonjs中arcrotateCamera和粒子系统的部分源码注释，感觉babylonjs有个不好的就是源码没有什么注释，有些变量根本就不知道是什么意思，要自己一个个试。
一。ArcRotateCamera相机构造函数中成员变量注释，没用专业名词， 全是自己的话
this.alpha = alpha;//相机绕y轴旋转的角度
this.beta = beta;//相机绕x轴旋转的角度
this.radius = radius;//视野半径
this.target = target;//目标
this.inertialAlphaOffset = 0;//绕y轴旋转偏移量
this.inertialBetaOffset = 0;//绕x轴旋转偏移量，用于限制旋转角度
this.inertialRadiusOffset = 0;//视野范围偏移量
this.lowerAlphaLimit = null;//
this.upperAlphaLimit = null;
this.lowerBetaLimit = 0.01;//
this.upperBetaLimit = Math.PI;//从y的正半轴可绕x轴旋转最大角度
this.lowerRadiusLimit = null;//视点拉近的最大距离，用于限制视野范围
this.upperRadiusLimit = null;//视点拉远的最大距离
this.angularSensibilityX = 1000.0;
this.angularSensibilityY = 1000.0;
this.wheelPrecision = 3.0;
this.pinchPrecision = 2.0;
this.panningSensibility = 50.0;//平移系数
this.inertialPanningX = 0;
this.inertialPanningY = 0;
this.keysUp = [38];
this.keysDown = [40];
this.keysLeft = [37];
this.keysRight = [39];
this.zoomOnFactor = 1;
this.targetScreenOffset = BABYLON.Vector2.Zero();
this.pinchInwards = true;
this.allowUpsideDown = true;
this._keys = [];
this._viewMatrix = new BABYLON.Matrix();
// Panning
this.panningAxis = new BABYLON.Vector3(1, 1, 0);
this._isRightClick = false;
this._isCtrlPushed = false;//ctrl键盘：ctrl+鼠标任意键为拖拽
this.checkCollisions = false;//碰撞检测
this.collisionRadius = new BABYLON.Vector3(0.5, 0.5, 0.5);//碰撞检测的半径
this._collider = new BABYLON.Collider();
this._previousPosition = BABYLON.Vector3.Zero();
this._collisionVelocity = BABYLON.Vector3.Zero();
this._newPosition = BABYLON.Vector3.Zero();
二粒子系统ParticleSystem，构造函数中的成员变量注释
this.animations = [];//动画
this.renderingGroupId = 0;
this.emitter = null;//发射器
this.emitRate = 10;//发射速率，不是粒子的速度，是粒子系统单位时间内发射多少粒子
this.manualEmitCount = -1;
this.updateSpeed = 0.01;更新速率
this.targetStopDuration = 0;
this.disposeOnStop = false;
this.minEmitPower = 1;最小发射力量
this.maxEmitPower = 1;最大发射力量
this.minLifeTime = 1;粒子的最小生命周期
this.maxLifeTime = 1;粒子的最大生命周期
this.minSize = 1;粒子的最小尺寸
this.maxSize = 1;粒子的最大尺寸
this.minAngularSpeed = 0;
this.maxAngularSpeed = 0;
this.layerMask = 0x0FFFFFFF;
this.blendMode = ParticleSystem.BLENDMODE_ONEONE;
this.forceDepthWrite = false;
this.gravity = BABYLON.Vector3.Zero();重力
this.direction1 = new BABYLON.Vector3(0, 1.0, 0);粒子的发射方向，是相对于发射器的方向！！！不是相对于场景中的方向
this.direction2 = new BABYLON.Vector3(0, 1.0, 0);粒子的发射方向2，同上
this.minEmitBox = new BABYLON.Vector3(-0.5, -0.5, -0.5);发射器中最小的发射部位；比如一个长方体的左下前角
this.maxEmitBox = new BABYLON.Vector3(0.5, 0.5, 0.5);发射器中最大的发射部分：比如长方体发射器的右（x）上（y）后(z)角
this.color1 = new BABYLON.Color4(1.0, 1.0, 1.0, 1.0);粒子的颜色
this.color2 = new BABYLON.Color4(1.0, 1.0, 1.0, 1.0);
this.colorDead = new BABYLON.Color4(0, 0, 0, 1.0);
this.textureMask = new BABYLON.Color4(1.0, 1.0, 1.0, 1.0);
this.particles = new Array();
this._vertexDeclaration = [3, 4, 4];
this._vertexStrideSize = 11 * 4; // 11 floats per particle (x, y, z, r, g, b, a, angle, size, offsetX, offsetY)
this._stockParticles = new Array();
this._newPartsExcess = 0;
this._scaledColorStep = new BABYLON.Color4(0, 0, 0, 0);
this._colorDiff = new BABYLON.Color4(0, 0, 0, 0);
this._scaledDirection = BABYLON.Vector3.Zero();
this._scaledGravity = BABYLON.Vector3.Zero();
this._currentRenderId = -1;
this._started = false;
this._stopped = false;
this._actualFrame = 0;
this.id = name;
this._capacity = capacity;粒子的数量
this._scene = scene;
this._customEffect = customEffect;