使用Javascript訪問動態對象屬性

Question

我是一名使用Javascript編寫的OpenJScad構建3D模型的新手程序員。

我想弄清楚如何構建我的代碼，以便我可以訪問一個對象的實例屬性，這是用用戶輸入參數動態創建的。我有以下變量父類齒輪...

// Gear parent class 
Gear = function(numTeeth, circularPitch, pressureAngle, clearance, thickness) 
{  
var pitchRadius = numTeeth * circularPitch/(2 * Math.PI); 

我提出幾個齒輪子類，接受用戶的參數，即...

// Spur Gear 
function makeSpur(params) 
{ 
    var gear = new Gear(
    params.spurTeeth, 
    params.circularPitch, 
    params.pressureAngle, 
    params.clearance, 
    params.inputBore 
); 

if(params.inputBore > 0) 
{ 
    var inputBore = CSG.cylinder({start: [0,0,-params.thickness2], end: 
     [0,0,params.thickness2], radius: params.inputBore, resolution: 16}); 
    gear = gear.subtract(inputBore).rotateX(90); 
} 
return gear; 

...，然後動態生成位置座標。根據另一個齒輪對象的pitchRadius財產...

// function main 
var spurGear = makeSpur(params); 
spurGear = spurGear.translate([-pinionGear.pitchRadius,0,0]); 

呈現的一切，除了當我嘗試從另一個齒輪例如訪問pitchRadius屬性。我讀過關於原型和訪問私有/公共屬性，但我無法弄清楚如何構造代碼，以便我可以在main函數中訪問實例屬性。

Answer 1

下面是完整的代碼...

include("gears.jscad"); 

// Here we define the user editable parameters: 
function getParameterDefinitions() { 
    return [ 
    { name: 'circularPitch', caption: 'Circular pitch:', type: 'float', initial: 5 }, 
    { name: 'pressureAngle', caption: 'Pressure angle:', type: 'float', initial: 20 }, 
    { name: 'clearance', caption: 'Clearance:', type: 'float', initial: 0 }, 
    { name: 'thickness', caption: 'Thickness of transmission gears:', type: 'float', initial: 5 }, 
    { name: 'spurTeeth', caption: 'Number of spur teeth:', type: 'int', initial: 32 }, 
    { name: 'pinionTeeth', caption: 'Number of pinion teeth:', type: 'int', initial: 14 }, 
    { name: 'bore', caption: 'Radius of shaft:', type: 'float', initial: 5 } 
    ]; 
} 

// Main function 
function main(params) 
{ 
    // declare parts 
    spurGear = new makeSpur(params); 
    pinionGear = new makePinion(params); 

    // assemble parts 
    spurGear = spurGear.translate([-pinionGear.pitchRadius, 0, -20]); // BREAKS CODE 
    pinionGear = pinionGear.translate([-spurGear.pitchRadius, 0, 20]); // BREAKS CODE 

    return [spurGear,pinionGear]; 
} 

// Spur Gear 
function makeSpur(params) 
{ 
    var gear = new involuteGear(
    params.spurTeeth, 
    params.circularPitch, 
    params.pressureAngle, 
    params.clearance, 
    params.thickness, 
    params.bore 
); 
    if(params.bore > 0) 
    { 
    var bore = CSG.cylinder({start: [0,0,-params.thickness], end: [0,0,params.thickness], radius: params.bore, resolution: 16}); 
    gear = gear.subtract(bore).rotateX(90); 
    } 
    return gear; 
} 

// Pinion Gear 
function makePinion(params) 
{ 
    var gear = new involuteGear(
    params.pinionTeeth, 
    params.circularPitch, 
    params.pressureAngle, 
    params.clearance, 
    params.thickness, 
    params.bore 
); 
    if(params.bore > 0) 
    { 
    var bore = CSG.cylinder({start: [0,0,-params.thickness], end: [0,0,params.thickness], radius: params.bore, resolution: 16}); 
    gear = gear.subtract(bore).rotateX(90); 
    } 
    return gear; 
} 

// title: Gear 
// author: Joost Nieuwenhuijse 
// license: MIT License 

/* 
    For gear terminology see: 
    http://www.astronomiainumbria.org/advanced_internet_files/meccanica/easyweb.easynet.co.uk/_chrish/geardata.htm 
    Algorithm based on: 
    http://www.cartertools.com/involute.html 

    circularPitch: The distance between adjacent teeth measured at the pitch circle 
*/ 
function involuteGear(numTeeth, circularPitch, pressureAngle, clearance, thickness) 
{ 
    // default values: 
    if(arguments.length < 3) pressureAngle = 20; 
    if(arguments.length < 4) clearance = 0; 
    if(arguments.length < 4) thickness = 1; 

    var addendum = circularPitch/Math.PI; 
    var dedendum = addendum + clearance; 

    // radiuses of the 4 circles: 
    this.pitchRadius = numTeeth * circularPitch/(2 * Math.PI); 
    // this.getpitchRadius = function() { 
    //return pitchRadius; 
    //}; 
    var baseRadius = this.pitchRadius * Math.cos(Math.PI * pressureAngle/180); 
    var outerRadius = this.pitchRadius + addendum; 
    var rootRadius = this.pitchRadius - dedendum; 

    var maxtanlength = Math.sqrt(outerRadius*outerRadius - baseRadius*baseRadius); 
    var maxangle = maxtanlength/baseRadius; 

    var tl_at_pitchcircle = Math.sqrt(this.pitchRadius*this.pitchRadius - baseRadius*baseRadius); 
    var angle_at_pitchcircle = tl_at_pitchcircle/baseRadius; 
    var diffangle = angle_at_pitchcircle - Math.atan(angle_at_pitchcircle); 
    var angularToothWidthAtBase = Math.PI/numTeeth + 2*diffangle; 

    // build a single 2d tooth in the 'points' array: 
    var resolution = 5; 
    var points = [new CSG.Vector2D(0,0)]; 
    for(var i = 0; i <= resolution; i++) 
    { 
    // first side of the tooth: 
    var angle = maxangle * i/resolution; 
    var tanlength = angle * baseRadius; 
    var radvector = CSG.Vector2D.fromAngle(angle);  
    var tanvector = radvector.normal(); 
    var p = radvector.times(baseRadius).plus(tanvector.times(tanlength)); 
    points[i+1] = p; 

    // opposite side of the tooth: 
    radvector = CSG.Vector2D.fromAngle(angularToothWidthAtBase - angle);  
    tanvector = radvector.normal().negated(); 
    p = radvector.times(baseRadius).plus(tanvector.times(tanlength)); 
    points[2 * resolution + 2 - i] = p; 
    } 

    // create the polygon and extrude into 3D: 
    var tooth3d = new CSG.Polygon2D(points).extrude({offset: [0, 0, thickness]}); 

    var allteeth = new CSG(); 
    for(var j = 0; j < numTeeth; j++) 
    { 
    var ang = j*360/numTeeth; 
    var rotatedtooth = tooth3d.rotateZ(ang); 
    allteeth = allteeth.unionForNonIntersecting(rotatedtooth); 
    } 

    // build the root circle: 
    points = []; 
    var toothAngle = 2 * Math.PI/numTeeth; 
    var toothCenterAngle = 0.5 * angularToothWidthAtBase; 
    for(var k = 0; k < numTeeth; k++) 
    { 
    var angl = toothCenterAngle + k * toothAngle; 
    var p1 = CSG.Vector2D.fromAngle(angl).times(rootRadius); 
    points.push(p1); 
    } 

    // create the polygon and extrude into 3D: 
    var rootcircle = new CSG.Polygon2D(points).extrude({offset: [0, 0, thickness]}); 

    var result = rootcircle.union(allteeth); 

    // center at origin: 
    result = result.translate([0, 0, -thickness/2]); 

    return result; 
} 

Answer 2

我注意到，你實際上是在構造函數返回CSG對象，所以儘量使用OpenJSCAD用戶指南描述性的容器。根據指南屬性變量是爲了存儲對象的元數據。

這是指導一個例子：

var cube = CSG.cube({radius: 1.0}); 
cube.properties.aCorner = new CSG.Vector3D([1, 1, 1]); 

附加註釋：

1. 你在你的構造
2. 那麼這個返回不同的對象。如果你會做這樣的事情：齒輪= gear.rotateX（90）;那麼你有新的對象
3. 如果你將使用屬性，那麼當你做轉換時，元數據被克隆。