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基于HT的CSG功能构建HTML5的3D书架

构造实体几何CSG全称Constructive solid geometry,是3D计算机图形学中构建模型的常用技术,可通过合并Union、相减Subtraction和相交Intersction的三种取集的逻辑运算,将立方体、圆柱体和棱柱等简单的基础模型,嵌套组合成更复杂三维模型。

CSG的算法这些年来已有各种语言平台版本实现,C++版主流的是 http://opencsg.org/ 已有众多基于该开源类库的应用案例,JavaScript语言较早版实现 http://evanw.github.io/csg.js/ 影响较广,很多其他js衍生版都是基于该版本进行改进完善,包括Java版的实现 https://github.com/miho/JCSG ,可参考基于JavaFX的3D打印IDE https://github.com/miho/JFXScad ,提起JavaFX视乎这些年完全消失在程序员视野毫无声息,但还是有一群拥护者持续在使用着如今地位有点尴尬的JavaFX。

技术分享

回到我们今天要搞的3D书架例子,我们将基于HT for Web的3D引擎来实现,HT已经内置了CSG功能的模型封装,我们通过构建CSGNode图元对象,该类型图元可对Host吸附的图元进行CSG技术的合集、并集和补集的三种操作,一般运用中裁剪的方式较为常用,因此CSGNode默认对Host图元的操作就是裁剪。

上图的例子效果可看出我们构建了一个DataModel数据模型,该模型绑定了一个TreeView树组件和两个Graph3dView的三维组件,上部分的Graph3dView组件添加了VisibleFunc的可见过滤器,隐藏了如下部分的Graph3dView中蓝色立方体图元,这些蓝色立方体图元就是CSGNode,其作用就是用来裁剪其吸附的书架Shelf对象,因此一般在3D编辑器状态下才需要出现,运行时科如上部分Graph3dView组件那样,通过添加可见过滤器将其隐藏,这样就实现了有凹槽可摆放书籍内容的3D书架效果,本例我们作为示例仅放了一本《CSS3  The Missing Manual》,这本书其实是由一个六面体,front面显示了书籍贴图,然后旋转一定角度进行摆放,btw《CSS3  The Missing Manual》第三版是本很不错的CSS书籍,强烈推荐!

技术分享

书架两边分别摆放了两个不同风格的小书台,通过上图我拖拽改变了蓝色CSGNode图元的位置,大家通过两张图的对比能更直观的体会到CSG的操作效果,玻璃门开关以及相册效果都是直接利用HT for Web的3D引擎提供的模型,通过设置透明度、相片贴图和旋转动画等呢只功能参数即可。

以下是该HT for Web的3D例子的所有JavaScript代码供参考:http://v.youku.com/v_show/id_XODU2MTQ4NjI4.html

ht.Default.setImage(‘ben12‘, {    width: 100,    height: 50,    comps: [        {            type: ‘image‘,            name: ‘ben1‘,            rect: [0, 0, 50, 50]        },        {            type: ‘image‘,            name: ‘ben2‘,            rect: [50, 0, 50, 50]        }    ]                });                        function init(){                                     dm = new ht.DataModel();                    treeView = new ht.widget.TreeView(dm);                                                                                                     gv1 = new ht.graph3d.Graph3dView(dm);       gv2 = new ht.graph3d.Graph3dView(dm);       splitView = new ht.widget.SplitView(gv1, gv2, ‘v‘, 0.6);       mainSplit = new ht.widget.SplitView(treeView, splitView, ‘h‘, 0.27);           view = mainSplit.getView();      view.className = ‘main‘;    document.body.appendChild(view);        window.addEventListener(‘resize‘, function (e) {        mainSplit.invalidate();    }, false);                               gv1.setMoveStep(30);    gv1.setGridVisible(true);     gv1.setEye(0, 100, 1000);    gv1.setCenter(0, 200, 0);    gv1.pan(0, 100, true);    gv1.getLabel = function(){        return null;    };    gv1.getBrightness = function(data){        return null;    };    gv1.setVisibleFunc(function(data){        if(data.showMe){            return true;        }        if(data instanceof ht.CSGNode && data.getHost()){            return false;        }        return true;    });        gv2.setMoveStep(30);    gv2.setEditable(true);    gv2.setGridVisible(true);     gv2.setEditable(true);    gv2.pan(0, 200, true);    gv2.getLabel = function(){        return null;    };                        initShelf1();                           initShelf2();                           initShelf3();                               treeView.expandAll();        var angle = 0;    setInterval(function(){        angle += Math.PI/40;        earth.r3(0, angle, 0);        photos.s(‘dw.angle‘, angle);    }, 50);                 }            function initShelf1(){    var shelf = new ht.CSGNode();    shelf.s3(500, 400, 120);    shelf.p3(0, 200, 0);    shelf.setName(‘shelf1‘);    shelf.s({        ‘all.color‘: ‘#E5BB77‘    });    dm.add(shelf);        for(var i=0; i<2; i++){        for(var j=0; j<5; j++){            var clipNode = new ht.CSGNode();            clipNode.setHost(shelf);            clipNode.s3(80, 100, 120);            clipNode.p3(-200+j*100, 340-i*120, 20);            clipNode.setName(‘substract-‘+i+‘-‘+j);            clipNode.s(‘batch‘, ‘tt‘);            clipNode.setParent(shelf);            dm.add(clipNode);        }    }        var leftNode = new ht.CSGNode();    leftNode.setHost(shelf);    leftNode.s3(23, 380, 100);    leftNode.p3(-255, 200, 0);    leftNode.setName(‘substract left‘);    leftNode.setParent(shelf);    dm.add(leftNode);        var rightNode = new ht.CSGNode();    rightNode.setHost(shelf);    rightNode.s3(23, 380, 100);    rightNode.p3(255, 200, 0);    rightNode.setName(‘substract right‘);    rightNode.setParent(shelf);    dm.add(rightNode);        var bottomNode = new ht.CSGNode();    bottomNode.setHost(shelf);    bottomNode.s3(480, 140, 140);    bottomNode.p3(0, 80, 0);    bottomNode.setName(‘substract bottom‘);    bottomNode.setParent(shelf);    dm.add(bottomNode);          var topNode = new ht.CSGNode();    topNode.setHost(shelf);    topNode.s3(480, 10, 100);    topNode.p3(0, 400, 0);    topNode.setName(‘union top‘);    topNode.s(‘attach.operation‘, ‘union‘);    topNode.setParent(shelf);    dm.add(topNode);          var book = new ht.Node();    book.setName(‘CSS3: The Missing Manual‘);    book.s3(60, 80, 8);    book.p3(-100, 210, 20);    book.r3(-Math.PI/6, Math.PI/5, 0);    book.setIcon(‘book‘);    book.s({        ‘front.image‘: ‘book‘,        ‘back.color‘: ‘white‘,        ‘left.color‘: ‘white‘,        ‘all.color‘: ‘gray‘    });    book.setHost(shelf);    book.setParent(shelf);    dm.add(book);                                    }function initShelf2(){                    var shelf = new ht.CSGNode();    shelf.s3(120, 240, 120);    shelf.p3(0, 120, 0);    shelf.setName(‘shelf2‘);    shelf.s({        ‘all.color‘: ‘#805642‘,        ‘csg.color‘: ‘yellow‘,        ‘csg.reverse.flip‘: true    });    dm.add(shelf);        var clipNode = new ht.CSGNode();    clipNode.setName(‘shelf2-substract-up‘);    clipNode.s3(100, 100, 130);    clipNode.p3(0, 180, 0);    clipNode.setHost(shelf);    clipNode.s(‘attach.cull‘, true);    clipNode.setParent(shelf);    dm.add(clipNode);        clipNode = new ht.CSGBox();    clipNode.setName(‘CSGBox-Expand-Left‘);    clipNode.s3(100, 100, 120);    clipNode.p3(0, 65, 0.1);    clipNode.setHost(shelf);    clipNode.showMe = true;    clipNode.s({        ‘all.visible‘: false,        ‘front.visible‘: true,        ‘front.toggleable‘: true,                            ‘front.reverse.flip‘: true,        ‘front.transparent‘: true,        ‘front.end‘: Math.PI * 0.7,        ‘front.color‘: ‘rgba(0, 50, 50, 0.7)‘    });    clipNode.setParent(shelf);    clipNode.setFaceExpanded(‘front‘, true, true);    dm.add(clipNode);                        earth = new ht.Node();    earth.setName(‘earth‘);    earth.setIcon(‘earth‘);    earth.s3(70, 70, 70);    earth.p3(0, 50, 0);    earth.s({        ‘shape3d‘: ‘sphere‘,        ‘shape3d.image‘: ‘earth‘    });    earth.setHost(shelf);      earth.setParent(shelf);    dm.add(earth);        shelf.t3(-360, 0, 50);    shelf.r3(0, Math.PI/7, 0);                               }            function initShelf3(){                    var shelf = new ht.CSGNode();    shelf.s3(120, 240, 120);    shelf.p3(0, 120, 0);    shelf.setName(‘shelf3‘);    shelf.setIcon(‘ben‘);    shelf.s({        ‘all.image‘: ‘brick‘,        ‘all.uv.scale‘: [2, 4],        ‘top.uv.scale‘: [2, 2],        ‘bottom.uv.scale‘: [2, 2],                                                                     ‘csg.image‘: ‘ben‘,        ‘csg.blend‘: ‘yellow‘    });    dm.add(shelf);        photos = new ht.DoorWindow();    photos.setName(‘DoorWindow-Photos‘);    photos.setIcon(‘ben12‘);    photos.s3(110, 100, 130);    photos.p3(5, 180, 0);                    photos.setHost(shelf);      photos.showMe = true;    photos.s({                            ‘bottom.uv‘: [1,1, 1,0, 0,0, 0,1],        ‘bottom.uv.scale‘: [1, 1],        ‘left.uv.scale‘: [3, 3],        ‘top.uv.scale‘: [2, 2],        ‘dw.s3‘: [0.8, 0.9, 0.05],        ‘dw.t3‘: [0, -5, 0],        ‘dw.axis‘: ‘v‘,        ‘dw.toggleable‘: false,        ‘front.image‘: ‘ben1‘,        ‘back.image‘: ‘ben2‘,        ‘all.color‘: ‘#F8CE8B‘    });    photos.setParent(shelf);    dm.add(photos);        var clipNode = new ht.CSGBox();    clipNode.setName(‘CSGBox-Expand-Top‘);    clipNode.s3(100, 100, 120);    clipNode.p3(0, 65, 0.1);    clipNode.setHost(shelf);    clipNode.showMe = true;    clipNode.s({                            ‘all.visible‘: false,        ‘front.visible‘: true,        ‘front.color‘: ‘red‘,        ‘front.transparent‘: true,        ‘front.opacity‘: 0.7,                            ‘front.reverse.flip‘: true,        ‘front.toggleable‘: true,                                                ‘front.axis‘: ‘top‘,        ‘front.end‘: Math.PI * 0.4    });    clipNode.setParent(shelf);    clipNode.setFaceExpanded(‘front‘, true, true);    dm.add(clipNode);                                        shelf.t3(360, 0, 50);    shelf.r3(0, -Math.PI/7, 0);                  }   

 

基于HT的CSG功能构建HTML5的3D书架