基于HTML5的WebGL呈现A星算法的3D可视化

jopen 5年前

基于HTML5的WebGL呈现A星算法的3D可视化

http://www.hightopo.com/demo/astar/astar.html

最近搞个游戏遇到最短路径的常规游戏问题,一时起兴基于 HT for Web 写了个A*算法的WebGL 3D呈现,算法基于开源  https://github.com/bgrins/javascript-astar 的javascript实现,其实作者也有个不错的2D例子实现  http://www.briangrinstead.com/files/astar/ ,只不过觉得所有A*算法的可视化实现都是平面的不够酷,另外还有不少参数需要调节控制,还是值得好好搞个全面的Demo,先上张2D和3D例子的对照图。

基于HTML5的WebGL呈现A星算法的3D可视化

实现代码比较容易一百多行,不过算法核心在astar.js了,界面核心在 ht.js 里面了,我只需要构建网格信息,只需监听用户点击,然后调用astar.js进行最短路径计算,将结果通过动画的方式呈现出走动的过程,所有代码如下:

function init() {        w = 40; m = 20; d = w * m / 2;       gridRows = [];          dm = new ht.DataModel();        g3d = new ht.graph3d.Graph3dView(dm);        g3d.setGridVisible(true);    g3d.setGridColor('#BBBBBB');    g3d.setGridSize(m);    g3d.setGridGap(w);       g3d.addToDOM();                              g3d.sm().setSelectionMode('none');       anim = startBall = endBall = null;          g3d.getView().addEventListener(ht.Default.isTouchable ? 'touchstart' : 'mousedown', function(e){          if(!anim){        var p = g3d.getHitPosition(e);        var x = Math.floor((p[0] + d)/ w);        var y = Math.floor((p[2] + d)/ w);        var endBall = dm.getDataByTag("cell_" + x + "_" + y);        if(endBall && endBall.s('batch') !== 'wall'){                 if(startBall.a('x') === x && startBall.a('y') === y){            return;          }                var g = new Graph(gridRows, {             diagonal: formPane.v('diagonal')           });          var start = g.grid[startBall.a('x')][startBall.a('y')];          var end = g.grid[x][y];          var result = astar.search(g, start, end, {            closest: formPane.v('closest')                 });            if(!result.length){            return;          }          x = result[result.length-1].x;          y = result[result.length-1].y;          endBall = dm.getDataByTag("cell_" + x + "_" + y);          endBall.s('3d.visible', true);          startBall.s('3d.visible', false);          formPane.setDisabled(true);          anim = ht.Default.startAnim({            duration: 700,            finishFunc: function(){                for(var i=0; i<result.length; i++){                var ball = dm.getDataByTag("cell_" + result[i].x + "_" + result[i].y);                ball.s({                  '3d.visible': false,                  'shape3d.opacity': 1,                  'shape3d.transparent': false                });                 startBall.p3(-d+w*x+w/2, w/2, -d+w*y+w/2);                startBall.a({x: x, y: y});                startBall.s('3d.visible', true);              }              anim = null;              formPane.setDisabled(false);            },            action: function(v){              var index = Math.round(v*result.length);              for(var i=0; i<index; i++){                var ball = dm.getDataByTag("cell_" + result[i].x + "_" + result[i].y);                ball.s({                  '3d.visible': true,                  'shape3d.opacity': i/index*0.3 + 0.7,                  'shape3d.transparent': true                });                       }            }          });                    }      }          }, false);             createFormPane();    createGrid();          }      function createGrid(){    dm.clear();       var ball;    gridRows.length = 0;    for(var x = 0; x < m; x++) {      var nodeRow = [];      gridRows.push(nodeRow);      for(var y = 0; y < m; y++) {                var isWall = Math.floor(Math.random()*(1/formPane.v('frequency')));        if(isWall === 0){          nodeRow.push(0);          createNode(x, y).s({            'batch': 'wall',            'all.color': '#9CA69D'          });        }else{          nodeRow.push(1);          ball = createNode(x, y).s({            'shape3d': 'sphere',              'shape3d.color': '#FF703F',            '3d.visible': false          });        }         }        }    if(!ball){      createGrid();      return;    }       startBall = createNode(ball.a('x'), ball.a('y'), 'start').s({      'shape3d': 'sphere',        'shape3d.color': '#FF703F'         });      shape = new ht.Shape();    shape.setPoints(new ht.List([      {x: -d, y: d},      {x: d, y: d},      {x: d, y: -d},      {x: -d, y: -d},      {x: -d, y: d}    ]));    shape.setThickness(4);    shape.setTall(w);    shape.setElevation(w/2);    shape.setClosePath(true);    shape.s({      'all.color': 'rgba(187, 187, 187, 0.8)',       'all.transparent': true,       'all.reverse.cull': true    });    dm.add(shape);         }  function createNode(x, y, tag){    var node = new ht.Node();    tag = tag || "cell_" + x + "_" + y;          node.setTag(tag);       node.a({ x: x,  y: y });    node.s3(w*0.9, w*0.9, w*0.9);    node.p3(-d+w*x+w/2, w/2, -d+w*y+w/2);    node.s({      'all.reverse.cull': true,      'shape3d.reverse.cull': true    });    dm.add(node);    return node;  }          function createFormPane() {         formPane = new ht.widget.FormPane();    formPane.setWidth(230);    formPane.setHeight(70);    formPane.getView().className = 'formpane';    document.body.appendChild(formPane.getView());       formPane.addRow(['Wall Frequency', {      id: 'frequency',      slider: {        min: 0,        max: 0.8,        value: 0.1,               onValueChanged: function(){          createGrid();        }      }    }], [100, 0.1]);              formPane.addRow([      {        id: 'closest',        checkBox: {          label: 'Try Closest'        }      },      {        id: 'diagonal',        checkBox: {          label: 'Allow Diagonal'        }        }    ], [0.1, 0.1]);  }

只从iOS8支持WebGL后在移动终端上测试3D应用比当前的大部分Android平板舒服多了,以上的例子在iOS系统下呈现和算法都挺流畅, http://v.youku.com/v_show/id_XODMzOTU1Njcy.html ,当然这个小例子数据量也不大,本质其实还是2D的最短路径算法,并非真正意义的3D空间最短路径,但还是足够解决很多实际应用问题了。

http://www.hightopo.com/demo/astar/astar.html

基于HTML5的WebGL呈现A星算法的3D可视化