cesium入門（七）

可視空間資料

• 3D貼圖支援開源的幾種模型還有CAD，BIM，點雲，相機模型這幾種模型的互動。
• 有時候模型可能有偏差，這時我們可以自己修改每個點的模型值，最好是傳入一個轉換矩陣這樣的會就會進行一次全新的變換

/ Adjust the tileset height so its not floating above terrain
var heightOffset = -32;
city.readyPromise.then(function(tileset) {
    // Position tileset
    var boundingSphere = tileset.boundingSphere
 
;
    var cartographic = Cesium.Cartographic.fromCartesian(boundingSphere.center);
    var surface = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0.0);
    var offset = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, heightOffset);
    var translation = Cesium.Cartesian
 
3.subtract(offset, surface, new Cesium.Cartesian3());
    tileset.modelMatrix = Cesium.Matrix4.fromTranslation(translation);
});

• 常見的貼圖風格可以參考https://github.com/AnalyticalGraphicsInc/3d-tiles/tree/master/Styling

3D模型的載入

• cesium支援新型的模型格式glTF，現在支援到2.0，同樣也提供怎麼通過私有的api把載入模型，以及其它格式到glTF的轉換操作

var
 
 scene = viewer.scene; 
var modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(
    Cesium.Cartesian3.fromDegrees(-75.62898254394531, 40.02804946899414, 0.0));
var model = scene.primitives.add(Cesium.Model.fromGltf({
    url : '../../SampleData/models/CesiumGround/Cesium_Ground.gltf',
    modelMatrix : modelMatrix,
    scale : 200.0
}));

• 同樣我可播放glTF的動畫如下

Cesium.when(model.readyPromise).then(function(model) {
    model.activeAnimations.addAll({
        loop : Cesium.ModelAnimationLoop.REPEAT，
         speedup : 0.5,
    reverse : true
    });
});

• 拾取不太懂

var handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
handler.setInputAction(
    function (movement) {
        var pick = scene.pick(movement.endPosition);
        if (Cesium.defined(pick) && Cesium.defined(pick.node) && Cesium.defined(pick.mesh)) {
            console.log('node: ' + pick.node.name + '. mesh: ' + pick.mesh.name);
        }
    },
    Cesium.ScreenSpaceEventType.MOUSE_MOVE
);