我正在尝试更新Cesium几何实例的颜色。我目前在javascript中使用代码但是当我将其转换为dart时,它不再有效。当我尝试更改颜色时的结果是半透明(在PerInstanceColorAppearance中)设置为false时为黑色圆圈,如果半透明设置为true则不显示任何内容。我认为这与我的飞镖转换有关,但我无法确定问题所在。
这是正确运行的javascript代码:
var primitive;
<script>
document.getElementById("test").onclick = function() {myFunction()};
function myFunction() {
var attributes = primitive.getGeometryInstanceAttributes('circle');
attributes.color = Cesium.ColorGeometryInstanceAttribute.toValue(Cesium.Color.fromRandom({alpha : 1.0}));
}
</script>
<script>
var viewer = new Cesium.Viewer('cesiumContainer');
var scene = viewer.scene;
var circleInstance = new Cesium.GeometryInstance({
geometry : new Cesium.CircleGeometry({
center : Cesium.Cartesian3.fromDegrees(-95.0, 43.0),
radius : 250000.0,
vertexFormat : Cesium.PerInstanceColorAppearance.VERTEX_FORMAT
}),
attributes : {
color : Cesium.ColorGeometryInstanceAttribute.fromColor(new Cesium.Color(1.0, 0.0, 0.0, 0.5))
},
id: 'circle'
});
primitive = new Cesium.Primitive({geometryInstances : circleInstance,
releaseGeometryInstances : false,
appearance : new Cesium.PerInstanceColorAppearance({
translucent : false,
closed : true})});
scene.primitives.add(primitive);
</script>
这是我对dart的转换:
var testPrimitive;
bool myTest = false;
void drawTestCircle() {
if(!myTest) {
var scene = _viewer['scene'];
var color = new JsObject(context['Cesium']['Color'], [1.0, 0.0, 0.0, 0.5]);
var colorInstance = context['Cesium']['ColorGeometryInstanceAttribute'].callMethod('fromColor', [color]);
var vertexFormat = context['Cesium']['PerInstanceColorAppearance']['VERTEX_FORMAT'];
var center = context['Cesium']['Cartesian3'].callMethod('fromDegrees', [-95.0, 43.0]);
var geometry = new JsObject(context['Cesium']['CircleGeometry'],
[new JsObject.jsify({'center' : center,
'radius' : 250000.0,
'vertexFormat' : vertexFormat})]);
var circleInstance = new JsObject(context['Cesium']['GeometryInstance'],
[new JsObject.jsify({'geometry' : geometry,
'attributes' : new JsObject.jsify({'color' : colorInstance}),
'id' : 'circle'})]);
var appearance = new JsObject(context['Cesium']['PerInstanceColorAppearance'],
[new JsObject.jsify({'translucent' : false, 'closed' : true})]);
testPrimitive = new JsObject(context['Cesium']['Primitive'],
[new JsObject.jsify({'geometryInstances' : circleInstance,
'releaseGeometryInstances' : true,
'appearance' : appearance})]);
scene['primitives'].callMethod('add', [testPrimitive]);
myTest = true;
} else {
var attributes = testPrimitive.callMethod('getGeometryInstanceAttributes', ['circle']);
var color = context['Cesium']['Color'].callMethod('fromRandom', [new JsObject.jsify({'alpha' : 1.0})]);
attributes['color'] = context['Cesium']['ColorGeometryInstanceAttribute'].callMethod('toValue', [color]);
}
}
在“测试”按钮上单击调用drawTestCircle。我在Cesium上使用的示例代码可以在“更新每个实例属性”下找到http://cesiumjs.org/2013/11/04/Geometry-and-Appearances/。最初我认为它与在绘制之后尝试访问testPrimitive有关,但我相信设置“releaseGeometryInstances”应该允许我操作它。任何想法或建议将不胜感激。