cesium primitive 移动缩放旋转矩阵

旋转参考：cesium 指定点旋转rectangle Primitive方式矩阵篇-CSDN博客

平移参考：cesium 调整3dtiles的位置世界坐标下相对坐标下平移矩阵-CSDN博客

一、primitive方式添加polygon

let polygonInstance = new Cesium.GeometryInstance({geometry: Cesium.PolygonGeometry.fromPositions({positions: Cesium.Cartesian3.fromDegreesArray([...p1,p2[0], p1[1],...p2,p1[0], p2[1]]),height: 0,vertexFormat: Cesium.EllipsoidSurfaceAppearance.VERTEX_FORMAT}),attributes: {color: Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.fromCssColorString('#00ff00').withAlpha(0.5))}});let polygonPrimitive = new Cesium.Primitive({geometryInstances: [polygonInstance],undisplayable: true,appearance: new Cesium.PerInstanceColorAppearance({flat: true,translucent: false})});viewer.scene.primitives.add(polygonPrimitive);

二、平移

以p1为原点，将p1移动到（113.392209, 38.095546），其他几个点相对p1移动

let origin = Cesium.Cartesian3.fromDegrees(...p1);let offset = Cesium.Cartesian3.fromDegrees(113.392209, 38.095546);let translate = Cesium.Cartesian3.subtract(offset,origin,new Cesium.Cartesian3());polygonPrimitive.modelMatrix = Cesium.Matrix4.fromTranslation(translate)

三、缩放

以p1为原点，在x轴方向缩放2倍大小

let origin = Cesium.Cartesian3.fromDegrees(...p1);let localMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(origin);let inverseMatrix = Cesium.Matrix4.inverse(localMatrix, new Cesium.Matrix4);let scaleMatrix = Cesium.Matrix4.fromScale(new Cesium.Cartesian3(2, 1, 1));let modelMatrix = Cesium.Matrix4.multiply(scaleMatrix, inverseMatrix, new Cesium.Matrix4);polygonPrimitive.modelMatrix = Cesium.Matrix4.multiply(localMatrix, modelMatrix, new Cesium.Matrix4);