cesium primitive 移动缩放旋转矩阵

本文主要是介绍cesium primitive 移动缩放旋转矩阵，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

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 localToWorld_Matrix = Cesium.Transforms.eastNorthUpToFixedFrame(origin);
let worldToLocal_Matrix = Cesium.Matrix4.inverse(localToWorld_Matrix, new Cesium.Matrix4);let scaleMatrix = Cesium.Matrix4.fromScale(new Cesium.Cartesian3(2, 1, 1));let localScaleMatrix = Cesium.Matrix4.multiply(scaleMatrix, worldToLocal_Matrix, new Cesium.Matrix4);
let worldMatrix = Cesium.Matrix4.multiply(localToWorld_Matrix, localScaleMatrix, new Cesium.Matrix4);polygonPrimitive.modelMatrix = worldMatrix;