how to apply ElevationContour Material to the polygon entity?

CesiumJS
1

1. A concise explanation of the problem you’re experiencing.

how to apply ElevationContour Material to the polygon entity?

2. A minimal code example. If you’ve found a bug, this helps us reproduce and repair it.

var viewer = new Cesium.Viewer(‘cesiumContainer’, {

terrainProvider: Cesium.createWorldTerrain({

requestVertexNormals: true //Needed to visualize slope

})

});

var material = Cesium.Material.fromType(‘ElevationContour’);

var contourUniforms = material.uniforms;

contourUniforms.width = 2.0;

contourUniforms.spacing = 5.0;

contourUniforms.color = Cesium.Color.RED;

var scene = viewer.scene;

var instance = new Cesium.GeometryInstance({

geometry : new Cesium.RectangleGeometry({

rectangle : Cesium.Rectangle.fromDegrees(-100.0, 20.0, -90.0, 30.0),

vertexFormat : Cesium.EllipsoidSurfaceAppearance.VERTEX_FORMAT

})

});

scene.primitives.add(new Cesium.Primitive({

geometryInstances : [instance],

appearance : new Cesium.EllipsoidSurfaceAppearance({

material : material

})

}));

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.

**i want to **apply ElevationContour or ElevationRamp or SlopeRamp to the fixed region(picture1) instead of whole globe (picture2).

111.jpg
111.jpg932×705 82.7 KB

333.jpg
333.jpg714×643 27.4 KB

4. The Cesium version you’re using, your operating system and browser.

CE V 1.50

Chrome V 60

2

I think the problem is that the required vertex attributes (which are present in the terrain geometry) are not present on the rectangle geometry, so that’s why nothing is shown when applying to the rectangle.

To do that you’d have to write a custom Appearance (the best resources on that are this tutorial https://cesiumjs.org/tutorials/Geometry-and-Appearances/ and this guide https://github.com/AnalyticalGraphicsInc/cesium/wiki/Fabric ) that would mix the default GlobeFS.glsl with the slope/elevation materials, for a given area. Although it might not be a trivial change if you’re not comfortable with graphics shaders.