Cesium实现雷达效果

目录

• 项目地址
• 实现效果
• 核心代码

项目地址

https://github.com/zhengjie9510/webgis-demo

实现效果

核心代码

var radar = scene.primitives.add(
 new Primitive({
   geometryInstances: redCone,
   appearance: new MaterialAppearance({
     // 自定义纹理
     material: new Material({
       fabric: {
         // type: "radar",
         uniforms: {
           color: new Color(0.2, 1.0, 0.0, 1.0),
           repeat: 30.0,
           offset: 0.0,
           thickness: 0.2,
         },
         source: `
           uniform vec4 color;
           uniform float repeat;
           uniform float offset;
           uniform float thickness;
           czm_material czm_getMaterial(czm_materialInput materialInput)
           {
             czm_material material = czm_getDefaultMaterial(materialInput);
             float sp = 1.0/repeat;
             vec2 st = materialInput.st;
             float dis = distance(st, vec2(0.5));
             float m = mod(dis + offset, sp);
             float a = step(sp*(1.0-thickness), m);
             material.diffuse = color.rgb;
             material.alpha = a * color.a;
             vec3 normalMC = material.normal;
             if(normalMC.y < 0.0 && normalMC.z < 0.0)
             { 
               discard;
             }
             return material;
           }`,
       },
       translucent: true,
     }),
     faceForward: false, // 当绘制的三角面片法向不能朝向视点时，自动翻转法向，从而避免法向计算后发黑等问题
     closed: true, // 是否为封闭体，实际上执行的是是否进行背面裁剪
     vertexShaderSource: `
       in vec3 position3DHigh;
       in vec3 position3DLow;
       in vec3 normal;
       in vec2 st;
       in float batchId;

       out vec3 v_positionEC;
       out vec3 v_normalEC;
       out vec2 v_st;

       void main()
       {
         vec4 p = czm_computePosition();

         v_positionEC = (czm_modelViewRelativeToEye * p).xyz;      // position in eye coordinates
         v_normalEC =  normal;                         // normal in world coordinates
         v_st = st;

         gl_Position = czm_modelViewProjectionRelativeToEye * p;
       }`,
   }),
 })
)