How to listen for texture requests completion?

[linsanda]

I want to wait textrue requests completion,then set primitive.show = true

function createPriv(geoDatas,info) {
let texture = ‘http://xxxxxxxxxxxxxxx/xx.jpg’

let mat = new Cesium.Material({
    fabric: {
        type : 'Image', 
        uniforms: {
            image: texture,
        },
    },
})

result.positions = geoDatas.positions
result.uvs = geoDatas.uvs
result.indexes = geoDatas.indexes

var geometry = new Cesium.Geometry({
    attributes: {
        position: new Cesium.GeometryAttribute({
            componentDatatype: Cesium.ComponentDatatype.DOUBLE,
            componentsPerAttribute: 3,
            values: result.positions,
        }),

        st: new Cesium.GeometryAttribute({
            componentDatatype: Cesium.ComponentDatatype.FLOAT,
            componentsPerAttribute: 2,
            values: result.uvs,
        }),

    },

    indices: result.indexes,
    primitiveType: Cesium.PrimitiveType.TRIANGLES,
    boundingSphere: Cesium.BoundingSphere.fromVertices(result.positions),
});

var c = Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.BLUE);
var myInstance = new Cesium.GeometryInstance({
geometry: geometry,
    attributes: {
        color: c,
    },
    // show: new Cesium.ShowGeometryInstanceAttribute(true),
});

var priv = new Cesium.Primitive({
    shadows: Cesium.ShadowMode.ENABLED,
    geometryInstances: [myInstance],
    asynchronous: false,
    allowPicking:false,
    interleave:true,
    compressVertices:true,
    appearance: new Cesium.MaterialAppearance({
        closed: false,
        translucent: true,
        material: mat,
        vertexShaderSource: `
            attribute vec3 position3DHigh;

            attribute vec3 position3DLow;

            attribute vec4 color;

            varying vec4 v_color;

            attribute float batchId;

            attribute vec2 st;

            varying vec2 v_st;

            void main()

            {

                v_st = st;

                vec4 p = czm_computePosition();

                v_color =color;

                p = czm_modelViewProjectionRelativeToEye * p;

                gl_Position = p;

            }

        `,


        fragmentShaderSource: `  

            varying vec4 v_color;

            varying vec2 v_st;

            uniform sampler2D depthTexture;


            float almostIdentity( float x, float m, float n )

            {

                if( x>m ) return x;

                float a = 2.0*n - m;

                float b = 2.0*m - 3.0*n;

                float t = x/m;

                return (a*t + b)*t*t + n;

            }

            void main()

            {

                if(!gl_FrontFacing){

                    discard;

                }

               

                vec4 c = texture2D(image_0,v_st); 
                gl_FragColor = c;

            }

        `,

    })

});

…

}