How to use the @here/harp-materials.CopyMaterial function in @here/harp-materials

* visible.
 */
export class LowResRenderPass extends Pass {
    private m_renderTarget: THREE.WebGLRenderTarget | null = null;
    private readonly m_localCamera: THREE.OrthographicCamera = new THREE.OrthographicCamera(
        -1,
        1,
        1,
        -1,
        0,
        1
    );
    private readonly m_quadScene: THREE.Scene = new THREE.Scene();
    private readonly m_quadUniforms: { [uniformName: string]: THREE.IUniform } =
        CopyShader.uniforms;
    private readonly m_quadMaterial: THREE.ShaderMaterial = new CopyMaterial(this.m_quadUniforms);
    private readonly m_quad: THREE.Mesh = new THREE.Mesh(
        new THREE.PlaneBufferGeometry(2, 2),
        this.m_quadMaterial
    );
    private m_pixelRatio: number | undefined;
    private m_savedWidth = 0;
    private m_savedHeight = 0;

    /**
     * The constructor for `LowResRenderPass`. It builds an internal scene with a camera looking at
     * a quad.
     *
     * @param lowResPixelRatio The `pixelRatio` determines the resolution of the internal
     *  `WebGLRenderTarget`. Values between 0.5 and `window.devicePixelRatio` can be tried to give
     * good results. A value of `undefined` disables the low res render pass. The value should not
     * be larger than`window.devicePixelRatio`.