onBeforeRender( renderer ) {

		const uniforms = this.material.uniforms;

		if ( uniforms && uniforms.resolution ) {

			renderer.getViewport( _viewport );
			this.material.uniforms.resolution.value.set( _viewport.z, _viewport.w );

		}

	}
Computes an array of distance values which are necessary for rendering dashed lines.
For each vertex in the geometry, the method calculates the cumulative length from the
current point to the very beginning of the line.

@return {Wireframe} A reference to this instance.