constructor(renderer, settings) {
		this.init(renderer, settings);
	}
@param {WebGLRenderer} renderer - the current WebGL renderer session
@param {object} settings - additional settings to initialize this compositors
@param {object[]} settings.attribute - an array of attributes definition
@param {string} settings.attribute.name - name of the attribute in the vertex shader
@param {number} settings.attribute.size - number of components per vertex attribute. Must be 1, 2, 3, or 4.
@param {GLenum} settings.attribute.type - data type of each component in the array
@param {boolean} settings.attribute.normalized - whether integer data values should be normalized into a certain range when being cast to a float
@param {number} settings.attribute.offset - offset in bytes of the first component in the vertex attribute array
@param {object} settings.shader - an array of attributes definition
@param {string} settings.shader.vertex - a string containing the GLSL source code to set
@param {string} settings.shader.fragment - a string containing the GLSL source code to set