three.js/src/textures/CompressedTexture.js

/**
 * @author alteredq / http://alteredqualia.com/
 */

THREE.CompressedTexture = function ( mipmaps, width, height, format, type, mapping, wrapS, wrapT, magFilter, minFilter, anisotropy ) {

	THREE.Texture.call( this, null, mapping, wrapS, wrapT, magFilter, minFilter, format, type, anisotropy );

	this.image = { width: width, height: height };
	this.mipmaps = mipmaps;

	// no flipping for cube textures
	// (also flipping doesn't work for compressed textures )

	this.flipY = false;

	// can't generate mipmaps for compressed textures
	// mips must be embedded in DDS files

	this.generateMipmaps = false;

};

THREE.CompressedTexture.prototype = Object.create( THREE.Texture.prototype );
THREE.CompressedTexture.prototype.constructor = THREE.CompressedTexture;

THREE.CompressedTexture.prototype.clone = function () {

	var texture = new THREE.CompressedTexture();

	THREE.Texture.prototype.copy.call( texture, this );

	return texture;

};