public function changeHsl($hueAngle = 0, $saturationFactor = 1, $luminanceFactor = 1) {
		$hueAngle /= 360;
		$this->useShader('
			$hue += $args[0];
			$saturation *= $args[1];
			$luminance *= $args[2];
		', array($hueAngle, $saturationFactor, $luminanceFactor));
		return $this;
	}