lerpColors( color1, color2, alpha ) {

		this.r = color1.r + ( color2.r - color1.r ) * alpha;
		this.g = color1.g + ( color2.g - color1.g ) * alpha;
		this.b = color1.b + ( color2.b - color1.b ) * alpha;

		return this;

	}
Linearly interpolates between the given colors and stores the result in this instance.
The alpha argument can be thought of as the ratio between the two colors, where `0.0`
is the first and `1.0` is the second color.

@param {Color} color1 - The first color.
@param {Color} color2 - The second color.
@param {number} alpha - The interpolation factor in the closed interval `[0,1]`.
@return {Color} A reference to this color.