lerp(propertyStr) {
        const prop = this.interpolation[propertyStr];
        if (prop !== null) {
            this[propertyStr] = this.intLerp(this[propertyStr], prop, this.opt.lerpSpeed);
            if (this[propertyStr] - prop === 0) {
                this.interpolation[propertyStr] = null;
            }
        }
        return this[propertyStr];
    }
Interpolate a property to the value found in this.interpolation