Actually, there are things called “Light Functions” you can build one with the material editor. In the attached image I created the light function material you see in the corner, in the scene it’s being projected from a SpotLight in the center of the image, the “Outer Cone Angle” controls the size that the Light Function is projected over when using a SpotLight. If it’s used on a Point Light the function is mapped spherically.
There is one Limitation though, it only works on Dynamic aka. Movable Lights.
