Enhancement: Lightcookies for clustered lights

[MyGamepedia]

What would this enhancement be for?

Rendering

Describe your enhancement suggestion in more detail

Ability to use texture light. Cubemap texture for point light, general texture for spot light. Here is example of how significantly it can improve visuals. Lightcookie disabled.

Lightcookie enabled (yeah, it's just texture).

In case of Portal 1/2, it mainly can be used for weighted cubes, so instead of flat light, you will see a heart-shaped light emitted by the weighted companion cube. This feature is also useful for optimization, when casting dynamic shadows is not needed, but you want to see shadows from grate. Example of such use case.

Strata also can use webm videos for projectedtexture, so you maybe can add support of it for clustered spot light (not really sure how it could be implemented for point lights).

All the features might be possible toggle with input (for every individual light) and graphics settings.