Lighting limitations on the forward renderer

Hi,

We’re building an environment using the forward renderer, and we need to animate the skydome around the player’s position. In order to do this we would need to animate the sun’s directional light.

We’re aware of the limitation currently on the forward renderer that prevents a moving light from casting dynamic shadows. Could someone explain why this limitation exists at the moment, and if it’s something that is being worked on?

Also as a follow up question, could you explain the current limitations with light functions and IES profiles, and whether or not there’s any plans for them to be supported on the forward renderer.

Thanks,

Jay

Movable lights could easily be changed to cast shadows, as long as they are packed within the same 4 channels that stationary lights are packed into. The limitation there is due to 4 channels of the light attenuation texture which is passed into the base pass.

There’s a bigger issue though, which is that all the deferred techniques used in the forward renderer (projected shadows, decals, atmosphere) don’t work properly with MSAA. This needs to be solved before you can really use dynamic shadows extensively. We’d like to solve both of these for 4.15, but time is tight.

Light functions can be made to work easily due to the already existing 4 channel light attenuation texture. IES profiles are a bit more work because they have to be atlassed so they can all be accessible from any shader. I’d like to get light functions working in 4.15, but IES profiles will probably be later.

Hi Daniel,

Thanks for getting back to me, that’s really helpful.

One of our coders is going to have a look and see what we can get away with, and whether or not the MSAA is an issue for us or not.

Cheers,

Jay