Renderer: use exposure even when tone mapping is off

[slipher]

Fixes #1628

[VReaperV]

Rename u_TonemapExposure -> u_Exposure

That seems like it can break configs if someone e. g. used it in autoexec.cfg. Is the renaming really necessary?

[illwieckz]

Rename u_TonemapExposure -> u_Exposure

That seems like it can break configs if someone e. g. used it in autoexec.cfg. Is the renaming really necessary?

This renames the internal variable, not the r_toneMappingExposure cvar.

[VReaperV]

Rename u_TonemapExposure -> u_Exposure

That seems like it can break configs if someone e. g. used it in autoexec.cfg. Is the renaming really necessary?

This renames the internal variable, not the r_toneMappingExposure cvar.

The comment says:

// TODO(0.56): rename because it can be used without tone mapping now

[illwieckz]

Ah yes. The sentence you quoted didn't mention that, and the currently proposed code doesn't do that yet.

To be honest I'm in favor of the renaming of the cvar. We are still in beta and if every first implementation is written in stone and we cannot use our experience and testing to make it better it becomes hard to do things.

As a side note I would like to have a cvar alias mechanism so using an old name sets the new cvar, but we haven't that yet.