input/controls improvements

* add exposure parameter

* add missing uniform

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Co-authored-by: David Sehnal <dsehnal@users.noreply.github.com>

* better marking identify

* changelog

* tweak

* type tweak

* simplify ui mouse move handling

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Co-authored-by: Alexander Rose <alexander.rose@weirdbyte.de>

Dpoit avoid alpha 0 rendering

Post-processing improvements