41bb0548b0
Lamps were not tagged with `ID_RECALC_SHADING` when they were updated from drivers. As a result, Cycles considered the lamp as unchanged. This is resolved by having a (seemingly non-functional) callback in a new `LIGHT_UPDATE` depsgraph node. This patch unconditionally adds the `LIGHT_UPDATE` node + the relation from the lamp's PARAMETERS node. Differential Revision: https://developer.blender.org/D7822 Reviewed by: brecht