Indirect sunlight (or filtered sunlight) diminishes the "growing power" of the sunlight - resulting in a "weaker" amount of light for that indirect period. In other words; you will get, proportionaly, less overall growth. As long as your plants receive 8 hours, or so, of direct sunlight each day they should be fine.
The threshold that cannabis takes to consider itself in "darkness" is more severe than just indirect or filtered light. The common "Rule of thumb" for considering darkness is the amount of sunlight that is reflected during a "Full Moon". All "short day" plants can tolerate the light from a full moon - but much more than that and the light will interfer with the plants "internal timer" that keeps track of night and day. So unless your indirect sunlight hours are as dark as a "FullMoon" night - you don't have anything to worry about.