+
+ -- The commentator output has no overlay on it.
+ local extra_alpha_factor = 1.0
+ if not simple_signal_has_overlay(transition_src_signal) and
+ not simple_signal_has_overlay(transition_dst_signal) then
+ extra_alpha_factor = 0.0
+ elseif not simple_signal_has_overlay(transition_src_signal) then
+ extra_alpha_factor = tt
+ elseif not simple_signal_has_overlay(transition_dst_signal) then
+ extra_alpha_factor = 1.0 - tt
+ end
+ prepare_overlay_live(chain, t, extra_alpha_factor)