From d61fc1e871f5df78afa1211ffa1175fdd9c2c077 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Mon, 15 Nov 2021 12:27:32 -0700
Subject: [PATCH] triggerbox: add passthru property to control input
 passthrough (monitoring)

---
 libs/ardour/ardour/triggerbox.h |  5 +++++
 libs/ardour/triggerbox.cc       | 27 +++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/libs/ardour/ardour/triggerbox.h b/libs/ardour/ardour/triggerbox.h
index 1647853d52..d6a4c52a78 100644
--- a/libs/ardour/ardour/triggerbox.h
+++ b/libs/ardour/ardour/triggerbox.h
@@ -431,6 +431,9 @@ class LIBARDOUR_API TriggerBox : public Processor
 
 	void add_midi_sidechain (std::string const & name);
 
+	bool pass_thru() const { return _pass_thru; }
+	void set_pass_thru (bool yn);
+
 	void request_reload (int32_t slot, void*);
 	void request_use (int32_t slot, Trigger&);
 
@@ -475,6 +478,7 @@ class LIBARDOUR_API TriggerBox : public Processor
 	Trigger* up_next;
 	Trigger* currently_playing;
 	std::atomic<bool> _stop_all;
+	std::atomic<bool> _pass_thru;
 
 	boost::shared_ptr<SideChain> _sidechain;
 
@@ -546,6 +550,7 @@ class LIBARDOUR_API TriggerBox : public Processor
 namespace Properties {
 	LIBARDOUR_API extern PBD::PropertyDescriptor<bool> use_follow;
 	LIBARDOUR_API extern PBD::PropertyDescriptor<bool> running;
+	LIBARDOUR_API extern PBD::PropertyDescriptor<bool> passthru;
 	LIBARDOUR_API extern PBD::PropertyDescriptor<bool> legato;
 	LIBARDOUR_API extern PBD::PropertyDescriptor<bool> quantization;
 	LIBARDOUR_API extern PBD::PropertyDescriptor<Trigger::LaunchStyle> launch_style;
diff --git a/libs/ardour/triggerbox.cc b/libs/ardour/triggerbox.cc
index ba030e018c..a539682caf 100644
--- a/libs/ardour/triggerbox.cc
+++ b/libs/ardour/triggerbox.cc
@@ -44,6 +44,7 @@ namespace ARDOUR {
 	namespace Properties {
 		PBD::PropertyDescriptor<bool> use_follow;
 		PBD::PropertyDescriptor<bool> running;
+		PBD::PropertyDescriptor<bool> passthru;
 		PBD::PropertyDescriptor<bool> legato;
 		PBD::PropertyDescriptor<bool> quantization;
 		PBD::PropertyDescriptor<Trigger::LaunchStyle> launch_style;
@@ -1321,8 +1322,10 @@ MIDITrigger::run (BufferSet& bufs, samplepos_t start_sample, samplepos_t end_sam
 void
 Trigger::make_property_quarks ()
 {
-	Properties::muted.property_id = g_quark_from_static_string (X_("running"));
+	Properties::running.property_id = g_quark_from_static_string (X_("running"));
 	DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for running = %1\n", Properties::running.property_id));
+	Properties::passthru.property_id = g_quark_from_static_string (X_("passthru"));
+	DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for passthru = %1\n", Properties::passthru.property_id));
 	Properties::legato.property_id = g_quark_from_static_string (X_("legato"));
 	DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for legato = %1\n", Properties::legato.property_id));
 	Properties::use_follow.property_id = g_quark_from_static_string (X_("use-follow"));
@@ -1376,6 +1379,7 @@ TriggerBox::TriggerBox (Session& s, DataType dt)
 	, up_next (0)
 	, currently_playing (0)
 	, _stop_all (false)
+	, _pass_thru (false)
 	, requests (1024)
 {
 
@@ -1747,6 +1751,13 @@ TriggerBox::process_midi_trigger_requests (BufferSet& bufs)
 	}
 }
 
+void
+TriggerBox::set_pass_thru (bool yn)
+{
+	_pass_thru = yn;
+	PropertyChanged (Properties::passthru);
+}
+
 void
 TriggerBox::run (BufferSet& bufs, samplepos_t start_sample, samplepos_t end_sample, double speed, pframes_t nframes, bool result_required)
 {
@@ -1827,7 +1838,19 @@ TriggerBox::run (BufferSet& bufs, samplepos_t start_sample, samplepos_t end_samp
 	Temporal::TempoMap::SharedPtr tmap (Temporal::TempoMap::use());
 	const double bpm = tmap->quarters_per_minute_at (start);
 	uint64_t max_chans = 0;
-	bool first = false;
+
+	/* if passthru is set, active triggers should always
+	 * ::accumulate_from() rather than ::read_from(). If false, then the
+	 * first active trigger uses ::read_from() and later ones will use
+	 * ::accumulate_from()
+	 *
+	 * Note that this is based on a now mostly (entirely?) unused idea of
+	 * allowing more than one trigger to operate at a time. Nevertheless
+	 * the logic is still correct even if there is only ever 1 active
+	 * trigger.
+	 */
+
+	bool first = (_pass_thru ? true : false);
 
 	/* see if there's another trigger explicitly queued that has legato set. */