From 34789ff22f7a175a7c5214f2d80c0ea33531205d Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sun, 18 Jun 2023 22:39:45 +0200
Subject: [PATCH] LuaProc: add option to set time information

---
 libs/ardour/ardour/luaproc.h |  1 +
 libs/ardour/luaproc.cc       | 63 +++++++++++++++++++++++++++++++++++-
 share/scripts/_time_info.lua | 44 +++++++++++++++++++++++++
 3 files changed, 107 insertions(+), 1 deletion(-)
 create mode 100644 share/scripts/_time_info.lua

diff --git a/libs/ardour/ardour/luaproc.h b/libs/ardour/ardour/luaproc.h
index c6efacdb5f..9e83a5de7d 100644
--- a/libs/ardour/ardour/luaproc.h
+++ b/libs/ardour/ardour/luaproc.h
@@ -157,6 +157,7 @@ private:
 	bool _lua_does_channelmapping;
 	bool _lua_has_inline_display;
 	bool _connect_all_audio_outputs;
+	bool _set_time_info;
 
 	void queue_draw () { QueueDraw(); /* EMIT SIGNAL */ }
 	DSP::DspShm lshm;
diff --git a/libs/ardour/luaproc.cc b/libs/ardour/luaproc.cc
index c8865016e2..0b84686ffe 100644
--- a/libs/ardour/luaproc.cc
+++ b/libs/ardour/luaproc.cc
@@ -61,6 +61,7 @@ LuaProc::LuaProc (AudioEngine& engine,
 	, _lua_does_channelmapping (false)
 	, _lua_has_inline_display (false)
 	, _connect_all_audio_outputs (false)
+	, _set_time_info (false)
 	, _designated_bypass_port (UINT32_MAX)
 	, _signal_latency (0)
 	, _control_data (0)
@@ -286,6 +287,26 @@ LuaProc::load_script ()
 		}
 	}
 
+	/* parse options */
+	luabridge::LuaRef options = luabridge::getGlobal (L, "dsp_options");
+	if (options.isFunction ()) {
+		try {
+			luabridge::LuaRef opts = options ();
+			if (opts.isTable ()) {
+				for (luabridge::Iterator i (opts); !i.isNil (); ++i) {
+					if (!i.key().isString()) {
+						continue;
+					}
+					if (i.key().cast<std::string> () == "time_info" && i.value().isBoolean ()) {
+						_set_time_info = i.value().cast<bool> ();
+					}
+				}
+			}
+		} catch (...) {
+			return true;
+		}
+	}
+
 	// initialize the DSP if needed
 	luabridge::LuaRef lua_dsp_init = luabridge::getGlobal (L, "dsp_init");
 	if (lua_dsp_init.type () == LUA_TFUNCTION) {
@@ -678,6 +699,47 @@ LuaProc::connect_and_run (BufferSet& bufs,
 #endif
 
 	try {
+		lua_State* L = lua.getState ();
+
+		if (_set_time_info) {
+			using namespace Temporal;
+			TempoMap::SharedPtr tmap (TempoMap::use ());
+			const TempoMetric&  metric (tmap->metric_at (timepos_t (start)));
+			const TempoMetric&  metric_end (tmap->metric_at (timepos_t (end)));
+			const BBT_Time&     bbt (metric.bbt_at (timepos_t (start)));
+
+			luabridge::LuaRef lua_time (luabridge::newTable (L));
+
+			lua_time["sampleTime"]    = start;
+			lua_time["sampleTimeEnd"] = end;
+
+			lua_time["tempo"]        = metric.tempo ().quarter_notes_per_minute ();
+			lua_time["tempoEnd"]     = metric_end.tempo ().quarter_notes_per_minute ();
+			lua_time["musicTime"]    = DoubleableBeats (metric.tempo ().quarters_at_sample (start)).to_double ();
+			lua_time["musicTimeEnd"] = DoubleableBeats (metric_end.tempo ().quarters_at_sample (end)).to_double ();
+
+			lua_time["barPositionMusic"]   = bbt.bars * 4;
+			lua_time["timeSigNumerator"]   = metric.meter ().divisions_per_bar ();
+			lua_time["timeSigDenominator"] = metric.meter ().note_value ();
+
+			lua_time["TCframesPerSecond"]  = _session.timecode_frames_per_second ();
+			lua_time["TCdropFrames"]       = _session.timecode_drop_frames ();
+
+			if (_session.get_play_loop ()) {
+				Location* looploc = _session.locations ()->auto_loop_location ();
+				lua_time["looping"]        = true;
+				lua_time["loopStart"]      = looploc->start ().samples ();
+				lua_time["loopEnd"]        = looploc->end ().samples ();
+				lua_time["loopStartMusic"] = DoubleableBeats (tmap->quarters_at (looploc->start ())).to_double ();
+				lua_time["loopEndMusic"]   = DoubleableBeats (tmap->quarters_at (looploc->end ())).to_double ();
+			} else {
+				lua_time["looping"] = false;
+			}
+
+			luabridge::push (L, lua_time);
+			lua_setglobal (L, "time");
+		}
+
 		if (_lua_does_channelmapping) {
 			// run the DSP function
 			(*_lua_dsp)(&bufs, &in, &out, nframes, offset);
@@ -686,7 +748,6 @@ LuaProc::connect_and_run (BufferSet& bufs,
 			BufferSet& silent_bufs  = _session.get_silent_buffers (ChanCount (DataType::AUDIO, 1));
 			BufferSet& scratch_bufs = _session.get_scratch_buffers (ChanCount (DataType::AUDIO, 1));
 
-			lua_State* L = lua.getState ();
 			luabridge::LuaRef in_map (luabridge::newTable (L));
 			luabridge::LuaRef out_map (luabridge::newTable (L));
 
diff --git a/share/scripts/_time_info.lua b/share/scripts/_time_info.lua
new file mode 100644
index 0000000000..a882f9e9ae
--- /dev/null
+++ b/share/scripts/_time_info.lua
@@ -0,0 +1,44 @@
+ardour {
+	["type"]    = "dsp",
+	name        = "Time Info",
+	category    = "Utility",
+	author      = "Ardour Team",
+	license     = "MIT",
+	description = [[Example to use processing time info]]
+}
+
+function dsp_ioconfig ()
+	return { { midi_in = 1, midi_out = 1, audio_in = -1, audio_out = -1}, }
+end
+
+function dsp_options ()
+	return { time_info = true }
+end
+
+function dsp_run (_, _, n_samples)
+	assert (type(midiout) == "table")
+	assert (type(time) == "table")
+	assert (type(midiout) == "table")
+	local cnt = 1;
+
+	function tx_midi (time, data)
+		midiout[cnt] = {}
+		midiout[cnt]["time"] = time;
+		midiout[cnt]["data"] = data;
+		cnt = cnt + 1;
+	end
+
+	-- printing from rt-context is not thread-safe
+	print ("---")
+	for k,v in pairs (time) do
+		print (k, v);
+	end
+
+	-- pass-thru MIDI
+	for _,b in pairs (midiin) do
+		local t = b["time"] -- t = [ 1 .. n_samples ]
+		local d = b["data"] -- midi-event data
+		tx_midi (t, d)
+	end
+
+end