Tempo based time in Machina (and related utilities added to Raul).

git-svn-id: http://svn.drobilla.net/lad/raul@324 a436a847-0d15-0410-975c-d299462d15a1

1 files changed, 160 insertions, 0 deletions

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+/* This file is part of Raul.
+ * Copyright (C) 2007 Dave Robillard <http://drobilla.net>
+ * 
+ * Raul is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 2 of the License, or (at your option) any later
+ * version.
+ * 
+ * Raul is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef RAUL_TIMESLICE_H
+#define RAUL_TIMESLICE_H
+
+#include <cassert>
+#include <boost/utility.hpp>
+
+namespace Raul {
+
+
+typedef uint32_t TickTime;  ///< absolute time in ticks
+typedef uint32_t TickCount; ///< offset in ticks
+typedef double   BeatTime;
+typedef double   BeatCount;
+typedef double   Seconds;
+
+
+/** A duration of time, with conversion between tick time and beat time.
+ *
+ * This is a slice along a single timeline (ie t=0 in ticks and t=0 in beats
+ * are equal).  Relation to an external time base (e.g. Jack frame time) is
+ * represented by frame_offset (the idea is that this holds all the information
+ * necessary for passing to run() methods so they know the current state of
+ * things WRT time).
+ *
+ * This class handles conversion between two units of time: musical
+ * (beat) time, and real (tick) time.  Real time is discrete, the smallest
+ * unit of time is the 'tick' (usually audio frames or MIDI ticks).  Beat time
+ * is stored as a double (to be independent of any rates or timer precision).
+ *
+ * This caches as many values as possible to make calls less expensive, pass it
+ * around by reference, not value.
+ *
+ * \ingroup raul
+ */
+class TimeSlice : public boost::noncopyable {
+public:
+	TimeSlice(double tick_rate, double bpm)
+		: _tick_rate(tick_rate)
+		, _beat_rate(60.0/bpm)
+		, _start_ticks(0)
+		, _length_ticks(0)
+		, _start_beats(0)
+		, _length_beats(0)
+		, _offset_ticks(0)
+	{}
+
+
+	/** Set the start and length of the slice.
+	 *
+	 * Note that external offset is not affected by this, don't forget to reset
+	 * the offset each cycle!
+	 */
+	void set_window(TickTime start, TickCount length) {
+		_start_ticks = start;
+		_length_ticks = length;
+		update_beat_time();
+	}
+
+	void set_start(TickTime time) { _start_ticks = time; update_beat_time(); }
+
+	void set_length(TickCount length) { _length_ticks = length; update_beat_time(); }
+
+	bool contains(TickTime time) {
+		return (time >= start_ticks() && time < start_ticks() + length_ticks());
+	}
+
+	void set_tick_rate(double tick_rate) {
+		_tick_rate = tick_rate;
+		update_beat_time();
+	}
+
+	void set_bpm(double bpm) {
+		_beat_rate = 60.0/bpm;
+		update_beat_time();
+	}
+	
+	inline Seconds beats_to_seconds(BeatTime beats) const {
+		return (beats * _beat_rate);
+	}
+
+	inline TickTime beats_to_ticks(BeatTime beats) const {
+		return static_cast<TickTime>(beats_to_seconds(beats) / _tick_rate); 
+	}
+		
+	inline Seconds ticks_to_seconds(TickTime ticks) const {
+		return (ticks * _tick_rate);
+	}
+
+	inline BeatTime ticks_to_beats(TickTime ticks) const {
+		return ticks_to_seconds(ticks) / _beat_rate;
+	}
+	
+	/** Start of current sub-cycle in ticks */
+	inline TickTime start_ticks() const { return _start_ticks; }
+
+	/** Length of current sub-cycle in ticks */
+	inline TickCount length_ticks() const { return _length_ticks; }
+
+	/** Start of current sub-cycle in beats */
+	inline BeatTime start_beats() const { return _start_beats; }
+
+	/** Length of current sub-cycle in beats */
+	inline BeatCount length_beats() const { return _length_beats; }
+
+
+	// Real-time conversion
+/*
+	TickCount ticks_to_offset(TickTime time) {
+		assert(time >= _start_ticks);
+		TickCount ret = time - _start_ticks + _offset_ticks;
+		assert(ret < _offset_ticks + _length_ticks);
+		return ret;
+	}
+*/
+	/** Set the offset between real-time and timeslice-time. */
+	inline void set_offset(TickCount offset) { _offset_ticks = offset; }
+	/** Offset relative to external (e.g Jack) time */
+	inline TickCount offset_ticks() const { return _offset_ticks; }
+
+private:
+
+	inline void update_beat_time() {
+		_start_beats  = ticks_to_beats(_start_ticks);
+		_length_beats = ticks_to_beats(_length_ticks);
+	}
+
+	// Rate/Tempo
+	double _tick_rate; ///< Tick rate in Hz (e.g. sample rate)
+	double _beat_rate; ///< Beat rate in Hz
+
+	// Current time
+	TickTime  _start_ticks;  ///< Current window start in ticks
+	TickCount _length_ticks; ///< Current window length in ticks
+	BeatTime  _start_beats;  ///< Current window start in beats
+	BeatCount _length_beats; ///< Current window length in beats
+	
+	TickCount _offset_ticks; ///< Offset to global time (ie Jack sub-cycle offset)
+};
+
+
+} // namespace Raul
+
+#endif // RAUL_TIMESLICE_H