From 65ecc1b40e91d9b352ebf1bf3dc0cf22821085c7 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sat, 15 Aug 2020 01:52:38 +0200
Subject: [PATCH] Do not interpolate away explicit MIDI automation points #8362

---
 libs/evoral/ControlList.cc       | 31 +++++++++++++++++++++++++++----
 libs/evoral/Sequence.cc          |  2 +-
 libs/evoral/evoral/ControlList.h |  2 +-
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/libs/evoral/ControlList.cc b/libs/evoral/ControlList.cc
index cde1718e23..5b8b6349f4 100644
--- a/libs/evoral/ControlList.cc
+++ b/libs/evoral/ControlList.cc
@@ -1587,7 +1587,7 @@ ControlList::rt_safe_earliest_event_discrete_unlocked (double start, double& x,
  * \return true if event is found (and \a x and \a y are valid).
  */
 bool
-ControlList::rt_safe_earliest_event_linear_unlocked (double start, double& x, double& y, bool inclusive) const
+ControlList::rt_safe_earliest_event_linear_unlocked (double start, double& x, double& y, bool inclusive, double min_x_delta) const
 {
 	// cout << "earliest_event(start: " << start << ", x: " << x << ", y: " << y << ", inclusive: " << inclusive <<  ")" << endl;
 
@@ -1595,9 +1595,30 @@ ControlList::rt_safe_earliest_event_linear_unlocked (double start, double& x, do
 	if (_events.empty()) { // 0 events
 		return false;
 	} else if (_events.end() == ++length_check_iter) { // 1 event
-		return rt_safe_earliest_event_discrete_unlocked (start, x, y, inclusive);
+		return rt_safe_earliest_event_discrete_unlocked (start + min_x_delta, x, y, inclusive);
 	}
 
+
+	if (min_x_delta > 0) {
+		/* if there is an event between [start and start + min_x_delta], use it,
+		 * otherwise interpolate at start + min_x_delta
+		 */
+		build_search_cache_if_necessary (start);
+		const ControlEvent* first = *_search_cache.first;
+		if (_search_cache.first != _events.end()) {
+			if (((first->when > start) || (inclusive && first->when == start)) && first->when < start + min_x_delta) {
+				x = first->when;
+				y = first->value;
+				/* Move left of cache to this point
+				 * (Optimize for immediate call this cycle within range) */
+				_search_cache.left = x;
+				return true;
+			}
+		}
+	}
+
+	start += min_x_delta;
+
 	// Hack to avoid infinitely repeating the same event
 	build_search_cache_if_necessary (start);
 
@@ -1671,9 +1692,11 @@ ControlList::rt_safe_earliest_event_linear_unlocked (double start, double& x, do
 			x = first->when + (y - first->value) / (double)slope;
 		}
 
-		/*cerr << first->value << " @ " << first->when << " ... "
+#if 0
+		cerr << first->value << " @ " << first->when << " ... "
 		  << next->value << " @ " << next->when
-		  << " = " << y << " @ " << x << endl;*/
+		  << " = " << y << " @ " << x << endl;
+#endif
 
 		assert(    (y >= first->value && y <= next->value)
 		           || (y <= first->value && y >= next->value) );
diff --git a/libs/evoral/Sequence.cc b/libs/evoral/Sequence.cc
index 0f501732d0..2ba0b0bb24 100644
--- a/libs/evoral/Sequence.cc
+++ b/libs/evoral/Sequence.cc
@@ -370,7 +370,7 @@ Sequence<Time>::const_iterator::operator++()
 				_control_iter->x, x, y, false);
 		} else {
 			ret = _control_iter->list->rt_safe_earliest_event_linear_unlocked (
-				_control_iter->x + time_between_interpolated_controller_outputs, x, y, false);
+				_control_iter->x, x, y, false, time_between_interpolated_controller_outputs);
 		}
 		assert(!ret || x > _control_iter->x);
 		if (ret) {
diff --git a/libs/evoral/evoral/ControlList.h b/libs/evoral/evoral/ControlList.h
index 1c9c2192d0..c33e47c650 100644
--- a/libs/evoral/evoral/ControlList.h
+++ b/libs/evoral/evoral/ControlList.h
@@ -298,8 +298,8 @@ public:
 	 */
 	double unlocked_eval (double x) const;
 
-	bool rt_safe_earliest_event_linear_unlocked (double start, double& x, double& y, bool inclusive) const;
 	bool rt_safe_earliest_event_discrete_unlocked (double start, double& x, double& y, bool inclusive) const;
+	bool rt_safe_earliest_event_linear_unlocked (double start, double& x, double& y, bool inclusive, double min_d_delta = 0) const;
 
 	void create_curve();
 	void destroy_curve();