From 9581cb26e444229301d5fdafadd14ca5c0a83a18 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sat, 3 Jun 2017 13:18:31 +0200
Subject: Add infrastructure for evaluating VCA automation curves

---
 libs/ardour/ardour/slavable_automation_control.h |  8 ++++
 libs/ardour/slavable_automation_control.cc       | 55 ++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/libs/ardour/ardour/slavable_automation_control.h b/libs/ardour/ardour/slavable_automation_control.h
index 6467dcd6de..f89d29c0d2 100644
--- a/libs/ardour/ardour/slavable_automation_control.h
+++ b/libs/ardour/ardour/slavable_automation_control.h
@@ -50,6 +50,14 @@ class LIBARDOUR_API SlavableAutomationControl : public AutomationControl
 		return get_masters_value_locked ();
 	}
 
+	bool get_masters_curve (framepos_t s, framepos_t e, float* v, framecnt_t l) const {
+		Glib::Threads::RWLock::ReaderLock lm (master_lock);
+		return get_masters_curve_locked (s, e, v, l);
+	}
+	virtual bool get_masters_curve_locked (framepos_t, framepos_t, float*, framecnt_t) const;
+
+	bool masters_curve_multiply (framepos_t, framepos_t, float*, framecnt_t) const;
+
 	/* for toggled/boolean controls, returns a count of the number of
 	   masters currently enabled. For other controls, returns zero.
 	*/
diff --git a/libs/ardour/slavable_automation_control.cc b/libs/ardour/slavable_automation_control.cc
index 6df2dd2720..40f4cb486f 100644
--- a/libs/ardour/slavable_automation_control.cc
+++ b/libs/ardour/slavable_automation_control.cc
@@ -24,6 +24,8 @@
 #include "pbd/types_convert.h"
 #include "pbd/i18n.h"
 
+#include "evoral/Curve.hpp"
+
 #include "ardour/audioengine.h"
 #include "ardour/slavable_automation_control.h"
 #include "ardour/session.h"
@@ -110,6 +112,59 @@ SlavableAutomationControl::get_value() const
 	}
 }
 
+bool
+SlavableAutomationControl::get_masters_curve_locked (framepos_t, framepos_t, float*, framecnt_t) const
+{
+	/* Every AutomationControl needs to implement this as-needed.
+	 *
+	 * This class also provides some convenient methods which
+	 * could be used as defaults here (depending on  AutomationType)
+	 * e.g. masters_curve_multiply()
+	 */
+	return false;
+}
+
+bool
+SlavableAutomationControl::masters_curve_multiply (framepos_t start, framepos_t end, float* vec, framecnt_t veclen) const
+{
+	bool rv = list()->curve().rt_safe_get_vector (start, end, vec, veclen);
+	if (_masters.empty()) {
+		return rv;
+	}
+	gain_t* scratch = _session.scratch_automation_buffer ();
+	for (Masters::const_iterator mr = _masters.begin(); mr != _masters.end(); ++mr) {
+		boost::shared_ptr<AutomationControl> ac (mr->second.master());
+		bool got_curve;
+
+		boost::shared_ptr<SlavableAutomationControl> sc
+			= boost::dynamic_pointer_cast<SlavableAutomationControl>(ac);
+		if (sc) {
+			got_curve = sc->get_masters_curve_locked (start, end, scratch, veclen);
+		} else {
+			got_curve = ac->list()->curve().rt_safe_get_vector (start, end, scratch, veclen);
+		}
+		if (got_curve) {
+			// TODO use SSE/AVX methods, e.g. ARDOUR::apply_gain_to_buffer, mix_buffers_no_gain
+			// which works as long as automation _types_ gain_t == ARDOUR::Sample type == float
+			if (!rv) {
+				// TODO optimize this, in case rv is false, direcly use "vec" above.
+				rv = true;
+				memcpy (vec, scratch, sizeof (float) * veclen);
+			} else {
+				for (framecnt_t i = 0; i < veclen; ++i) {
+					vec[i] *= scratch[i];
+				}
+			}
+		} else if (rv) {
+			const float v = get_masters_value ();
+			for (framecnt_t i = 0; i < veclen; ++i) {
+				vec[i] *= v;
+			}
+		}
+	}
+	return rv;
+}
+
 void
 SlavableAutomationControl::actually_set_value (double value, PBD::Controllable::GroupControlDisposition gcd)
 {
-- 
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