Skeleton for NI Maschine2 Surface

[ardour.git] / libs / surfaces / maschine2 / m2_encoder.h

diff --git a/libs/surfaces/maschine2/m2_encoder.h b/libs/surfaces/maschine2/m2_encoder.h
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+++ b/libs/surfaces/maschine2/m2_encoder.h
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+/*
+ * Copyright (C) 2016 Robin Gareus <robin@gareus.org>
+ *
+ * This program 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, or (at your option)
+ * any later version.
+ *
+ * This program 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 more 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 Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef _ardour_surfaces_m2encoder_h_
+#define _ardour_surfaces_m2encoder_h_
+
+#include <stdint.h>
+#include "pbd/signals.h"
+
+namespace ArdourSurface {
+
+class M2EncoderInterface
+{
+       public:
+               M2EncoderInterface () {}
+               virtual ~M2EncoderInterface () {}
+
+               /* user API */
+               PBD::Signal1<void, int> changed;
+               virtual float value () const { return 0.f; }
+               virtual float range () const { return 0.f; }
+
+               /* internal API - called from device thread */
+               virtual bool set_value (unsigned int v) { return false; }
+};
+
+class M2Encoder : public M2EncoderInterface
+{
+       public:
+               M2Encoder (unsigned int upper = 1000)
+                       : M2EncoderInterface ()
+                       , _upper (upper /* limit, exclusive. eg [0..15]: 16 */)
+                       , _value (0)
+                       , _initialized (false)
+               {
+                       assert (_upper > 7);
+                       _wrapcnt = std::max (3U, upper / 6);
+               }
+
+               float value () const { return _value / (_upper - 1.f); }
+               float range () const { return (_upper - 1.f); }
+
+               bool set_value (unsigned int v) {
+                       if (!_initialized) {
+                               _initialized = true;
+                               _value = v;
+                               return false;
+                       }
+
+                       if (v == _value) {
+                               return false;
+                       }
+
+                       int delta;
+                       if (v < _wrapcnt && _value > _upper - _wrapcnt) {
+                               // wrap around max -> min
+                               delta = v + _upper - _value;
+                       }
+                       else if (_value < _wrapcnt && v > _upper - _wrapcnt) {
+                               // wrap around min -> max
+                               delta = v - _upper - _value;
+                       }
+                       else {
+                               delta = v - _value;
+                       }
+
+                       _value = v;
+                       changed (delta);
+                       return true;
+               }
+
+       protected:
+               unsigned int _upper;
+               unsigned int _value;
+               unsigned int _wrapcnt;
+               bool _initialized;
+};
+
+} /* namespace */
+#endif /* _ardour_surfaces_m2encoder_h_ */
+
+