From cf790d239d4b5dfa772d5d1fdb112b8640a4a81a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Nusser?= <andre.nusser@googlemail.com>
Date: Sat, 2 May 2020 12:21:16 +0200
Subject: Add powermap functionality to the engine for mapping input velocities
 through a Monotone cubic splines due to Steffen.

---
 src/powermap.h | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 src/powermap.h

(limited to 'src/powermap.h')

diff --git a/src/powermap.h b/src/powermap.h
new file mode 100644
index 0000000..3a406cc
--- /dev/null
+++ b/src/powermap.h
@@ -0,0 +1,76 @@
+/* -*- Mode: c++ -*- */
+/***************************************************************************
+ *            powermap.h
+ *
+ *  Fri Apr 17 23:06:12 CEST 2020
+ *  Copyright 2020 André Nusser
+ *  andre.nusser@googlemail.com
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo 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 Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#pragma once
+
+#include <array>
+#include <vector>
+
+class Powermap
+{
+public:
+	using Power = float;
+	using Powers = std::vector<Power>;
+	struct PowerPair
+	{
+		Power in;
+		Power out;
+
+		bool operator!=(const PowerPair& other)
+		{
+			return in != other.in || out != other.out;
+		}
+	};
+
+	Powermap();
+
+	Power map(Power in);
+	void reset();
+
+	void setFixed0(PowerPair new_value);
+	void setFixed1(PowerPair new_value);
+	void setFixed2(PowerPair new_value);
+	void setShelf(bool enable);
+
+	PowerPair getFixed0() const;
+	PowerPair getFixed1() const;
+	PowerPair getFixed2() const;
+
+private:
+	// input parameters (state of this class)
+	std::array<PowerPair, 3> fixed;
+	bool shelf;
+
+	// spline parameters (deterministically computed from the input parameters)
+	bool spline_needs_update;
+	std::array<float, 5> m;
+	const Power eps = 1e-4;
+
+	void updateSpline();
+	std::vector<float> calcSlopes(const Powers& X, const Powers& P);
+
+	Power clamp(Power in, Power min, Power max) const;
+};
-- 
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