From 52ef66da4d785414e7ae5a60dd44a01727514169 Mon Sep 17 00:00:00 2001
From: Joerg Mueller <nexyon@gmail.com>
Date: Sun, 1 Aug 2010 22:33:50 +0000
Subject: Audaspace: * Created awesome filter classes :) * Made all filter
 effects use the filter classes instead of having the same implementation
 everywhere. * Added a Python API for LTI IIR filters. * Fixed a warning in
 creator.c that was introduced when adding game autoplay.

---
 intern/audaspace/FX/AUD_IIRFilterReader.cpp | 50 +++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 intern/audaspace/FX/AUD_IIRFilterReader.cpp

(limited to 'intern/audaspace/FX/AUD_IIRFilterReader.cpp')

diff --git a/intern/audaspace/FX/AUD_IIRFilterReader.cpp b/intern/audaspace/FX/AUD_IIRFilterReader.cpp
new file mode 100644
index 00000000000..120c9f8d0ae
--- /dev/null
+++ b/intern/audaspace/FX/AUD_IIRFilterReader.cpp
@@ -0,0 +1,50 @@
+/*
+ * $Id$
+ *
+ * ***** BEGIN LGPL LICENSE BLOCK *****
+ *
+ * Copyright 2009 Jörg Hermann Müller
+ *
+ * This file is part of AudaSpace.
+ *
+ * AudaSpace 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.
+ *
+ * AudaSpace 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 AudaSpace.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * ***** END LGPL LICENSE BLOCK *****
+ */
+
+#include "AUD_IIRFilterReader.h"
+
+AUD_IIRFilterReader::AUD_IIRFilterReader(AUD_IReader* reader,
+										 std::vector<float> b,
+										 std::vector<float> a) :
+	AUD_BaseIIRFilterReader(reader, b.size(), a.size()), m_a(a), m_b(b)
+{
+	for(int i = 1; i < m_a.size(); i++)
+		m_a[i] /= m_a[0];
+	for(int i = 0; i < m_b.size(); i++)
+		m_b[i] /= m_a[0];
+	m_a[0] = 1;
+}
+
+sample_t AUD_IIRFilterReader::filter()
+{
+	sample_t out = 0;
+
+	for(int i = 1; i < m_a.size(); i++)
+		out -= y(-i) * m_a[i];
+	for(int i = 0; i < m_b.size(); i++)
+		out += x(-i) * m_b[i];
+
+	return out;
+}
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