1 files changed, 71 insertions, 0 deletions
diff --git a/extern/audaspace/src/fx/Envelope.cpp b/extern/audaspace/src/fx/Envelope.cpp
new file mode 100644
index 00000000000..0637706c0a9
--- /dev/null
+++ b/extern/audaspace/src/fx/Envelope.cpp
@@ -0,0 +1,71 @@
+/*******************************************************************************
+ * Copyright 2009-2016 Jörg Müller
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ ******************************************************************************/
+
+#include "fx/Envelope.h"
+#include "fx/CallbackIIRFilterReader.h"
+
+#include <cmath>
+
+AUD_NAMESPACE_BEGIN
+
+struct EnvelopeParameters
+{
+	float attack;
+	float release;
+	float threshold;
+	float arthreshold;
+};
+
+sample_t Envelope::envelopeFilter(CallbackIIRFilterReader* reader, EnvelopeParameters* param)
+{
+	float in = std::fabs(reader->x(0));
+	float out = reader->y(-1);
+	if(in < param->threshold)
+		in = 0.0f;
+	return (in > out ? param->attack : param->release) * (out - in) + in;
+}
+
+void Envelope::endEnvelopeFilter(EnvelopeParameters* param)
+{
+	delete param;
+}
+
+Envelope::Envelope(std::shared_ptr<ISound> sound, float attack, float release, float threshold, float arthreshold) :
+		Effect(sound),
+		m_attack(attack),
+		m_release(release),
+		m_threshold(threshold),
+		m_arthreshold(arthreshold)
+{
+}
+
+std::shared_ptr<IReader> Envelope::createReader()
+{
+	std::shared_ptr<IReader> reader = getReader();
+
+	EnvelopeParameters* param = new EnvelopeParameters();
+	param->arthreshold = m_arthreshold;
+	param->attack = std::pow(m_arthreshold, 1.0f/(static_cast<float>(reader->getSpecs().rate) * m_attack));
+	param->release = std::pow(m_arthreshold, 1.0f/(static_cast<float>(reader->getSpecs().rate) * m_release));
+	param->threshold = m_threshold;
+
+	return std::shared_ptr<IReader>(new CallbackIIRFilterReader(reader, 1, 2,
+										   (doFilterIIR) envelopeFilter,
+										   (endFilterIIR) endEnvelopeFilter,
+										   param));
+}
+
+AUD_NAMESPACE_END