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Diffstat (limited to 'extern/audaspace/src/fx/Envelope.cpp')
-rw-r--r-- | extern/audaspace/src/fx/Envelope.cpp | 71 |
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 |