Implemented Gain processor to adjust signal volume without colouring

mwengine/CMakeLists.txt

@@ -117,6 +117,7 @@ set(MWENGINE_PROCESSORS ${CPP_SRC}/processors/bitcrusher.cpp
                         ${CPP_SRC}/processors/flanger.cpp
                         ${CPP_SRC}/processors/fm.cpp
                         ${CPP_SRC}/processors/formantfilter.cpp
+                        ${CPP_SRC}/processors/gain.cpp
                         ${CPP_SRC}/processors/glitcher.cpp
                         ${CPP_SRC}/processors/limiter.cpp
                         ${CPP_SRC}/processors/lowpassfilter.cpp

mwengine/src/main/cpp/mwengine.i

@@ -33,6 +33,7 @@ using namespace MWEngine;
 #include "processors/limiter.h"
 #include "processors/fm.h"
 #include "processors/formantfilter.h"
+#include "processors/gain.h"
 #include "processors/glitcher.h"
 #include "processors/lowpassfilter.h"
 #include "processors/lpfhpfilter.h"
@@ -115,6 +116,7 @@ typedef double SAMPLE_TYPE;
 %include "processors/lpfhpfilter.h"
 %include "processors/fm.h"
 %include "processors/formantfilter.h"
+%include "processors/gain.h"
 %include "processors/glitcher.h"
 %include "processors/phaser.h"
 %include "processors/pitchshifter.h"

mwengine/src/main/cpp/processors/gain.cpp

@@ -0,0 +1,91 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Igor Zinken - http://www.igorski.nl
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include "gain.h"
+#include <utilities/utils.h>
+#include <cmath>
+
+namespace MWEngine {
+
+/* constructor / destructor */
+
+Gain::Gain()
+{
+    setAmount( MAX_VOLUME );
+}
+
+Gain::Gain( float amount )
+{
+    setAmount( amount );
+}
+
+Gain::~Gain()
+{
+    // nowt...
+}
+
+/* public methods */
+
+void Gain::process( AudioBuffer* sampleBuffer, bool isMonoSource )
+{
+    // no gain specified ? do nothing
+    if ( _amount == MAX_VOLUME )
+        return;
+
+    int bufferSize = sampleBuffer->bufferSize;
+
+    for ( int i = 0, l = sampleBuffer->amountOfChannels; i < l; ++i )
+    {
+        SAMPLE_TYPE* channelBuffer = sampleBuffer->getBufferForChannel( i );
+
+        for ( int j = 0; j < bufferSize; ++j )
+        {
+            channelBuffer[ j ] = capSampleSafe( channelBuffer[ j ] * _amount );
+        }
+
+        // omit unnecessary cycles by copying the mono content
+        if ( isMonoSource )
+        {
+            sampleBuffer->applyMonoSource();
+            break;
+        }
+    }
+}
+
+bool Gain::isCacheable()
+{
+    return true;
+}
+
+/* getters / setters */
+
+float Gain::getAmount()
+{
+    return ( float ) _amount;
+}
+
+void Gain::setAmount( float value )
+{
+    _amount = std::max( MIN_GAIN, std::min( MAX_GAIN, ( SAMPLE_TYPE ) value ));
+}
+
+} // E.O namespace MWEngine

mwengine/src/main/cpp/processors/gain.h

@@ -0,0 +1,58 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Igor Zinken - https://www.igorski.nl
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef __MWENGINE__GAIN_H_INCLUDED__
+#define __MWENGINE__GAIN_H_INCLUDED__
+
+#include "baseprocessor.h"
+#include <global.h>
+
+namespace MWEngine {
+class Gain : public BaseProcessor
+{
+    public:
+        static constexpr SAMPLE_TYPE MIN_GAIN = SILENCE;
+        static constexpr SAMPLE_TYPE MAX_GAIN = 20;
+
+        Gain();
+        Gain( float amount );
+        ~Gain();
+
+        std::string getType() {
+            return std::string( "Gain" );
+        }
+
+        float getAmount();
+        void setAmount( float value );
+
+#ifndef SWIG
+        // internal to the engine
+        void process( AudioBuffer* sampleBuffer, bool isMonoSource );
+        bool isCacheable();
+#endif
+
+    private:
+        SAMPLE_TYPE _amount;
+};
+} // E.O namespace MWEngine
+
+#endif

mwengine/src/main/cpp/tests/main.cpp

@@ -60,6 +60,7 @@ using namespace MWEngine;
 #include "processors/flanger_test.cpp"
 #include "processors/fm_test.cpp"
 #include "processors/formantfilter_test.cpp"
+#include "processors/gain_test.cpp"
 #include "processors/glitcher_test.cpp"
 #include "processors/limiter_test.cpp"
 #include "processors/lowpassfilter_test.cpp"

mwengine/src/main/cpp/tests/processors/gain_test.cpp

@@ -0,0 +1,51 @@
+#include <processors/gain.h>
+#include <global.h>
+
+TEST( Gain, Constructors )
+{
+    auto processor = new Gain();
+
+    EXPECT_EQ( MAX_VOLUME, processor->getAmount() )
+        << "expected default gain to equal the maximum volume";
+
+    delete processor;
+
+    processor = new Gain( 0.5f );
+
+    EXPECT_EQ( 0.5f, processor->getAmount() )
+        << "expected default gain to equal the amount provided to the constructor";
+
+    delete processor;
+}
+
+TEST( Gain, getType )
+{
+    auto processor = new Gain();
+
+    std::string expectedType( "Gain" );
+    ASSERT_TRUE( 0 == expectedType.compare( processor->getType() ));
+
+    delete processor;
+}
+
+TEST( Gain, setAmount )
+{
+    auto processor = new Gain();
+
+    processor->setAmount( 2.f );
+
+    EXPECT_EQ( 2.f, processor->getAmount() )
+        << "expected gain amount to equal the value passed to the setter";
+
+    processor->setAmount( Gain::MIN_GAIN - 1 );
+
+    EXPECT_EQ( Gain::MIN_GAIN, processor->getAmount() )
+        << "expected out of range gain amount to have been capped to the minimum supported value";
+
+    processor->setAmount( Gain::MAX_GAIN + 1 );
+
+    EXPECT_EQ( Gain::MAX_GAIN, processor->getAmount() )
+        << "expected out of range gain amount to have been capped to the maximum supported value";
+
+    delete processor;
+}