some reworks

src/main/kotlin/music/Frac.kt

@@ -0,0 +1,8 @@
+package music
+
+class Frac(val upper: Int, val lower: Int) {
+    val numerator = upper;
+    val denominator = lower;
+
+    fun value(): Double = upper / lower.toDouble();
+}

src/main/kotlin/music/Main.kt

@@ -28,7 +28,7 @@ fun main() {
 
     //val gen = ToneGenerator(.2f, -24, WaveformTransformation.SAWTOOTH)
 
-    val bpm = 60;
+    val bpm = 90;
     val volume = 0.1f;
     val tetrisSound = { volume: Float, tone: Int -> EasedToneGenerator(volume, tone, WaveformTransformation.SQUARE) }
 
@@ -116,10 +116,6 @@ fun main() {
             .pause(0.25) // 7
             .add("A", 0.5, offset = -1)
             .applyTo(bar2)
-    // D F A G F E
-    // C E D C B
-    // B C D E C A A
-
 
     val echo = EchoFilter(SAMPLES / 12, .9f)
     val limiter = Limiter(.9f);

src/main/kotlin/music/Samples.kt

@@ -3,37 +3,37 @@ package music
 import music.Params.SAMPLES
 import kotlin.math.absoluteValue
 
-typealias Samples = Array<Float>
+typealias TimeSamples = Array<Float>
 
-fun Samples(len: Float, start: Float = 0f): Samples =
-        Samples((len * SAMPLES).toInt()) { i -> start + (i / SAMPLES.toFloat())}
+fun Samples(len: Float, start: Float = 0f): TimeSamples =
+        TimeSamples((len * SAMPLES).toInt()) { i -> start + (i / SAMPLES.toFloat())}
 
-fun Samples(len: Int, start: Float = 0f): Samples = Samples(len.toFloat(), start)
+fun Samples(len: Int, start: Float = 0f): TimeSamples = Samples(len.toFloat(), start)
 
-fun Samples.map(mapper: (Float) -> (Float)): Samples =
+fun TimeSamples.map(mapper: (Float) -> (Float)): TimeSamples =
     Array(size) { mapper(this[it]) }
 
-fun Samples.ceil(): Samples =
+fun TimeSamples.ceil(): TimeSamples =
     map { kotlin.math.ceil(it) }
 
-fun Samples.sin(): Samples =
+fun TimeSamples.sin(): TimeSamples =
     map { kotlin.math.sin(it) }
 
-fun Samples.mod(num: Int): Samples =
+fun TimeSamples.mod(num: Int): TimeSamples =
         map { it % num }
 
-fun Samples.abs(): Samples =
+fun TimeSamples.abs(): TimeSamples =
         map { it.absoluteValue }
 
-operator fun Samples.times(scalar: Float): Samples =
+operator fun TimeSamples.times(scalar: Float): TimeSamples =
     if (scalar == 1f) this else map { it * scalar }
 
-operator fun Samples.plus(value: Float): Samples =
+operator fun TimeSamples.plus(value: Float): TimeSamples =
     map { it + value }
 
-operator fun Samples.minus(value: Float): Samples =
+operator fun TimeSamples.minus(value: Float): TimeSamples =
     map { it - value }
 
-operator fun Samples.div(value: Float): Samples =
+operator fun TimeSamples.div(value: Float): TimeSamples =
     map { it / value }
 

src/main/kotlin/music/Signal.kt

@@ -6,53 +6,53 @@ import music.Params.PI
 /**
  * A Signal is string of Integer values which describe a curve, they go from - MAX_VAL to MAX_VAL
  */
-typealias Signal = Array<Int>
+typealias SoundSamples = Array<Int>
 
-fun Signal.toBytes(): ByteArray =
+fun SoundSamples.toBytes(): ByteArray =
     Array(size * 2) { i -> (this[i/2] shr ((i % 2) * 8)).toByte() }.toByteArray()
 
-fun Signal(samples: Samples): Signal =
-        Signal(samples.size) {i -> (samples[i] * MAX_VAL).toInt() }
+fun SoundSamples(timeSamples: TimeSamples): SoundSamples =
+        SoundSamples(timeSamples.size) { i -> (timeSamples[i] * MAX_VAL).toInt() }
 
 enum class WaveformTransformation {
     SINE {
-        override fun apply(samples: Samples, volume: Float): Signal
-                = Signal(((samples * (2f * PI)).sin()) * volume)
+        override fun apply(timeSamples: TimeSamples, volume: Float): SoundSamples
+                = SoundSamples(((timeSamples * (2f * PI)).sin()) * volume)
     },
     SQUARE {
-        override fun apply(samples: Samples, volume: Float): Signal
-                = Signal(samples.times(2f).ceil().mod(2).times(2f).minus(1f) * (volume))
+        override fun apply(timeSamples: TimeSamples, volume: Float): SoundSamples
+                = SoundSamples(timeSamples.times(2f).ceil().mod(2).times(2f).minus(1f) * (volume))
     },
     SAWTOOTH {
-        override fun apply(samples: Samples, volume: Float): Signal
-                = Signal(((samples * 2f).mod(2) - 1f) * volume)
+        override fun apply(timeSamples: TimeSamples, volume: Float): SoundSamples
+                = SoundSamples(((timeSamples * 2f).mod(2) - 1f) * volume)
     },
     TRIANGLE {
-        override fun apply(samples: Samples, volume: Float): Signal
-                = Signal(samples.times(4f).mod(4).minus(2f).abs().minus(1f) * (volume))
+        override fun apply(timeSamples: TimeSamples, volume: Float): SoundSamples
+                = SoundSamples(timeSamples.times(4f).mod(4).minus(2f).abs().minus(1f) * (volume))
     };
 
-    open fun apply(samples: Samples, volume: Float): Signal = Signal(samples * volume)
+    open fun apply(timeSamples: TimeSamples, volume: Float): SoundSamples = SoundSamples(timeSamples * volume)
 }
 
-fun Signal.map(mapper: (Int) -> (Int)): Signal =
+fun SoundSamples.map(mapper: (Int) -> (Int)): SoundSamples =
         Array(size) { mapper(this[it]) }
 
-operator fun Signal.times(scalar: Float): Signal =
+operator fun SoundSamples.times(scalar: Float): SoundSamples =
         if (scalar == 1f) this else map { (it * scalar).toInt() }
 
-operator fun Signal.plus(value: Int): Signal =
+operator fun SoundSamples.plus(value: Int): SoundSamples =
         map { it + value }
 
-operator fun Signal.minus(value: Int): Signal =
+operator fun SoundSamples.minus(value: Int): SoundSamples =
         map { it - value }
 
-operator fun Signal.div(value: Float): Signal =
+operator fun SoundSamples.div(value: Float): SoundSamples =
         map { (it / value).toInt() }
 
 
-fun Signal.join(start: Int, signal: Signal): Signal
+fun SoundSamples.join(start: Int, soundSamples: SoundSamples): SoundSamples
     = (this.sliceArray(0 until start)
-        + signal.withIndex().map { i -> this.elementAtOrElse(i.index + start) {0} + i.value }
-        + this.sliceArray(start + signal.size until this.size))
+        + soundSamples.withIndex().map { i -> this.elementAtOrElse(i.index + start) {0} + i.value }
+        + this.sliceArray(start + soundSamples.size until this.size))
 

src/main/kotlin/music/Track.kt

@@ -1,10 +1,7 @@
 package music
 
 import music.Params.SAMPLES
-import music.filter.EaseFilter
-import music.filter.FilterQueue
 import music.generators.Generator
-import java.util.logging.Filter
 
 
 class Track {
@@ -19,8 +16,8 @@ class Bar(val beats: Int, val bpm: Int) {
     val bps = bpm / 60f
     val tones = mutableSetOf<Beat>()
 
-    fun getSignal():Signal {
-        var base = Signal((SAMPLES * beats / bps).toInt()) {0}
+    fun getSignal():SoundSamples {
+        var base = SoundSamples((SAMPLES * beats / bps).toInt()) {0}
         for (tone in tones) {
             base = base.join((SAMPLES * tone.start / bps).toInt(), tone.getSignal(bps))
         }
@@ -30,6 +27,6 @@ class Bar(val beats: Int, val bpm: Int) {
 }
 
 class Beat(private val generator: Generator, private val duration: Float, val start: Float) {
-    fun getSignal(bps: Float): Signal =
+    fun getSignal(bps: Float): SoundSamples =
         generator.get(Samples(duration / bps, start / bps))
 }

src/main/kotlin/music/filter/Compressor.kt

@@ -1,10 +1,29 @@
 package music.filter
 
-import music.Signal
+import music.Frac
+import music.SoundSamples
+import music.map
+import kotlin.math.log10
 
-class Compressor(val threshold: Int, val ratio: Float, val outputGain: Float):Filter {
+/**
+ * @param threshold the threshold when the compressor starts in decibel
+ * @param ratio how much to compress when crossing the threshold. A ration of 6/1 means 1 decibel output for each 6 decibel over the threshold
+ * @param outputGain how much the signal should be amplified after compression
+ */
+class Compressor(private val threshold: Int, val ratio: Frac, val outputGain: Float):Filter() {
+    override fun stream(soundSamples: SoundSamples): SoundSamples {
+        return soundSamples.map(this::apply)
+    }
+
+    private fun apply(sample: Int): Int {
+        val db = signalToDB(sample)
+
+        if (db > threshold) {
+            val surplus = db - threshold;
+            val reduction = surplus - (surplus / ratio.value())
+            return dBToSignal(db - reduction + outputGain)
+        }
 
-    override fun stream(signal: Signal): Signal {
-        return signal;
+        return dBToSignal(db + outputGain);
     }
 }

src/main/kotlin/music/filter/EchoFilter.kt

@@ -1,9 +1,7 @@
 package music.filter
 
-import music.Signal
+import music.SoundSamples
 import music.map
-import music.div
-import music.times
 import java.util.*
 import kotlin.math.absoluteValue
 import kotlin.math.pow
@@ -12,8 +10,8 @@ import kotlin.math.sign
 class EchoFilter(delay: Int, private val volume: Float = 0.5f): Filter {
     private var cache: Queue<Int> = LinkedList(List(delay) {0})
 
-    override fun stream(signal: Signal): Signal =
-        signal.map(this::apply)
+    override fun stream(soundSamples: SoundSamples): SoundSamples =
+        soundSamples.map(this::apply)
 
     private fun apply(value: Int): Int {
         val effect = value + cache.remove()

src/main/kotlin/music/filter/Filter.kt

@@ -1,53 +1,40 @@
 package music.filter
 
-import music.Signal
-
-interface Filter {
-    fun stream(signal: Signal): Signal
-}
-
-
+import music.SoundSamples
+import kotlin.math.log10
+import kotlin.math.pow
 
+abstract class Filter {
+    abstract fun stream(soundSamples: SoundSamples): SoundSamples
 
+    protected fun signalToDB(signal: Int): Double =
+            20 * log10(signal.toDouble())
 
+    protected fun dBToSignal(db: Double): Int =
+            10.0.pow(db / 20).toInt()
+}
 
-enum class EaseFilter(val duration: Int = 32): Filter {
-    IN {
-        override fun stream (signal: Signal): Signal {
-            val len = kotlin.math.min(duration, signal.size)
-            val start = signal.slice(0 until len)
-            val end = signal.slice(len until signal.size)
-
-            return (start.withIndex().map { i -> (i.value * (i.index / len.toFloat())).toInt() } + end).toTypedArray();
-        }
-    },
-
-    OUT {
-        override fun stream(signal: Signal): Signal {
-            val len = kotlin.math.min(duration, signal.size)
-            val sep = signal.size - len - 1;
-            val start = signal.slice(0 until sep)
-            val end = signal.slice(sep until signal.size)
+object DefaultEases {
+    val IN = EaseFilter(32, 0)
+    val OUT = EaseFilter(0, 32)
+    val INOUT = EaseFilter(32, 32)
+}
 
-            return (start + end.withIndex().map { i -> (i.value * ((len - i.index) / len.toFloat())).toInt() }).toTypedArray();
-        }
-    },
+class EaseFilter(val inDuration: Int, val outDuration: Int): Filter() {
 
-    INOUT {
-        override fun stream(signal: Signal): Signal {
-            val len = kotlin.math.min(duration, signal.size / 2)
-            val sep = signal.size - len - 1;
-            val start = signal.slice(0 until len)
-            val mid = signal.slice(len until sep)
-            val end = signal.slice(sep until signal.size)
+    override fun stream(soundSamples: SoundSamples): SoundSamples {
+        val inlen = kotlin.math.min(inDuration, soundSamples.size - outDuration)
+        val outlen = kotlin.math.min(outDuration, soundSamples.size - inlen)
 
-            return (start.withIndex().map { i -> (i.value * (i.index / len.toFloat())).toInt() }
-                    + mid
-                    + end.withIndex().map { i -> (i.value * ((len - i.index) / len.toFloat())).toInt() }
-                    ).toTypedArray();
-        }
-    };
+        val sep = soundSamples.size - outlen - 1;
+        val start = soundSamples.slice(0 until inlen)
+        val mid = soundSamples.slice(inlen until sep)
+        val end = soundSamples.slice(sep until soundSamples.size)
 
-    override fun stream(signal: Signal): Signal = signal
+        return (start.withIndex().map { i -> (i.value * (i.index / inlen.toFloat())).toInt() }
+                + mid
+                + end.withIndex().map { i -> (i.value * ((outlen - i.index) / outlen.toFloat())).toInt() }
+                ).toTypedArray();
+    }
 }
 

src/main/kotlin/music/filter/FilterQueue.kt

@@ -1,8 +1,8 @@
 package music.filter
 
-import music.Signal
+import music.SoundSamples
 
 class FilterQueue(private vararg val filters: Filter): Filter {
-    override fun stream(signal: Signal): Signal =
-            filters.fold(signal, {acc, filter -> filter.stream(acc)})
+    override fun stream(soundSamples: SoundSamples): SoundSamples =
+            filters.fold(soundSamples, { acc, filter -> filter.stream(acc)})
 }

src/main/kotlin/music/filter/Limiter.kt

@@ -1,7 +1,7 @@
 package music.filter
 
 import music.Params.MAX_VAL
-import music.Signal
+import music.SoundSamples
 import music.map
 import kotlin.math.max
 import kotlin.math.min
@@ -9,6 +9,6 @@ import kotlin.math.min
 class Limiter(val threshold: Float): Filter {
     val maxVal = (MAX_VAL * threshold).toInt()
 
-    override fun stream(signal: Signal): Signal =
-            signal.map { max(min(it, maxVal), - maxVal) }
+    override fun stream(soundSamples: SoundSamples): SoundSamples =
+            soundSamples.map { max(min(it, maxVal), - maxVal) }
 }

src/main/kotlin/music/generators/Drum.kt

@@ -13,10 +13,10 @@ class Drum(volume: Float, tone: Int = -36): Generator{
     val gen1 = EasedToneGenerator(volume, tone, WaveformTransformation.SINE)
     val gen2 = EasedToneGenerator(volume / 2, tone + 12, WaveformTransformation.SINE)
 
-    override fun get(samples: Samples): Signal {
-        val kick1 = gen1.get(samples.sliceArray(0 until kickLen))
-        val kick2 = gen2.get(samples.sliceArray(0 until (kickLen / 2)))
+    override fun get(timeSamples: TimeSamples): SoundSamples {
+        val kick1 = gen1.get(timeSamples.sliceArray(0 until kickLen))
+        val kick2 = gen2.get(timeSamples.sliceArray(0 until (kickLen / 2)))
 
-        return filter.stream(kick1.join(0, kick2) + Signal(max(samples.size - kickLen, 0)) {0}) / 1.5f;
+        return filter.stream(kick1.join(0, kick2) + SoundSamples(max(timeSamples.size - kickLen, 0)) {0}) / 1.5f;
     }
 }

src/main/kotlin/music/generators/Generator.kt

@@ -1,11 +1,10 @@
 package music.generators
 
-import music.Samples
-import music.Signal
-import music.WaveformTransformation
+import music.TimeSamples
+import music.SoundSamples
 
 interface Generator {
-    fun get(samples: Samples): Signal
+    fun get(timeSamples: TimeSamples): SoundSamples
 }
 
 

src/main/kotlin/music/generators/ToneGenerator.kt

@@ -1,22 +1,18 @@
 package music.generators
 
-import music.Samples
-import music.Signal
+import music.TimeSamples
+import music.SoundSamples
 import music.WaveformTransformation
 import music.filter.EaseFilter
 import music.times
 import kotlin.math.pow
-import kotlin.math.sign
 
 open class ToneGenerator(private val volume: Float, private val tone: Int, private val waveform: WaveformTransformation) : Generator {
-    override fun get(samples: Samples): Signal {
-        return applyEffects(waveform.apply(generate(samples), volume))
-    }
 
-    protected open fun applyEffects(signal: Signal): Signal = signal
+    override fun get(timeSamples: TimeSamples): SoundSamples =
+            applyEffects(waveform.apply(timeSamples * getFreqOfTone(tone), volume))
 
-    protected open fun generate(samples: Samples): Samples =
-        samples * getFreqOfTone(tone)
+    protected open fun applyEffects(soundSamples: SoundSamples): SoundSamples = soundSamples
 
     protected fun getFreqOfTone(tone: Float): Float =
         F0 * 2f.pow(tone / 12f)
@@ -30,6 +26,6 @@ open class ToneGenerator(private val volume: Float, private val tone: Int, priva
 }
 
 class EasedToneGenerator(volume: Float, tone: Int, waveform: WaveformTransformation) : ToneGenerator(volume, tone, waveform) {
-    override fun applyEffects(signal: Signal): Signal =
-         EaseFilter.INOUT.stream(signal)
+    override fun applyEffects(soundSamples: SoundSamples): SoundSamples =
+         EaseFilter.INOUT.stream(soundSamples)
 }