From f11ea557be591279db51898a4bd1677ac2f371ad Mon Sep 17 00:00:00 2001
From: minjaesong <alswo9628@gmail.com>
Date: Sun, 29 Jun 2025 19:29:02 +0900
Subject: [PATCH] reverting FFT changes

---
 src/net/torvald/terrarum/audio/FFT.kt         | 10 +++++-----
 src/net/torvald/terrarum/audio/dsp/Convolv.kt | 16 +++++++++++++++-
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/net/torvald/terrarum/audio/FFT.kt b/src/net/torvald/terrarum/audio/FFT.kt
index 993e65436..5164b2259 100644
--- a/src/net/torvald/terrarum/audio/FFT.kt
+++ b/src/net/torvald/terrarum/audio/FFT.kt
@@ -92,26 +92,26 @@ object FFT: Disposable {
 
     fun fft(signal0: FloatArray): ComplexArray {
         val signal = FloatArray(signal0.size * 2) { if (it % 2 == 0) signal0[it / 2] else 0f }
-        ffts[signal0.size]!!.realForward(signal)
+        ffts[signal0.size]!!.complexForward(signal)
         return ComplexArray(signal)
     }
 
     fun fft(signal0: ComplexArray) {
-        ffts[signal0.size]!!.realForward(signal0.reim)
+        ffts[signal0.size]!!.complexForward(signal0.reim)
     }
 
     fun fftInto(signal0: ComplexArray, out: ComplexArray) {
         System.arraycopy(signal0.reim, 0, out.reim, 0, signal0.reim.size)
-        ffts[signal0.size]!!.realForward(out.reim)
+        ffts[signal0.size]!!.complexForward(out.reim)
     }
 
     fun ifftAndGetReal(signal0: ComplexArray): FloatArray {
-        ffts[signal0.size]!!.realInverse(signal0.reim, true)
+        ffts[signal0.size]!!.complexInverse(signal0.reim, true)
         return signal0.getReal()
     }
 
     fun ifftAndGetReal(signal0: ComplexArray, output: FloatArray) {
-        ffts[signal0.size]!!.realInverse(signal0.reim, true)
+        ffts[signal0.size]!!.complexInverse(signal0.reim, true)
         for (i in 0 until signal0.size) {
             output[i] = signal0.reim[i * 2]
         }
diff --git a/src/net/torvald/terrarum/audio/dsp/Convolv.kt b/src/net/torvald/terrarum/audio/dsp/Convolv.kt
index a4f8f041b..396097bcd 100644
--- a/src/net/torvald/terrarum/audio/dsp/Convolv.kt
+++ b/src/net/torvald/terrarum/audio/dsp/Convolv.kt
@@ -62,7 +62,7 @@ class Convolv(irModule: String, irPath: String, val crossfeed: Float, gain: Floa
 
 
 
-        pushSumCircular(gain, inbuf[0], inbuf[1], sumbuf)
+        pushSum(gain, inbuf[0], inbuf[1], sumbuf)
 
         convolve(sumbuf[0], convFFT[0], fftOutL)
         convolve(sumbuf[1], convFFT[1], fftOutR)
@@ -79,6 +79,20 @@ class Convolv(irModule: String, irPath: String, val crossfeed: Float, gain: Floa
         processingSpeed = realtime / ptime
     }
 
+    private fun pushSum(gain: Float, sampleL: FloatArray, sampleR: FloatArray, sumbuf: Array<ComplexArray>) {
+        // shift numbers
+        System.arraycopy(sumbuf[0].reim, sampleL.size * 2, sumbuf[0].reim, 0, sumbuf[0].reim.size - sampleL.size * 2)
+        System.arraycopy(sumbuf[1].reim, sampleL.size * 2, sumbuf[1].reim, 0, sumbuf[1].reim.size - sampleL.size * 2)
+        // fill in the shifted area
+        val baseI = sumbuf[0].reim.size - sampleL.size * 2
+        for (index in sampleL.indices) {
+            sumbuf[0].reim[baseI + index * 2 + 0] = (sampleL[index] * 1.000000f + sampleR[index] * crossfeed) * gain
+            sumbuf[0].reim[baseI + index * 2 + 1] = 0f
+            sumbuf[1].reim[baseI + index * 2 + 0] = (sampleL[index] * crossfeed + sampleR[index] * 1.000000f) * gain
+            sumbuf[1].reim[baseI + index * 2 + 1] = 0f
+        }
+    }
+
     private var bufferIndex = 0
     private fun pushSumCircular(gain: Float, sampleL: FloatArray, sampleR: FloatArray, sumbuf: Array<ComplexArray>) {
         val baseIdx = bufferIndex * 2