diff --git a/source/funkin/backend/utils/AudioAnalyzer.hx b/source/funkin/backend/utils/AudioAnalyzer.hx index 91b66f7b..e6163977 100644 --- a/source/funkin/backend/utils/AudioAnalyzer.hx +++ b/source/funkin/backend/utils/AudioAnalyzer.hx @@ -99,11 +99,6 @@ final class AudioAnalyzer { */ public var fftN(default, set):Int; - /** - * Whether or not should it also use the 4-point butterfly functions for FFT. - */ - public var allow4PointFFT:Bool = false; - /** * The current buffer from sound. */ @@ -149,7 +144,6 @@ final class AudioAnalyzer { var __twiddleImags:Array = []; var __freqReals:Array = []; var __freqImags:Array = []; - var __factors:Array = []; // levels var __frequencies:Array; @@ -201,19 +195,6 @@ final class AudioAnalyzer { __twiddleImags[i] = Math.sin(a); } - __factors.resize(0); - - var n = fftN; - while (n % 4 == 0) { - __factors.push(2); - n >>= 2; - } - - while (n % 2 == 0) { - __factors.push(1); - n >>= 1; - } - return fftN; } @@ -255,71 +236,6 @@ final class AudioAnalyzer { * @return Output of frequencies */ public function getFrequencies(startPos:Float, ?frequencies:Array):Array { - // https://github.com/FunkinCrew/grig.audio/commit/8567c4dad34cfeaf2ff23fe12c3796f5db80685e - inline function butterfly4PointOptimized(i0:Int, i1:Int, i2:Int, i3:Int, t1:Int, t2:Int, t3:Int) { - // Load input values - var x0r = __freqReals[i0]; - var x0i = __freqImags[i0]; - - // Apply twiddle factors to x1, x2, x3 - // x1 = workingData[i1] * twiddle1 - var x1r_raw = __freqReals[i1]; - var x1i_raw = __freqImags[i1]; - var tw1r = __twiddleReals[t1]; - var tw1i = __twiddleImags[t1]; - var x1r = x1r_raw * tw1r - x1i_raw * tw1i; - var x1i = x1r_raw * tw1i + x1i_raw * tw1r; - - // x2 = workingData[i2] * twiddle2 - var x2r_raw = __freqReals[i2]; - var x2i_raw = __freqImags[i2]; - var tw2r = __twiddleReals[t2]; - var tw2i = __twiddleImags[t2]; - var x2r = x2r_raw * tw2r - x2i_raw * tw2i; - var x2i = x2r_raw * tw2i + x2i_raw * tw2r; - - // x3 = workingData[i3] * twiddle3 - var x3r_raw = __freqReals[i3]; - var x3i_raw = __freqImags[i3]; - var tw3r = __twiddleReals[t3]; - var tw3i = __twiddleImags[t3]; - var x3r = x3r_raw * tw3r - x3i_raw * tw3i; - var x3i = x3r_raw * tw3i + x3i_raw * tw3r; - - // Compute intermediate values for 4-point DFT - var t0r = x0r + x2r; // (x0 + x2).real - var t0i = x0i + x2i; // (x0 + x2).imag - var t1r = x0r - x2r; // (x0 - x2).real - var t1i = x0i - x2i; // (x0 - x2).imag - var t2r = x1r + x3r; // (x1 + x3).real - var t2i = x1i + x3i; // (x1 + x3).imag - var t3r = x1r - x3r; // (x1 - x3).real - var t3i = x1i - x3i; // (x1 - x3).imag - - // Apply j multiplication: j * (a + jb) = -b + ja - var jt3r = -t3i; // j * t3.real = -t3.imag - var jt3i = t3r; // j * t3.imag = t3.real - - // Final 4-point DFT butterfly outputs - __freqReals[i0] = t0r + t2r; // X[k] - __freqImags[i0] = t0i + t2i; - __freqReals[i1] = t1r - jt3r; // X[k + N/4] - __freqImags[i1] = t1i - jt3i; - __freqReals[i2] = t0r - t2r; // X[k + N/2] - __freqImags[i2] = t0i - t2i; - __freqReals[i3] = t1r + jt3r; // X[k + 3N/4] - __freqImags[i3] = t1i + jt3i; - } - - inline function butterfly2PointOptimized(i0:Int, i1:Int, t:Int) { - var tempr = __freqReals[i1] * __twiddleReals[t] - __freqImags[i1] * __twiddleImags[t]; - var tempi = __freqReals[i1] * __twiddleImags[t] + __freqImags[i1] * __twiddleReals[t]; - __freqReals[i1] = __freqReals[i0] - tempr; - __freqImags[i1] = __freqImags[i0] - tempi; - __freqReals[i0] += tempr; - __freqImags[i0] += tempi; - } - __freqSamples = getSamples(startPos, fftN, true, __freqSamples); if (frequencies == null) frequencies = []; @@ -332,46 +248,32 @@ final class AudioAnalyzer { __freqImags[i] = 0; } - var size = 1, n = fftN, half, k, temp; - if (allow4PointFFT) for (factor in __factors) { - half = (size <<= factor) >> factor; - n >>= factor; + var size = 1, n = fftN, half = 1, k, i0, i1, t, tr:Float, ti:Float; + while ((size <<= 1) < fftN) { + n >>= 1; i = 0; while (i < fftN) { k = 0; while (k < half) { - if (factor == 2) - butterfly4PointOptimized(temp = i + k, temp += half, temp += half, temp += half, - (k * n) % fftN, (2 * k * n) % fftN, (3 * k * n) % fftN); - else - butterfly2PointOptimized(temp = i + k, temp += half, (k * n) % fftN); + i1 = (i0 = i + k) + half; + t = (k * n) % fftN; + + tr = __freqReals[i1] * __twiddleReals[t] - __freqImags[i1] * __twiddleImags[t]; + ti = __freqReals[i1] * __twiddleImags[t] + __freqImags[i1] * __twiddleReals[t]; + __freqReals[i1] = __freqReals[i0] - tr; + __freqImags[i1] = __freqImags[i0] - ti; + __freqReals[i0] += tr; + __freqImags[i0] += ti; k++; } i += size; } - } - else { - half = 1; - n = fftN; - while ((size <<= 1) < fftN) { - n >>= 1; - i = 0; - while (i < fftN) { - k = 0; - while (k < half) { - butterfly2PointOptimized(temp = i + k, temp += half, (k * n) % fftN); - k++; - } - i += size; - } - half = size; - } + half = size; } - var inv = 1.0 / fftN; - frequencies[i = 0] = Math.sqrt(__freqReals[0] * __freqReals[0] + __freqImags[0] * __freqImags[0]) * inv; - while (++i < __N2) frequencies[i] = 2 * Math.sqrt(__freqReals[i] * __freqReals[i] + __freqImags[i] * __freqImags[i]) * inv; + frequencies[i = 0] = Math.sqrt(__freqReals[0] * __freqReals[0] + __freqImags[0] * __freqImags[0]) * (tr = 1.0 / fftN); + while (++i < __N2) frequencies[i] = 2 * Math.sqrt(__freqReals[i] * __freqReals[i] + __freqImags[i] * __freqImags[i]) * tr; return frequencies; }