Method runNaive

src/fl/audio/fft/fft_impl.cpp.hpp:295–331

    }

    void runNaive(span<const i16> buffer, Bins *out) {
        out->setParams(mFmin, mFmax, mSampleRate);
        const int fftSize = mInputSamples;
        const int numRawBins = fftSize / 2 + 1;

        FftScratch &s = scratch();
        s.fftOut.resize(fftSize);
        s.re.resize(numRawBins);
        s.im.resize(numRawBins);
        s.mag.resize(numRawBins);

        fl_fft_real_forward(mFftrCfg, mInputSamples, buffer.data(), s.fftOut.data());

        // Deinterleave AoS → SoA and batch-compute magnitudes
        deinterleave(s.fftOut.data(), s.re.data(), s.im.data(), numRawBins);
        batchMag(s.re.data(), s.im.data(), s.mag.data(), numRawBins);

        computeLinearBins(s.mag.data(), fftSize, out);

        FASTLED_STACK_ARRAY(kiss_fft_cpx, cq, mCqCfg.bands);
        apply_kernels(s.fftOut.data(), cq, mKernels, mCqCfg);

        const int bands = mCqCfg.bands;
        fl::vector<float> &rawBins = out->raw_mut();
        rawBins.resize(bands);
        for (int i = 0; i < bands; ++i) {
            i32 real = cq[i].r;
            i32 imag = cq[i].i;
#ifdef FIXED_POINT
            rawBins[i] = static_cast<float>(fastMag(real, imag));
#else
            float r2 = float(real * real);
            float i2 = float(imag * imag);
            rawBins[i] = sqrt(r2 + i2);
#endif
        }
    }

    // Fast integer magnitude: max(|re|,|im|) + 0.40625*min(|re|,|im|)
    // Max error ~3.5% vs exact sqrt(re²+im²). No float, no division.