Method shape

src/core/ClientTube.cpp:177–203

}

float ClientTube::shape(float x) const noexcept
{
    const float bias = m_cached.bias;
    // Asymmetric term — always non-negative, produces DC offset +
    // even harmonics.  tanh-bounded so it never blows up at high
    // drive; peak contribution capped at ±bias.
    const float asym = bias * std::tanh(x * x);
    switch (m_cached.model) {
        case static_cast<uint8_t>(Model::A):   // soft tanh
            return std::tanh(x) + asym;
        case static_cast<uint8_t>(Model::B): { // hard clip + tanh hybrid
            // Hard clip at ±1 followed by tanh softening — gives a
            // stronger odd-harmonic character than pure tanh.
            const float h = std::clamp(x, -1.0f, 1.0f);
            return std::tanh(h * 1.3f) * 0.85f + asym;
        }
        case static_cast<uint8_t>(Model::C): { // asymmetric-dominant
            // tanh-bounded asymmetric shaper — stronger even-harmonic
            // content than A/B without the unbounded growth of raw
            // x² terms.
            const float t  = std::tanh(x);
            const float a2 = std::tanh(x * x);
            return 0.75f * t + (0.35f + 0.65f * bias) * a2;
        }
    }
    return std::tanh(x);
}

void ClientTube::process(float* interleaved, int frames, int channels) noexcept
{