Function fast_sine

perro_source/audio_stack/perro_pawdio/src/midi.rs:549–561

(phase: f32)

            self.release_gain -= RELEASE_STEP;
        }
        if self.release_gain <= 0.0 {
            return None;
        }

        let raw = match self.wave {
            WaveKind::Sine => fast_sine(sine, self.phase),
            WaveKind::Square => {
                if self.phase < std::f32::consts::PI {
                    1.0
                } else {
                    -1.0
                }
            }
            WaveKind::Saw => (self.phase / TAU) * 2.0 - 1.0,
            WaveKind::Triangle => {
                let t = self.phase / TAU;