Line data    Source code

       1              : #pragma once
       2              : 
       3              : // Hard-clipping distortion effect with tone shaping.
       4              : // The driven sample u=drive*x[n] is clipped with y=clamp(u, -clip, clip), then
       5              : // filtered by the tone stage and level-scaled; this creates odd harmonics as
       6              : // the transfer function flattens near the clipping threshold.
       7              : 
       8              : #include "audio/dsp/biquad.h"
       9              : #include "audio/effects/core/effect.h"
      10              : 
      11              : namespace Amplitron {
      12              : 
      13            2 : class Distortion : public Effect {
      14              :    public:
      15              :     // Create a distortion effect with drive, tone, and output gain controls.
      16              :     Distortion();
      17              :     // Apply the distortion curve and filtering to a mono audio buffer.
      18              :     void process(float* buffer, int num_samples) override;
      19              :     // Clear any filter state held by the effect.
      20              :     void reset() override;
      21              :     // Return the display name for this effect.
      22          131 :     const char* name() const override { return "Distortion"; }
      23            3 :     const char* type_id() const override { return "Distortion"; }
      24              :     // Return editable parameters exposed by this effect.
      25          114 :     std::vector<EffectParam>& params() override { return params_; }
      26            3 :     const std::vector<EffectParam>& params() const override { return params_; }
      27              : 
      28              :    private:
      29              :     std::vector<EffectParam> params_;
      30              :     OnePole tone_lp_;
      31              : 
      32              :     // One-pole smoothing states (avoids zipper noise on parameter changes)
      33              :     float drive_smoothed_ = 2.0f;
      34              :     float tone_smoothed_ = 0.6f;
      35              :     float level_smoothed_ = 0.5f;
      36              : };
      37              : 
      38              : }  // namespace Amplitron