You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

90 lines
2.8KB

  1. // Copyright 2014 Olivier Gillet.
  2. //
  3. // Author: Olivier Gillet (ol.gillet@gmail.com)
  4. //
  5. // Permission is hereby granted, free of charge, to any person obtaining a copy
  6. // of this software and associated documentation files (the "Software"), to deal
  7. // in the Software without restriction, including without limitation the rights
  8. // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  9. // copies of the Software, and to permit persons to whom the Software is
  10. // furnished to do so, subject to the following conditions:
  11. //
  12. // The above copyright notice and this permission notice shall be included in
  13. // all copies or substantial portions of the Software.
  14. //
  15. // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16. // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17. // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18. // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19. // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20. // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  21. // THE SOFTWARE.
  22. //
  23. // See http://creativecommons.org/licenses/MIT/ for more information.
  24. //
  25. // -----------------------------------------------------------------------------
  26. //
  27. // Simple waveguide tube.
  28. #include "elements/dsp/tube.h"
  29. #include <cstdio>
  30. #include "stmlib/dsp/dsp.h"
  31. #include "stmlib/utils/random.h"
  32. namespace elements {
  33. void Tube::Init() {
  34. zero_state_ = 0.0f;
  35. pole_state_ = 0.0f;
  36. delay_ptr_ = 0;
  37. }
  38. void Tube::Process(
  39. float frequency,
  40. float envelope,
  41. float damping,
  42. float timbre,
  43. float* input_output,
  44. float gain,
  45. size_t size) {
  46. float delay = 1.0f / frequency;
  47. while (delay >= float(kTubeDelaySize)) {
  48. delay *= 0.5f;
  49. }
  50. MAKE_INTEGRAL_FRACTIONAL(delay);
  51. if (envelope >= 1.0f) envelope = 1.0f;
  52. damping = 3.6f - damping * 1.8f;
  53. float lpf_coefficient = frequency * (1.0f + timbre * timbre * 256.0f);
  54. if (lpf_coefficient >= 0.995f) lpf_coefficient = 0.995f;
  55. int32_t d = delay_ptr_;;
  56. while (size--) {
  57. float breath = *input_output * damping + 0.8f;
  58. float a = delay_line_[(d + delay_integral) % kTubeDelaySize];
  59. float b = delay_line_[(d + delay_integral + 1) % kTubeDelaySize];
  60. float in = a + (b - a) * delay_fractional;
  61. float pressure_delta = -0.95f * (in * envelope + zero_state_) - breath;
  62. zero_state_ = in;
  63. float reed = pressure_delta * -0.2f + 0.8f;
  64. float out = pressure_delta * reed + breath;
  65. CONSTRAIN(out, -5.0f, 5.0f);
  66. delay_line_[d] = out * 0.5f;
  67. --d;
  68. if (d < 0) {
  69. d = kTubeDelaySize - 1;
  70. }
  71. pole_state_ += lpf_coefficient * (out - pole_state_);
  72. *input_output++ += gain * envelope * pole_state_;
  73. }
  74. delay_ptr_ = d;
  75. }
  76. } // namespace elements