src/sigil/dsp/osc.sgl

1;;; (sigil dsp osc) - Oscillators

2;;;

3;;; Wavetable, bandlimited, FM, and phase oscillators.

4;;;

5;;; ```scheme

6;;; (import (sigil dsp core) (sigil dsp osc))

7;;; (dsp-init)

8;;; (define osc (make-oscillator 'sine 440.0 0.5))

9;;; (osc-compute osc) ; => one sample

10;;; ```

12(define-library (sigil dsp osc)

13 (export

14 make-oscillator

15 make-osc make-osc-ft osc-compute osc-set-freq! osc-set-amp!

16 make-posc3 posc3-compute posc3-set-freq! posc3-set-amp!

17 make-blsaw blsaw-compute blsaw-set-freq! blsaw-set-amp!

18 make-blsquare blsquare-compute blsquare-set-freq! blsquare-set-amp!

19 make-bltriangle bltriangle-compute bltriangle-set-freq! bltriangle-set-amp!

20 make-fosc fosc-compute fosc-set-freq! fosc-set-index! fosc-set-amp!

21 make-phasor phasor-compute phasor-set-freq!

22 make-ks ks-compute ks-trigger!

23 ks-set-freq! ks-set-decay! ks-set-excite-gain!)

25 (begin

26 (define-native make-osc)

27 (define-native make-osc-ft)

28 (define-native (osc-compute osc))

29 (define-native (osc-set-freq! osc freq))

30 (define-native (osc-set-amp! osc amp))

31 (define-native make-posc3)

32 (define-native (posc3-compute osc))

33 (define-native (posc3-set-freq! osc freq))

34 (define-native (posc3-set-amp! osc amp))

35 (define-native (make-blsaw freq amp))

36 (define-native (blsaw-compute osc))

37 (define-native (blsaw-set-freq! osc freq))

38 (define-native (blsaw-set-amp! osc amp))

39 (define-native make-blsquare)

40 (define-native (blsquare-compute osc))

41 (define-native (blsquare-set-freq! osc freq))

42 (define-native (blsquare-set-amp! osc amp))

43 (define-native (make-bltriangle freq amp))

44 (define-native (bltriangle-compute osc))

45 (define-native (bltriangle-set-freq! osc freq))

46 (define-native (bltriangle-set-amp! osc amp))

47 (define-native (make-fosc freq car mod indx amp))

48 (define-native (fosc-compute osc))

49 (define-native (fosc-set-freq! osc freq))

50 (define-native (fosc-set-index! osc indx))

51 (define-native (fosc-set-amp! osc amp))

52 (define-native make-phasor)

53 (define-native (phasor-compute phasor))

54 (define-native (phasor-set-freq! phasor freq))

55 (define-native (make-ks freq decay excite-gain))

56 (define-native (ks-compute ks gate))

57 (define-native (ks-trigger! ks))

58 (define-native (ks-set-freq! ks freq))

59 (define-native (ks-set-decay! ks decay))

60 (define-native (ks-set-excite-gain! ks gain))

62 ;;; Create an oscillator by type.

63 ;;; Types: sine, saw, square, triangle, fm

64 (define (make-oscillator type freq amp . opts)

65 (case type

66 ((sine) (make-osc freq amp))

67 ((saw) (make-blsaw freq amp))

68 ((square) (if (null? opts)

69 (make-blsquare freq amp)

70 (make-blsquare freq amp (car opts))))

71 ((triangle) (make-bltriangle freq amp))

72 ((fm) (if (>= (length opts) 2)

73 (make-fosc freq (car opts) (cadr opts)

74 (if (>= (length opts) 3) (caddr opts) 1.0)

75 amp)

76 (error "make-oscillator: fm requires car and mod ratios" opts)))

77 (else (error "make-oscillator: unknown type" type))))))