diff options
Diffstat (limited to 'mvcf~.c')
| -rw-r--r-- | mvcf~.c | 172 |
1 files changed, 172 insertions, 0 deletions
@@ -0,0 +1,172 @@ +/* + * moog vcf, 4-pole lowpass resonant filter + * + * (c) Edward Kelly 2012 + * BSD License + */ +#include "m_pd.h" +#include <math.h> +#define _limit 0.95 + +static t_class *mvcf_tilde_class; + +typedef struct _mvcf_tilde { + t_object x_obj; + t_float b0, b1, b2, b3, b4; //filter buffers to keep (beware denormals!) + t_float token, debug, safety; + t_outlet *lp; +} t_mvcf_tilde; + +/* We could have a mode where the fc and res are only registered at the start of the block (quick) or are registered in signal mode (slow) - i.e. a flag */ + + +static inline float saturate( float input ) { //clamp without branching + float x1 = fabsf( input + _limit ); + float x2 = fabsf( input - _limit ); + return 0.5 * (x1 - x2); +} + + +t_int *mvcf_tilde_perform(t_int *w) { + t_mvcf_tilde *x = (t_mvcf_tilde *)(w[1]); + t_sample *in = (t_sample *)(w[2]); + t_sample *fc = (t_sample *)(w[3]); + t_sample *res = (t_sample *)(w[4]); + t_sample *out = (t_sample *)(w[5]); + int n = (int)(w[6]); + + //x *b0 = + + /* + q = 1.0f - frequency; + p = frequency + 0.8f * frequency * q; + f = p + p - 1.0f; + q = resonance * (1.0f + 0.5f * q * (1.0f - q + 5.6f * q * q)); + */ + + // while (n--) { + // float f = *(in++); + // setup_svf(obj, *(freq++), *(res++)); + // *(out++) = run_svf(obj, f + ((obj->b) * (*(res++)))); + // } + + float t1 = 0; + float t2 = 0; + float xb0 = x->b0; + float xb1 = x->b1; + float xb2 = x->b2; + float xb3 = x->b3; + float xb4 = x->b4; + float i1 = 0; + float fc1 = 0; + float res1 = 0; + float q = 0; + float p = 0; + float fcoeff = 0; + + // while (n-=4) { + while (n--) { + i1=(*in++); + fc1 = (*fc++); + /* This failsafe line stops the filter bursting + * ...but it is expensive! */ + if(x->safety) { + fc1 = fc1 <= 1 ? fc1 >= 0 ? fc1 : 0 : 1; + } + res1 = (*res++); + q = 1.0f - fc1; + p = fc1 + 0.8f * fc1 * q; + fcoeff = p + p - 1.0f; + q = res1 * (1.0f + 0.5f * q * (1.0f - q + 5.6f * q * q)); + i1 -= q * xb4; //feedback + t1 = xb1; + xb1 = (i1 + xb0) * p - xb1 * fcoeff; + t2 = xb2; + xb2 = (xb1 + t1) * p - xb2 * fcoeff; + t1 = xb3; + xb3 = (xb2 + t2) * p - xb3 * fcoeff; + xb4 = (xb3 + t1) * p - xb4 * fcoeff; + xb4 = saturate(xb4); + xb4 = xb4 - xb4 * xb4 * xb4 * 0.01f; + xb0 = i1; + *out++ = xb4; // lowpass mode + // *out++ = i1 - x->b4; // highpass mode +// Lowpass output: xb4 +// Highpass output: in - xb4; +// Bandpass output: 3.0f * (b3 - xb4); + + } + x->b0 = xb0; + x->b1 = xb1; + x->b2 = xb2; + x->b3 = xb3; + x->b4 = xb4; + if(x->debug != 0) { + x->token +=1; + if(x->token == 15) { + post("q = %f, p=%f, fcoeff=%f, b0=%f, b1=%f, b2=%f, b3=%f, b4=%f",q,p,fcoeff,xb0,xb1,xb2,xb3,xb4); + x->token = 0; + } + } + return (w+7); +} + +void mvcf_tilde_dsp(t_mvcf_tilde *x, t_signal **sp) { + dsp_add(mvcf_tilde_perform, 6, x, sp[0]->s_vec, sp[1]->s_vec, sp[2]->s_vec, sp[3]->s_vec, sp[0]->s_n); +} + +void mvcf_tilde_safety(t_mvcf_tilde *x, t_floatarg f) { + x->safety = f != 0 ? 1 : 0; +} + +/*void mvcf_tilde_mode(t_mvcf_tilde *x, t_floatarg f) { +x->mode = f < 1 ? 0 : f > 1 ? 2 : 1; +} + */ + +void mvcf_tilde_clear(t_mvcf_tilde *x) { + x->b0 = 0; + x->b1 = 0; + x->b2 = 0; + x->b3 = 0; + x->b4 = 0; +} + +void mvcf_tilde_debug(t_mvcf_tilde *x, t_floatarg f) { + x->debug = f != 0 ? 1 : 0; +} + +void *mvcf_tilde_new(t_floatarg f) { + t_mvcf_tilde *x = (t_mvcf_tilde *)pd_new(mvcf_tilde_class); + + x->b0 = 0; + x->b1 = 0; + x->b2 = 0; + x->b3 = 0; + x->b4 = 0; + x->token = 0; + x->safety = 1; + + inlet_new (&x->x_obj, &x->x_obj.ob_pd, &s_signal, &s_signal); + inlet_new (&x->x_obj, &x->x_obj.ob_pd, &s_signal, &s_signal); + outlet_new(&x->x_obj, &s_signal); + return (void *)x; +} + +void mvcf_tilde_setup(void) { + mvcf_tilde_class = class_new(gensym("mvcf~"), + (t_newmethod)mvcf_tilde_new, + 0, sizeof(t_mvcf_tilde), + CLASS_DEFAULT, A_DEFFLOAT, 0); + + post("~~~~~~~~~~~~~~~>mvcf~"); + post("~~~>by Ed Kelly, 2012"); + + class_addmethod(mvcf_tilde_class, + (t_method)mvcf_tilde_dsp, gensym("dsp"), 0); + CLASS_MAINSIGNALIN(mvcf_tilde_class, t_mvcf_tilde, token); + class_addmethod(mvcf_tilde_class, (t_method)mvcf_tilde_clear, gensym("clear"), 0); + class_addmethod(mvcf_tilde_class, (t_method)mvcf_tilde_debug, gensym("debug"), 0); + class_addmethod(mvcf_tilde_class, (t_method)mvcf_tilde_safety, gensym("safe"), 0); + // class_addmethod(mvcf_tilde_class, (t_method)mvcf_tilde_mode, gensym("mode"), A_DEFFLOAT, 0); +} |