513389b4c1
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21044 a1c6a512-1295-4272-9138-f99709370657
452 lines
11 KiB
C
452 lines
11 KiB
C
/* (C) Guenter Geiger <geiger@epy.co.at> */
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#include <m_pd.h>
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#include <math.h>
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#ifdef NT
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#pragma warning( disable : 4244 )
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#pragma warning( disable : 4305 )
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#endif
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/* ------------------------ hlshelf ----------------------------- */
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#ifndef M_PI
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#define M_PI 3.141593f
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#endif
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#define SRATE 44100.0
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#define MAX_GAIN 120.0f
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static t_class *hlshelf_class;
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typedef struct _hlshelf
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{
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t_object x_obj;
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float s_rate;
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float s_gain0;
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float s_gain1;
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float s_gain2;
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float s_ltransfq;
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float s_htransfq;
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float s_lradians;
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float s_hradians;
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} t_hlshelf;
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int hlshelf_check_stability(t_float fb1,
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t_float fb2,
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t_float ff1,
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t_float ff2,
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t_float ff3)
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{
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float discriminant = fb1 * fb1 + 4 * fb2;
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if (discriminant < 0) /* imaginary roots -- resonant filter */
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{
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/* they're conjugates so we just check that the product
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is less than one */
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if (fb2 >= -1.0f) goto stable;
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}
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else /* real roots */
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{
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/* check that the parabola 1 - fb1 x - fb2 x^2 has a
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vertex between -1 and 1, and that it's nonnegative
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at both ends, which implies both roots are in [1-,1]. */
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if (fb1 <= 2.0f && fb1 >= -2.0f &&
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1.0f - fb1 -fb2 >= 0 && 1.0f + fb1 - fb2 >= 0)
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goto stable;
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}
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return 0;
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stable:
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return 1;
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}
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void hlshelf_check(t_hlshelf *x)
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{
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if(x->s_gain0 - x->s_gain1 > MAX_GAIN) {
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x->s_gain0 = x->s_gain1 + MAX_GAIN;
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post("setting gain0 to %f",x->s_gain0);
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}
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if(x->s_gain1 > MAX_GAIN) {
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x->s_gain1 = MAX_GAIN;
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post("setting gain1 to %f",x->s_gain1);
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}
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if(x->s_gain2 - x->s_gain1 > MAX_GAIN) {
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x->s_gain2 = x->s_gain1 + MAX_GAIN;
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post("setting gain2 to %f",x->s_gain2);
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}
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/* constrain: 0 <= x->s_ltransfq < x->s_htransfq. */
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x->s_ltransfq = (x->s_ltransfq < x->s_htransfq) ? x->s_ltransfq : x->s_htransfq - 0.5f;
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if (x->s_ltransfq < 0) x->s_ltransfq = 0.0f;
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x->s_lradians = M_PI * x->s_ltransfq / x->s_rate;
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x->s_hradians= M_PI * (0.5f - (x->s_htransfq / x->s_rate));
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}
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void hlshelf_bang(t_hlshelf *x)
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{
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t_atom at[6];
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float c0, c1, c2, d0, d1, d2; /* output coefs */
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float a1, a2, b1, b2, g1, g2; /* temp coefs */
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double xf;
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hlshelf_check(x);
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/* low shelf */
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xf = 0.5 * 0.115129255 * (double)(x->s_gain0 - x->s_gain1); /* ln(10) / 20 = 0.115129255 */
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if(xf < -200.) /* exp(x) -> 0 */
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{
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a1 = 1.0f;
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b1 = -1.0f;
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g1 = 0.0f;
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}
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else
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{
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double t = tan(x->s_lradians);
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double e = exp(xf);
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double r = t / e;
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double kr = t * e;
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a1 = (r - 1) / (r + 1);
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b1 = (kr - 1) / (kr + 1);
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g1 = (kr + 1) / (r + 1);
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}
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/* high shelf */
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xf = 0.5 * 0.115129255 * (double)(x->s_gain2 - x->s_gain1); /* ln(10) / 20 = 0.115129255 */
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if(xf < -200.) /* exp(x) -> 0 */
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{
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a2 = -1.0f;
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b2 = 1.0f;
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g2 = 0.0f;
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}
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else
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{
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double t = tan(x->s_hradians);
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double e = exp(xf);
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double r = t / e;
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double kr = t * e;
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a2 = (1 - r) / (1 + r);
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b2 = (1 - kr) / (1 + kr);
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g2 = (1 + kr) / (1 + r);
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}
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/* form product */
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c0 = g1 * g2 * (float)(exp((double)(x->s_gain1) * 0.05f * 2.302585093f)); ;
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c1 = a1 + a2;
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c2 = a1 * a2;
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d0 = 1.0f;
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d1 = b1 + b2;
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d2 = b1 * b2;
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if (!hlshelf_check_stability(-c1/d0,-c2/d0,d0/d0,d1/d0,d2/d0)) {
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post("hlshelf: filter unstable -> resetting");
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c0=1.;c1=0.;c2=0.;
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d0=1.;d1=0.;d2=0.;
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}
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SETFLOAT(at,-c1/d0);
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SETFLOAT(at+1,-c2/d0);
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SETFLOAT(at+2,d0/d0);
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SETFLOAT(at+3,d1/d0);
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SETFLOAT(at+4,d2/d0);
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outlet_list(x->x_obj.ob_outlet,&s_list,5,at);
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}
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void hlshelf_float(t_hlshelf *x,t_floatarg f)
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{
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x->s_gain0 = f;
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hlshelf_bang(x);
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}
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static void *hlshelf_new(t_symbol* s,t_int argc, t_atom* at)
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{
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t_hlshelf *x = (t_hlshelf *)pd_new(hlshelf_class);
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t_float k0 = atom_getfloat(at);
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t_float k1 = atom_getfloat(at+1);
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t_float k2 = atom_getfloat(at+2);
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t_float f1 = atom_getfloat(at+3);
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t_float f2 = atom_getfloat(at+4);
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f1 = atom_getfloat(at);
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f2 = atom_getfloat(at);
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if ((f1 == 0.0f && f2 == 0.0f) || f1 > f2){ /* all gains = 0db */
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f1 = 150.0f;
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f2 = 5000.0f;
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}
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if (f1 < 0) f1 = 0.0f;
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if (f2 > SRATE) f2 = .5f*SRATE;
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x->s_rate = SRATE; /* srate default */
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x->s_gain0 = k0;
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x->s_gain1 = k1;
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x->s_gain2 = k2;
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x->s_ltransfq = 0.0f;
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x->s_htransfq = SRATE/2;
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x->s_lradians = M_PI * x->s_ltransfq / x->s_rate;
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x->s_hradians= M_PI * (0.5f - (x->s_htransfq / x->s_rate));
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floatinlet_new(&x->x_obj, &x->s_gain1);
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floatinlet_new(&x->x_obj, &x->s_gain2);
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floatinlet_new(&x->x_obj, &x->s_ltransfq);
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floatinlet_new(&x->x_obj, &x->s_htransfq);
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outlet_new(&x->x_obj, &s_list);
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return (x);
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}
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void hlshelf_setup(void)
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{
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hlshelf_class = class_new(gensym("hlshelf"), (t_newmethod)hlshelf_new, 0,
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sizeof(t_hlshelf), 0, A_GIMME, 0);
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class_addbang(hlshelf_class,hlshelf_bang);
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class_addfloat(hlshelf_class,hlshelf_float);
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}
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/* (C) Guenter Geiger <geiger@epy.co.at> */
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#include <m_pd.h>
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#include <math.h>
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#ifdef NT
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#pragma warning( disable : 4244 )
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#pragma warning( disable : 4305 )
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#endif
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/* ------------------------ hlshelf ----------------------------- */
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#ifndef M_PI
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#define M_PI 3.141593f
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#endif
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#define SRATE 44100.0
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#define MAX_GAIN 120.0f
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static t_class *hlshelf_class;
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typedef struct _hlshelf
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{
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t_object x_obj;
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float s_rate;
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float s_gain0;
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float s_gain1;
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float s_gain2;
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float s_ltransfq;
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float s_htransfq;
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float s_lradians;
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float s_hradians;
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} t_hlshelf;
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int hlshelf_check_stability(t_float fb1,
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t_float fb2,
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t_float ff1,
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t_float ff2,
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t_float ff3)
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{
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float discriminant = fb1 * fb1 + 4 * fb2;
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if (discriminant < 0) /* imaginary roots -- resonant filter */
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{
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/* they're conjugates so we just check that the product
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is less than one */
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if (fb2 >= -1.0f) goto stable;
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}
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else /* real roots */
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{
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/* check that the parabola 1 - fb1 x - fb2 x^2 has a
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vertex between -1 and 1, and that it's nonnegative
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at both ends, which implies both roots are in [1-,1]. */
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if (fb1 <= 2.0f && fb1 >= -2.0f &&
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1.0f - fb1 -fb2 >= 0 && 1.0f + fb1 - fb2 >= 0)
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goto stable;
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}
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return 0;
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stable:
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return 1;
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}
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void hlshelf_check(t_hlshelf *x)
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{
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if(x->s_gain0 - x->s_gain1 > MAX_GAIN) {
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x->s_gain0 = x->s_gain1 + MAX_GAIN;
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post("setting gain0 to %f",x->s_gain0);
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}
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if(x->s_gain1 > MAX_GAIN) {
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x->s_gain1 = MAX_GAIN;
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post("setting gain1 to %f",x->s_gain1);
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}
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if(x->s_gain2 - x->s_gain1 > MAX_GAIN) {
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x->s_gain2 = x->s_gain1 + MAX_GAIN;
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post("setting gain2 to %f",x->s_gain2);
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}
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/* constrain: 0 <= x->s_ltransfq < x->s_htransfq. */
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x->s_ltransfq = (x->s_ltransfq < x->s_htransfq) ? x->s_ltransfq : x->s_htransfq - 0.5f;
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if (x->s_ltransfq < 0) x->s_ltransfq = 0.0f;
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x->s_lradians = M_PI * x->s_ltransfq / x->s_rate;
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x->s_hradians= M_PI * (0.5f - (x->s_htransfq / x->s_rate));
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}
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void hlshelf_bang(t_hlshelf *x)
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{
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t_atom at[6];
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float c0, c1, c2, d0, d1, d2; /* output coefs */
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float a1, a2, b1, b2, g1, g2; /* temp coefs */
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double xf;
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hlshelf_check(x);
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/* low shelf */
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xf = 0.5 * 0.115129255 * (double)(x->s_gain0 - x->s_gain1); /* ln(10) / 20 = 0.115129255 */
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if(xf < -200.) /* exp(x) -> 0 */
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{
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a1 = 1.0f;
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b1 = -1.0f;
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g1 = 0.0f;
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}
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else
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{
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double t = tan(x->s_lradians);
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double e = exp(xf);
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double r = t / e;
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double kr = t * e;
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a1 = (r - 1) / (r + 1);
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b1 = (kr - 1) / (kr + 1);
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g1 = (kr + 1) / (r + 1);
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}
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/* high shelf */
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xf = 0.5 * 0.115129255 * (double)(x->s_gain2 - x->s_gain1); /* ln(10) / 20 = 0.115129255 */
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if(xf < -200.) /* exp(x) -> 0 */
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{
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a2 = -1.0f;
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b2 = 1.0f;
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g2 = 0.0f;
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}
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else
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{
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double t = tan(x->s_hradians);
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double e = exp(xf);
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double r = t / e;
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double kr = t * e;
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a2 = (1 - r) / (1 + r);
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b2 = (1 - kr) / (1 + kr);
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g2 = (1 + kr) / (1 + r);
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}
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/* form product */
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c0 = g1 * g2 * (float)(exp((double)(x->s_gain1) * 0.05f * 2.302585093f)); ;
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c1 = a1 + a2;
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c2 = a1 * a2;
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d0 = 1.0f;
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d1 = b1 + b2;
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d2 = b1 * b2;
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if (!hlshelf_check_stability(-c1/d0,-c2/d0,d0/d0,d1/d0,d2/d0)) {
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post("hlshelf: filter unstable -> resetting");
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c0=1.;c1=0.;c2=0.;
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d0=1.;d1=0.;d2=0.;
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}
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SETFLOAT(at,-c1/d0);
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SETFLOAT(at+1,-c2/d0);
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SETFLOAT(at+2,d0/d0);
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SETFLOAT(at+3,d1/d0);
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SETFLOAT(at+4,d2/d0);
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outlet_list(x->x_obj.ob_outlet,&s_list,5,at);
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}
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void hlshelf_float(t_hlshelf *x,t_floatarg f)
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{
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x->s_gain0 = f;
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hlshelf_bang(x);
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}
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static void *hlshelf_new(t_symbol* s,t_int argc, t_atom* at)
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{
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t_hlshelf *x = (t_hlshelf *)pd_new(hlshelf_class);
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t_float k0 = atom_getfloat(at);
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t_float k1 = atom_getfloat(at+1);
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t_float k2 = atom_getfloat(at+2);
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t_float f1 = atom_getfloat(at+3);
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t_float f2 = atom_getfloat(at+4);
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f1 = atom_getfloat(at);
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f2 = atom_getfloat(at);
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if ((f1 == 0.0f && f2 == 0.0f) || f1 > f2){ /* all gains = 0db */
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f1 = 150.0f;
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f2 = 5000.0f;
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}
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if (f1 < 0) f1 = 0.0f;
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if (f2 > SRATE) f2 = .5f*SRATE;
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x->s_rate = SRATE; /* srate default */
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x->s_gain0 = k0;
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x->s_gain1 = k1;
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x->s_gain2 = k2;
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x->s_ltransfq = 0.0f;
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x->s_htransfq = SRATE/2;
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x->s_lradians = M_PI * x->s_ltransfq / x->s_rate;
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x->s_hradians= M_PI * (0.5f - (x->s_htransfq / x->s_rate));
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floatinlet_new(&x->x_obj, &x->s_gain1);
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floatinlet_new(&x->x_obj, &x->s_gain2);
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floatinlet_new(&x->x_obj, &x->s_ltransfq);
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floatinlet_new(&x->x_obj, &x->s_htransfq);
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outlet_new(&x->x_obj, &s_list);
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return (x);
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}
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void hlshelf_setup(void)
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{
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hlshelf_class = class_new(gensym("hlshelf"), (t_newmethod)hlshelf_new, 0,
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sizeof(t_hlshelf), 0, A_GIMME, 0);
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class_addbang(hlshelf_class,hlshelf_bang);
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class_addfloat(hlshelf_class,hlshelf_float);
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}
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