Max 5 API Reference

jit.transfer.gain.c

/*
 *  jit.transfer.gain.c
 *
 *  Copyright 2001-2005 - Cycling '74
 *  Derek Gerstmann - derek@cycling74.com
 *
 *  functor for perlin's "gain" transfer function
 *
 */

// --------------------------------------------------------------------------

#include "jit.common.h"
#include "jit.functor.h"

// --------------------------------------------------------------------------

typedef struct _jit_functor_transfer_gain
{
    t_jit_object    ob;
    double          beta;   // 0.5 is no change, smaller values bias towards 0, larger towards 1.
    double          invbeta;
} t_jit_functor_transfer_gain;

// --------------------------------------------------------------------------

t_jit_object *jit_functor_transfer_gain_new(void);
t_jit_err jit_functor_transfer_gain_free(t_jit_functor_transfer_gain *x);
t_jit_err jit_functor_transfer_gain_setattr_beta(t_jit_functor_transfer_gain *x, void *attr, long argc, t_atom *argv);
t_jit_err jit_functor_transfer_gain_recalc(t_jit_functor_transfer_gain *x);

long jit_functor_transfer_gain_eval_fixed(t_jit_functor_transfer_gain *x, long dimcount, long *vals);
float jit_functor_transfer_gain_eval_float32(t_jit_functor_transfer_gain *x, long dimcount, float *vals);
double jit_functor_transfer_gain_eval_float64(t_jit_functor_transfer_gain *x, long dimcount, double *vals);
long jit_functor_transfer_gain_eval_fixed_scalar(t_jit_functor_transfer_gain *x, long val);
float jit_functor_transfer_gain_eval_float32_scalar(t_jit_functor_transfer_gain *x, float val);
double jit_functor_transfer_gain_eval_float64_scalar(t_jit_functor_transfer_gain *x, double val);

t_class * _jit_functor_transfer_gain_class;

// --------------------------------------------------------------------------

t_jit_err jit_functor_transfer_gain_init(void)
{
    t_jit_object *attr;

    // create functor class
    _jit_functor_transfer_gain_class = jit_class_new("jit_functor_transfer_gain",
        (method)jit_functor_transfer_gain_new,(method)jit_functor_transfer_gain_free,
        sizeof(t_jit_functor_transfer_gain),0L);

    // add attribute methods
    attr = jit_object_new(_jit_sym_jit_attr_offset,"beta",_jit_sym_float64,0,
        (method)0L,(method)jit_functor_transfer_gain_setattr_beta,
        calcoffset(t_jit_functor_transfer_gain,beta));
    jit_class_addattr(_jit_functor_transfer_gain_class,attr);

    // add evaluation methods
    jit_class_addmethod(_jit_functor_transfer_gain_class, 
        (method)jit_functor_transfer_gain_eval_fixed,   "evalfixed", A_CANT, 0L);
    jit_class_addmethod(_jit_functor_transfer_gain_class, 
        (method)jit_functor_transfer_gain_eval_float32, "evalfloat32", A_CANT, 0L);
    jit_class_addmethod(_jit_functor_transfer_gain_class, 
        (method)jit_functor_transfer_gain_eval_float64, "evalfloat64", A_CANT, 0L);

    // important to add last for subclassing methods
    jit_functor_setup_class(_jit_functor_transfer_gain_class,"transfer","gain");
    jit_class_register(_jit_functor_transfer_gain_class);

    return JIT_ERR_NONE;
}

t_jit_object *jit_functor_transfer_gain_new(void)
{
    t_jit_functor_transfer_gain *x;

    if (x = (t_jit_functor_transfer_gain *)jit_object_alloc(_jit_functor_transfer_gain_class)) {

        // initialization
        x->beta = 0.5;
        jit_functor_transfer_gain_recalc(x);
    }

    return (t_jit_object *)x;
}

t_jit_err jit_functor_transfer_gain_free(t_jit_functor_transfer_gain *x)
{
    return JIT_ERR_NONE;
}

t_jit_err jit_functor_transfer_gain_setattr_beta(
    t_jit_functor_transfer_gain *x, void *attr, long argc, t_atom *argv)
{
    double v;

    if (x) {
        v = jit_atom_getfloat(argv);
        if (x->beta != v) {
            x->beta = v;
            jit_functor_transfer_gain_recalc(x);
        }
        return JIT_ERR_NONE;
    }
    return JIT_ERR_INVALID_PTR;
}

t_jit_err jit_functor_transfer_gain_recalc(t_jit_functor_transfer_gain *x)
{
    // calculate intermediary values for efficiency
    x->invbeta = ( 1.0 / x->beta - 2.0);
    return JIT_ERR_NONE;
}

// --------------------------------------------------------------------------
// vector evaluation functions (calls scalar functions and generates a product of scalar evaluation for each dimension)
// --------------------------------------------------------------------------
long jit_functor_transfer_gain_eval_fixed(t_jit_functor_transfer_gain *x, long dimcount, long *vals)
{
    return jit_functor_eval_fixed_with_float64((t_jit_object *)x,dimcount,vals,
            (t_jit_functor_float64_sig)jit_functor_transfer_gain_eval_float64);
}

float jit_functor_transfer_gain_eval_float32(t_jit_functor_transfer_gain *x, long dimcount, float *vals)
{
    return jit_functor_eval_float32_with_scalar_product((t_jit_object *)x,dimcount,vals,
            (t_jit_functor_float32_scalar_sig)jit_functor_transfer_gain_eval_float32_scalar);
}

double jit_functor_transfer_gain_eval_float64(t_jit_functor_transfer_gain *x, long dimcount, double *vals)
{
    return jit_functor_eval_float64_with_scalar_product((t_jit_object *)x,dimcount,vals,
            (t_jit_functor_float64_scalar_sig)jit_functor_transfer_gain_eval_float64_scalar);
}

// --------------------------------------------------------------------------
// scalar evaluation functions
// --------------------------------------------------------------------------
long jit_functor_transfer_gain_eval_fixed_scalar(
    t_jit_functor_transfer_gain *x, long val)
{
    return FloatToFixed(jit_functor_transfer_gain_eval_float64_scalar(x,FixedToFloat(val)));
}

float jit_functor_transfer_gain_eval_float32_scalar(
    t_jit_functor_transfer_gain *x, float val)
{
/*
    float a = val;
    float p = (float)jit_math_log(1.0f - x->beta) / (float)jit_math_log(0.5f);
    if (a < .001f)
        return 0.0f;
    else if (a > .999f)
        return 1.0f;
    if (a < 0.5f)
        return (float)jit_math_pow(2 * a, p) / 2;
    else
        return 1.0f - (float)jit_math_pow(2 * (1. - a), p) / 2;
*/
    // fast approximate to above
    float a = val;
    float c = x->invbeta * (1.0f - 2.0f * a);
    if (a < 0.5f)
        return a / ( c + 1.0f );
    else
        return (c - a) / (c - 1.0f );
}

double jit_functor_transfer_gain_eval_float64_scalar(
    t_jit_functor_transfer_gain *x, double val)
{

/*
    double a = val;
    double p = jit_math_log(1.0 - x->beta) / jit_math_log(0.5);
    if (a < .001)
        return 0.0;
    else if (a > .999)
        return 1.0;
    if (a < 0.5)
        return jit_math_pow(2 * a, p) / 2;
    else
        return 1.0 - jit_math_pow(2 * (1. - a), p) / 2;
*/
    // fast approximate to above
    float a = val;
    float c = x->invbeta * (1.0 - 2.0 * a);
    if (a < 0.5)
        return a / ( c + 1.0);
    else
        return (c - a) / (c - 1.0);
}
// --------------------------------------------------------------------------

Copyright © 2008, Cycling '74