modulator[] mod; /* sinus/triangle modulator */
/*-----------------------------------------------------------------------------
* API
* ------------------------------------------------------------------------------*/
/**
* Create the chorus unit.
* @sample_rate audio sample rate in Hz.
* @return pointer on chorus unit.
*/
public fluid_chorus(float psample_rate, int bufsize)
{
FLUID_BUFSIZE = bufsize;
sample_rate = psample_rate;
mod = new modulator[MAX_CHORUS];
for (int i = 0; i < MAX_CHORUS; i++)
{
mod[i] = new modulator();
}
//# ifdef DEBUG_PRINT
// printf("fluid_chorus_t:{0} bytes\n", sizeof(fluid_chorus_t));
// printf("float:{0} bytes\n", sizeof(float));
//#endif
//# ifdef DEBUG_PRINT
// printf("NEW_MOD\n");
//#endif
new_mod_delay_line(MAX_SAMPLES);
}
/*-----------------------------------------------------------------------------
* Reads the sample value out of the modulated delay line.
* @param mdl, pointer on modulated delay line.
* @return the sample value.
* -----------------------------------------------------------------------------*/
float get_mod_delay(modulator mod)
{
float out_index; /* new modulated index position */
int int_out_index; /* integer part of out_index */
float outp; /* value to return */
/* Checks if the modulator must be updated (every mod_rate samples). */
/* Important: center_pos_mod must be used immediately for the
* first sample. So, mdl.index_rate must be initialized
* to mdl.mod_rate (new_mod_delay_line()) */
if (index_rate >= mod_rate)
{
/* out_index = center position (center_pos_mod) + sinus waweform */
if (type == fluid_chorus_mod.FLUID_CHORUS_MOD_SINE)
{
out_index = center_pos_mod + get_mod_sinus(mod.sinus) * mod_depth;
}
else
{
out_index = center_pos_mod + get_mod_triang(mod.triang) * mod_depth;
}
/* extracts integer part in int_out_index */
if (out_index >= 0f)
{
int_out_index = (int)out_index; /* current integer part */
/* forces read index (line_out) with integer modulation value */
/* Boundary check and circular motion as needed */
if ((mod.line_out = int_out_index) >= size)
{
mod.line_out -= size;
}
}
else /* negative */
{
int_out_index = (int)(out_index - 1); /* previous integer part */
/* forces read index (line_out) with integer modulation value */
/* circular motion as needed */
mod.line_out = int_out_index + size;
}
/* extracts fractionnal part. (it will be used when interpolating
* between line_out and line_out +1) and memorize it.
* Memorizing is necessary for modulation rate above 1 */
mod.frac_pos_mod = out_index - int_out_index;
}
/* First order all-pass interpolation ----------------------------------*/
/* https://ccrma.stanford.edu/~jos/pasp/First_Order_Allpass_Interpolation.html */
/* begins interpolation: read current sample */
outp = line[mod.line_out];
/* updates line_out to the next sample.
* Boundary check and circular motion as needed */
if (++mod.line_out >= size)
{
mod.line_out -= size;
}
/* Fractional interpolation between next sample (at next position) and
* previous output added to current sample.
*/
outp += mod.frac_pos_mod * (line[mod.line_out] - mod.buffer);
mod.buffer = outp; /* memorizes current output */
return(outp);
}
