Sampled Instrument Player with static and monolithic design. All instruments are built-in.
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/*
Calf Box, an open source musical instrument.
Copyright (C) 2010 Krzysztof Foltman
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef CBOX_ONEPOLE_INT_H
#define CBOX_ONEPOLE_INT_H
#include "dspmath.h"
struct cbox_onepole_state
{
int32_t x1;
int32_t y1;
};
struct cbox_onepole_coeffs
{
int32_t a0;
int32_t a1;
int32_t b1;
int shift;
};
static inline void cbox_onepole_reset(struct cbox_onepole_state *state)
{
state->x1 = state->y1 = 0;
}
static inline void cbox_onepole_set_lowpass(struct cbox_onepole_coeffs *coeffs, float w)
{
float x = tan (w);
float q = 1 / (1 + x);
float a01 = x*q;
float b1 = a01 - q;
int shift = 28;
float scaler = (1 << shift);
coeffs->a1 = coeffs->a0 = (int32_t)(a01 * scaler);
coeffs->b1 = (int32_t)(b1 * scaler);
coeffs->shift = shift;
}
static inline void cbox_onepole_set_highpass(struct cbox_onepole_coeffs *coeffs, float w)
{
float x = tan (w);
float q = 1 / (1 + x);
float a01 = x*q;
float b1 = a01 - q;
int shift = 28;
float scaler = (1 << shift)-1;
coeffs->a0 = (int32_t)(a01 * scaler);
coeffs->a1 = -coeffs->a0;
coeffs->b1 = (int32_t)(b1 * scaler);
coeffs->shift = shift;
}
static inline void cbox_onepole_process(struct cbox_onepole_state *state, struct cbox_onepole_coeffs *coeffs, int32_t *buffer)
{
int i;
int64_t a0 = coeffs->a0;
int64_t a1 = coeffs->a1;
int64_t b1 = coeffs->b1;
int shift = coeffs->shift;
int64_t maxint = ((int64_t)0x7FFFFFF) << shift;
int32_t round = 1 << (shift - 1);
for (i = 0; i < CBOX_BLOCK_SIZE; i++)
{
int32_t in = buffer[i];
int64_t v = a0 * in + a1 * state->x1 - b1 * state->y1 + round;
int32_t out = (llabs(v) >= maxint) ? (v > 0 ? 0x7FFFFFFF : -0x7FFFFFFF) : (v >> shift);
buffer[i] = out;
state->x1 = in;
state->y1 = out;
}
if (state->y1 > 0 && state->y1 < round)
state->y1--;
if (state->y1 < 0 && state->y1 > -round)
state->y1++;
}
static inline void cbox_onepole_process_to(struct cbox_onepole_state *state, struct cbox_onepole_coeffs *coeffs, int32_t *buffer_in, int32_t *buffer_out)
{
int i;
int64_t a0 = coeffs->a0;
int64_t a1 = coeffs->a1;
int64_t b1 = coeffs->b1;
int shift = coeffs->shift;
int64_t maxint = ((int64_t)0x7FFFFFF) << shift;
int64_t round = 1 << (shift - 1);
for (i = 0; i < CBOX_BLOCK_SIZE; i++)
{
int32_t in = buffer_in[i];
int64_t v = a0 * in + a1 * state->x1 - b1 * state->y1 + round;
int32_t out = (llabs(v) >= maxint) ? (v > 0 ? 0x7FFFFFFF : -0x7FFFFFFF) : (v >> shift);
buffer_out[i] = out;
state->x1 = in;
state->y1 = out;
}
}
#endif