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/* abGate - LV2 Noise Gate Plugin
*
* Copyright 2011 Antanas Bružas
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdlib.h>
#include <lv2.h>
#include <cmath>
#include "gate_const.h"
#define CLOSED 1
#define ATTACK 2
#define OPENED 3
#define DECAY 4
static LV2_Descriptor *gateDescriptor = NULL;
class Gate {
public:
Gate() {
state = CLOSED;
gate = 0;
holding = 0;
}
~Gate() {
}
float *switch_button, *threshold, *attack, *hold, *decay, *range, sample_rate, gate, *output;
const float *input;
int state, holding;
};
static LV2_Handle instantiateGate(const _LV2_Descriptor *descriptor, double s_rate, const char *path, const LV2_Feature * const * features) {
Gate *plugin_data = new Gate;
plugin_data->sample_rate = s_rate;
return (LV2_Handle) plugin_data;
}
static void connectPortGate(LV2_Handle instance, uint32_t port, void *data) {
Gate *plugin = (Gate *) instance;
switch (port) {
case p_switch:
plugin->switch_button = (float*) data;
break;
case p_threshold:
plugin->threshold = (float*) data;
break;
case p_attack:
plugin->attack = (float*) data;
break;
case p_hold:
plugin->hold = (float*) data;
break;
case p_decay:
plugin->decay = (float*) data;
break;
case p_gaterange:
plugin->range = (float*) data;
break;
case p_input:
plugin->input = (const float*) data;
break;
case p_output:
plugin->output = (float*) data;
break;
}
}
static void runGate(LV2_Handle instance, uint32_t sample_count) {
Gate *plugin_data = (Gate *) instance;
float * const output = plugin_data->output;
const float * const input = plugin_data->input;
// Checking bypass state
float switch_button = *(plugin_data->switch_button);
switch_button = switch_button < 0 ? 0 : switch_button;
switch_button = switch_button > 1 ? 1 : switch_button;
bool active = switch_button > 0;
if (active) {
// Getting port values
const float threshold = *(plugin_data->threshold);
const float attack = *(plugin_data->attack);
const float hold = *(plugin_data->hold);
const float decay = *(plugin_data->decay);
const float range = *(plugin_data->range);
const float sample_rate = plugin_data->sample_rate;
const float threshold_value = pow(10, threshold * 0.05);
const float attack_coef = 1000 / (attack * sample_rate);
const int hold_samples = round(hold * sample_rate * 0.001);
const float decay_coef = 1000 / (decay * sample_rate);
const float range_coef = range > -90 ? pow(10, range * 0.05) : 0;
int state = plugin_data->state;
float gate = plugin_data->gate;
int holding = plugin_data->holding;
for (uint32_t i = 0; i < sample_count; ++i) {
// Counting input dB
float sample = input[i];
float abs_sample = fabs(sample);
switch (state) {
case CLOSED:
case DECAY:
if (abs_sample >= threshold_value) {
state = ATTACK;
}
break;
case ATTACK:
break;
case OPENED:
if (abs_sample >= threshold_value) {
holding = hold_samples;
} else if (holding <= 0) {
state = DECAY;
} else {
holding--;
}
break;
default:
// shouldn't happen
state = CLOSED;
}
// handle attack/decay in a second pass to avoid unnecessary one-sample delay
switch (state) {
case CLOSED:
output[i] = sample * range_coef;
break;
case DECAY:
gate -= decay_coef;
if (gate <= 0) {
gate = 0;
state = CLOSED;
}
output[i] = sample * (range_coef * (1 - gate) + gate);
break;
case ATTACK:
gate += attack_coef;
if (gate >= 1) {
gate = 1;
state = OPENED;
holding = hold_samples;
}
output[i] = sample * (range_coef * (1 - gate) + gate);
break;
case OPENED:
output[i] = sample;
break;
}
}
plugin_data->gate = gate;
plugin_data->state = state;
plugin_data->holding = holding;
} else {
// Bypassing
if (output != input) {
for (uint32_t i = 0; i < sample_count; ++i) {
output[i] = input[i];
}
}
}
}
static void cleanupGate(LV2_Handle instance) {
Gate *plugin_data = (Gate *) instance;
delete plugin_data;
}
static void init() {
gateDescriptor = (LV2_Descriptor *) malloc(sizeof(LV2_Descriptor));
gateDescriptor->URI = p_uri;
gateDescriptor->instantiate = instantiateGate;
gateDescriptor->connect_port = connectPortGate;
gateDescriptor->activate = NULL;
gateDescriptor->run = runGate;
gateDescriptor->deactivate = NULL;
gateDescriptor->cleanup = cleanupGate;
gateDescriptor->extension_data = NULL;
}
LV2_SYMBOL_EXPORT
const LV2_Descriptor *lv2_descriptor(uint32_t index) {
if (!gateDescriptor) {
init();
}
switch (index) {
case 0:
return gateDescriptor;
default:
return NULL;
}
}
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