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Diffstat (limited to 'src/adenv.c')
| -rw-r--r-- | src/adenv.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/src/adenv.c b/src/adenv.c new file mode 100644 index 0000000..dabca16 --- /dev/null +++ b/src/adenv.c @@ -0,0 +1,250 @@ +/* + adenv.c - A LV2 plugin to generate percussive (i.e no sustain time), linear AD envelopes. + + Copyright 2005 Loki Davison + based on ADENV by Mike Rawes + + 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 2 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, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA +*/ + +#define _XOPEN_SOURCE 600 /* strdup */ +#include <stdlib.h> +#include <lv2/lv2plug.in/ns/lv2core/lv2.h> +#include <stdio.h> +#include <math.h> + +#define ADENV_BASE_ID 2661 + +#define ADENV_GATE 0 +#define ADENV_TRIGGER 1 +#define ADENV_ATTACK 2 +#define ADENV_DECAY 3 +#define ADENV_OUTPUT 4 + +LV2_Descriptor **dahdsr_descriptors = 0; + +typedef enum { + IDLE, + ATTACK, + DECAY, +} ADENVState; + +typedef struct { + float *gate; + float *trigger; + float *attack; + float *decay; + float *output; + float srate; + float inv_srate; + float last_gate; + float last_trigger; + float from_level; + float level; + ADENVState state; + unsigned long samples; +} Dahdsr; + +static void +cleanup(LV2_Handle instance) +{ + free(instance); +} + +static void +connect_port(LV2_Handle instance, + uint32_t port, + void* data) +{ + Dahdsr *plugin = (Dahdsr *) instance; + + switch (port) { + case ADENV_GATE: + plugin->gate = (float*)data; + break; + case ADENV_TRIGGER: + plugin->trigger = (float*)data; + break; + case ADENV_ATTACK: + plugin->attack = (float*)data; + break; + case ADENV_DECAY: + plugin->decay = (float*)data; + break; + case ADENV_OUTPUT: + plugin->output = (float*)data; + break; + } +} + +static LV2_Handle +instantiate(const LV2_Descriptor* descriptor, + double sample_rate, + const char* bundle_path, + const LV2_Feature* const* features) +{ + Dahdsr *plugin = (Dahdsr *) malloc(sizeof(Dahdsr)); + + plugin->srate = (float) sample_rate; + plugin->inv_srate = 1.0f / plugin->srate; + + return (LV2_Handle) plugin; +} + +static void +activate(LV2_Handle instance) +{ + Dahdsr *plugin = (Dahdsr *) instance; + + plugin->last_gate = 0.0f; + plugin->last_trigger = 0.0f; + plugin->from_level = 0.0f; + plugin->level = 0.0f; + plugin->state = IDLE; + plugin->samples = 0; +} + +static void +run(LV2_Handle instance, uint32_t sample_count) +{ + Dahdsr *plugin = (Dahdsr *) instance; + + /* Gate */ + float *gate = plugin->gate; + + /* Trigger */ + float *trigger = plugin->trigger; + + /* Attack Time (s) */ + float attack = *(plugin->attack); + + /* Decay Time (s) */ + float decay = *(plugin->decay); + + /* Envelope Out */ + float *output = plugin->output; + + /* Instance Data */ + float srate = plugin->srate; + float inv_srate = plugin->inv_srate; + float last_gate = plugin->last_gate; + float last_trigger = plugin->last_trigger; + float from_level = plugin->from_level; + float level = plugin->level; + ADENVState state = plugin->state; + unsigned long samples = plugin->samples; + + float gat, trg, att, dec; + float elapsed; + unsigned long s; + + /* Convert times into rates */ + att = attack > 0.0f ? inv_srate / attack : srate; + dec = decay > 0.0f ? inv_srate / decay : srate; + /* cuse's formula ... + * ReleaseCoeff = (ln(EndLevel) - ln(StartLevel)) / (EnvelopeDuration * SampleRate) + * + * while (currentSample < endSample) Level += Level * ReleaseCoeff; + */ + + float ReleaseCoeff = log(0.001) / (decay * srate); + + for (s = 0; s < sample_count; s++) { + gat = gate[s]; + trg = trigger[s]; + + /* Initialise delay phase if gate is opened and was closed, or + we received a trigger */ + if ((trg > 0.0f && !(last_trigger > 0.0f)) || + (gat > 0.0f && !(last_gate > 0.0f))) { + //fprintf(stderr, "triggered in control \n"); + if (att <= srate) { + state = ATTACK; + } + samples = 0; + } + + if (samples == 0) + from_level = level; + + /* Calculate level of envelope from current state */ + switch (state) { + case IDLE: + level = 0; + break; + case ATTACK: + samples++; + elapsed = (float) samples *att; + + if (elapsed > 1.0f) { + state = DECAY; + level = 1.0f; + samples = 0; + } else { + level = from_level + elapsed * (1.0f - from_level); + } + break; + case DECAY: + samples++; + elapsed = (float) samples *dec; + + if (elapsed > 1.0f) { + state = IDLE; + level = 0.0f; + samples = 0; + } else { + //fprintf(stderr, "decay, dec %f elapsed %f from level %f level %f\n", dec, elapsed, from_level, level); + level += level * ReleaseCoeff; + + } + break; + default: + /* Should never happen */ + fprintf(stderr, "bugger!!!"); + level = 0.0f; + } + + output[s] = level; + last_gate = gat; + last_trigger = trg; + } + + plugin->last_gate = last_gate; + plugin->last_trigger = last_trigger; + plugin->from_level = from_level; + plugin->level = level; + plugin->state = state; + plugin->samples = samples; +} + +static const LV2_Descriptor descriptor = { + "http://drobilla.net/plugins/omins/adenv", + instantiate, + connect_port, + activate, + run, + NULL, + cleanup, + NULL, +}; + +LV2_SYMBOL_EXPORT const LV2_Descriptor* +lv2_descriptor(uint32_t index) +{ + switch (index) { + case 0: return &descriptor; + default: return NULL; + } +} |