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Diffstat (limited to 'src/sample_and_hold.c')
| -rw-r--r-- | src/sample_and_hold.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/src/sample_and_hold.c b/src/sample_and_hold.c new file mode 100644 index 0000000..6b0abeb --- /dev/null +++ b/src/sample_and_hold.c @@ -0,0 +1,150 @@ +/* Sample and Hold. + * Copyright 2005 Thorsten Wilms. + * Based on David Robillard's "Hz to AMS style V/Oct" plugin for the skeleton. + * + * This plugin 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 plugin 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 + * 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 <string.h> + +#include <lv2/lv2plug.in/ns/lv2core/lv2.h> + +#define ID 4430 + +#define NUM_PORTS 5 + +/* Port Numbers */ +#define INPUT 0 +#define TRIGGER 1 +#define THRESHOLD 2 +#define CONTINUOUS 3 +#define OUTPUT 4 + +/* All state information for plugin */ +typedef struct +{ + /* Ports */ + float* input_buffer; + float* trigger_buffer; + float* threshold_buffer; + float* continuous_buffer; + float* output_buffer; + + float hold; /* the value sampled and held */ + float last_trigger; /* trigger port value from the previous frame */ +} SH; + +/* Construct a new plugin instance */ +static LV2_Handle +instantiate(const LV2_Descriptor* descriptor, + double sample_rate, + const char* bundle_path, + const LV2_Feature* const* features) +{ + return (LV2_Handle)malloc(sizeof(SH)); +} + +/* Connect a port to a data location */ +static void +connect_port(LV2_Handle instance, + uint32_t port, + void* data) +{ + SH* plugin = (SH*)instance; + + switch (port) { + case INPUT: + plugin->input_buffer = (float*)data; + break; + case TRIGGER: + plugin->trigger_buffer = (float*)data; + break; + case THRESHOLD: + plugin->threshold_buffer = (float*)data; + break; + case CONTINUOUS: + plugin->continuous_buffer = (float*)data; + break; + case OUTPUT: + plugin->output_buffer = (float*)data; + break; + } +} + +static void +activate(LV2_Handle instance) +{ + SH* plugin = (SH*)instance; + + plugin->hold = 0; + plugin->last_trigger = 0; +} + +static void +run(LV2_Handle instance, uint32_t nframes) +{ + SH* const plugin = (SH*)instance; + const float* const input = plugin->input_buffer; + const float* const trigger = plugin->trigger_buffer; + const float* const threshold = plugin->threshold_buffer; + const float* const continuous = plugin->continuous_buffer; + float* const output = plugin->output_buffer; + + unsigned long i; + + for (i = 0; i < nframes; i++) { + if (continuous[0] != 0) { + /* Continuous triggering on (sample while trigger > threshold) */ + if (trigger[i] >= threshold[i]) + plugin->hold = input[i]; + } else { + /* Continuous triggering off + * (only sample on first frame with trigger > threshold) */ + if (plugin->last_trigger < threshold[i] && trigger[i] >= threshold[i]) + plugin->hold = input[i]; + } + + plugin->last_trigger = trigger[i]; + output[i] = plugin->hold; + } +} + +static void +cleanup(LV2_Handle instance) +{ + free(instance); +} + +static const LV2_Descriptor descriptor = { + "http://drobilla.net/plugins/omins/sample_and_hold", + 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; + } +} |