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Diffstat (limited to 'src/slide.c')
| -rw-r--r-- | src/slide.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/slide.c b/src/slide.c new file mode 100644 index 0000000..fe026f7 --- /dev/null +++ b/src/slide.c @@ -0,0 +1,170 @@ +/* slide.c - A LV2 plugin that "slides" the output signal between + * the current and the previous input value, taking the given + * number of seconds to reach the current input value. + * + * Copyright 2005 Lars Luthman + * LV2 skeleton code taken from dahdsr_fexp.c by Loki Davison + * + * 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 <lv2/lv2plug.in/ns/lv2core/lv2.h> +#include <math.h> + +/* These are the port numbers */ +#define SLIDE_INPUT 0 +#define SLIDE_RISETIME 1 +#define SLIDE_FALLTIME 2 +#define SLIDE_OUTPUT 3 + +/* This is the data for a single instance of the plugin */ +typedef struct +{ + float* input; + float* risetime; + float* falltime; + float* output; + float srate; + float from; + float to; + float last_output; +} Slide; + +/* Clean up after a plugin instance */ +static void cleanup (LV2_Handle instance) +{ + free(instance); +} + +/* This is called when the hosts connects a port to a buffer */ +static void connect_port(LV2_Handle instance, + uint32_t port, void* data) +{ + Slide* plugin = (Slide *)instance; + + switch (port) { + case SLIDE_INPUT: + plugin->input = (float*)data; + break; + case SLIDE_RISETIME: + plugin->risetime = (float*)data; + break; + case SLIDE_FALLTIME: + plugin->falltime = (float*)data; + break; + case SLIDE_OUTPUT: + plugin->output = (float*)data; + break; + } +} + +/* The host uses this function to create an instance of a plugin */ +static LV2_Handle +instantiate(const LV2_Descriptor* descriptor, + double sample_rate, + const char* bundle_path, + const LV2_Feature* const* features) +{ + Slide* plugin = (Slide*)calloc(1, sizeof(Slide)); + plugin->srate = (float)sample_rate; + return (LV2_Handle)plugin; +} + +/* This is called before the hosts starts to use the plugin instance */ +static void activate(LV2_Handle instance) +{ + Slide* plugin = (Slide*)instance; + plugin->last_output = 0; + plugin->from = 0; + plugin->to = 0; +} + +/* The run function! */ +static void run(LV2_Handle instance, uint32_t sample_count) +{ + Slide* plugin = (Slide*)instance; + + if (plugin->input && plugin->output) { + unsigned long i; + float risetime, falltime; + for (i = 0; i < sample_count; ++i) { + + if (plugin->risetime) + risetime = plugin->risetime[i]; + else + risetime = 0; + + if (plugin->falltime) + falltime = plugin->falltime[i]; + else + falltime = 0; + + /* If the signal changed, start sliding to the new value */ + if (plugin->input[i] != plugin->to) { + plugin->from = plugin->last_output; + plugin->to = plugin->input[i]; + } + + float time; + int rising; + if (plugin->to > plugin->from) { + time = risetime; + rising = 1; + } else { + time = falltime; + rising = 0; + } + + /* If the rise/fall time is 0, just copy the input to the output */ + if (time == 0) + plugin->output[i] = plugin->input[i]; + + /* Otherwise, do the portamento */ + else { + float increment = + (plugin->to - plugin->from) / (time * plugin->srate); + plugin->output[i] = plugin->last_output + increment; + if ((plugin->output[i] > plugin->to && rising) || + (plugin->output[i] < plugin->to && !rising)) { + plugin->output[i] = plugin->to; + } + } + + plugin->last_output = plugin->output[i]; + } + } +} + +static const LV2_Descriptor descriptor = { + "http://drobilla.net/plugins/omins/slide", + 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; + } +} |