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Diffstat (limited to 'src/triangle.c')
| -rw-r--r-- | src/triangle.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/src/triangle.c b/src/triangle.c new file mode 100644 index 0000000..09c01c2 --- /dev/null +++ b/src/triangle.c @@ -0,0 +1,232 @@ +/* + An LV2 plugin to generate a bandlimited slope-variable triangle waveform. + Copyright 2011 David Robillard + Copyright 2002 Mike Rawes + + This 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 software 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 software. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include <stdlib.h> +#include "lv2/lv2plug.in/ns/ext/morph/morph.h" +#include "lv2/lv2plug.in/ns/ext/options/options.h" +#include "lv2/lv2plug.in/ns/lv2core/lv2.h" +#include "uris.h" +#include "wavedata.h" + +#define TRIANGLE_FREQUENCY 0 +#define TRIANGLE_SLOPE 1 +#define TRIANGLE_OUTPUT 2 + +typedef struct { + const float* frequency; + const float* slope; + float* output; + float phase; + float min_slope; + float max_slope; + uint32_t frequency_is_cv; + uint32_t slope_is_cv; + Wavedata wdat; + URIs uris; +} Triangle; + +static void +connect_port(LV2_Handle instance, + uint32_t port, + void* data) +{ + Triangle* plugin = (Triangle*)instance; + + switch (port) { + case TRIANGLE_FREQUENCY: + plugin->frequency = (const float*)data; + break; + case TRIANGLE_SLOPE: + plugin->slope = (const float*)data; + break; + case TRIANGLE_OUTPUT: + plugin->output = (float*)data; + break; + } +} + +static uint32_t +options_set(LV2_Handle instance, + const LV2_Options_Option* options) +{ + Triangle* plugin = (Triangle*)instance; + uint32_t ret = 0; + for (const LV2_Options_Option* o = options; o->key; ++o) { + if (o->context != LV2_OPTIONS_PORT) { + ret |= LV2_OPTIONS_ERR_BAD_SUBJECT; + } else if (o->key != plugin->uris.morph_currentType) { + ret |= LV2_OPTIONS_ERR_BAD_KEY; + } else if (o->type != plugin->uris.atom_URID) { + ret |= LV2_OPTIONS_ERR_BAD_VALUE; + } else { + LV2_URID port_type = *(const LV2_URID*)(o->value); + if (port_type != plugin->uris.lv2_ControlPort && + port_type != plugin->uris.lv2_CVPort) { + ret |= LV2_OPTIONS_ERR_BAD_VALUE; + continue; + } + + switch (o->subject) { + case TRIANGLE_FREQUENCY: + plugin->frequency_is_cv = (port_type == plugin->uris.lv2_CVPort); + break; + case TRIANGLE_SLOPE: + plugin->slope_is_cv = (port_type == plugin->uris.lv2_CVPort); + break; + default: + ret |= LV2_OPTIONS_ERR_BAD_SUBJECT; + } + } + } + return ret; +} + +static LV2_Handle +instantiate(const LV2_Descriptor* descriptor, + double sample_rate, + const char* bundle_path, + const LV2_Feature* const* features) +{ + Triangle* plugin = (Triangle*)malloc(sizeof(Triangle)); + if (!plugin) { + return NULL; + } + + if (wavedata_load(&plugin->wdat, bundle_path, "parabola_data", + BLOP_DLSYM_PARABOLA, sample_rate)) { + free(plugin); + return 0; + } + + plugin->min_slope = 2.0f / plugin->wdat.sample_rate; + plugin->max_slope = 1.0f - plugin->min_slope; + + plugin->frequency_is_cv = 0; + plugin->slope_is_cv = 0; + + map_uris(&plugin->uris, features); + wavedata_get_table(&plugin->wdat, 440.0); + + return (LV2_Handle)plugin; +} + +static void +cleanup(LV2_Handle instance) +{ + Triangle* plugin = (Triangle*)instance; + + wavedata_unload(&plugin->wdat); + free(instance); +} + +static void +activate(LV2_Handle instance) +{ + Triangle* plugin = (Triangle*)instance; + + plugin->phase = 0.0f; +} + +static void +run(LV2_Handle instance, + uint32_t sample_count) +{ + Triangle* plugin = (Triangle*)instance; + + /* Frequency (array of float of length 1 or sample_count) */ + const float* frequency = plugin->frequency; + + /* Slope (array of float of length 1 or sample_count) */ + const float* slope = plugin->slope; + + /* Output (pointer to float value) */ + float* output = plugin->output; + + /* Instance data */ + Wavedata* wdat = &plugin->wdat; + float phase = plugin->phase; + const float min_slope = plugin->min_slope; + const float max_slope = plugin->max_slope; + + float last_slope = slope[0]; + float slp = f_clip(last_slope, min_slope, max_slope); + float phase_shift = slp * wdat->sample_rate; + float scale = 1.0f / (8.0f * (slp - (slp * slp))); + + for (uint32_t s = 0; s < sample_count; ++s) { + const float freq = frequency[s * plugin->frequency_is_cv]; + if (freq != wdat->frequency) { + /* Frequency changed, look up table to play */ + wavedata_get_table(wdat, freq); + } + + const float this_slope = slope[s * plugin->slope_is_cv]; + if (this_slope != last_slope) { + /* Slope changed, recalculate */ + last_slope = this_slope; + slp = f_clip(this_slope, min_slope, max_slope); + phase_shift = slp * wdat->sample_rate; + scale = 1.0f / (8.0f * (slp - (slp * slp))); + } + + /* Get samples from parabola and phase shifted inverted parabola, + and scale to compensate */ + output[s] = (wavedata_get_sample(wdat, phase) + - wavedata_get_sample(wdat, phase + phase_shift)) * scale; + + /* Update phase, wrapping if necessary */ + phase += wdat->frequency; + if (phase < 0.0f) { + phase += wdat->sample_rate; + } else if (phase > wdat->sample_rate) { + phase -= wdat->sample_rate; + } + } + plugin->phase = phase; +} + +static const void* +extension_data(const char* uri) +{ + static const LV2_Options_Interface options = { NULL, options_set }; + if (!strcmp(uri, LV2_OPTIONS__interface)) { + return &options; + } + return NULL; +} + +static const LV2_Descriptor descriptor = { + "http://drobilla.net/plugins/blop/triangle", + instantiate, + connect_port, + activate, + run, + NULL, + cleanup, + extension_data, +}; + +LV2_SYMBOL_EXPORT const LV2_Descriptor* +lv2_descriptor(uint32_t index) +{ + switch (index) { + case 0: return &descriptor; + default: return NULL; + } +} |