From 741586ae2aa4f928296a2b4c2dc03830ffaff833 Mon Sep 17 00:00:00 2001 From: David Robillard Date: Wed, 5 Oct 2016 05:31:53 -0400 Subject: Write output between events with sample accuracy This is closer to how a non-toy plugin should work, and importantly demonstrates the proper way to emit audio while processing events. In particular, this approach makes sample-accurate session export possible (thanks to the sychronous possibilities of the worker). --- plugins/eg-sampler.lv2/sampler.c | 232 ++++++++++++++++++++----------------- plugins/eg-sampler.lv2/sampler.ttl | 3 +- 2 files changed, 130 insertions(+), 105 deletions(-) (limited to 'plugins') diff --git a/plugins/eg-sampler.lv2/sampler.c b/plugins/eg-sampler.lv2/sampler.c index 627ba45..9f27737 100644 --- a/plugins/eg-sampler.lv2/sampler.c +++ b/plugins/eg-sampler.lv2/sampler.c @@ -283,6 +283,8 @@ instantiate(const LV2_Descriptor* descriptor, lv2_atom_forge_init(&self->forge, self->map); peaks_sender_init(&self->psend, self->map); + self->gain = 1.0; + return (LV2_Handle)self; } @@ -309,16 +311,119 @@ deactivate(LV2_Handle instance) /** Define a macro for converting a gain in dB to a coefficient. */ #define DB_CO(g) ((g) > -90.0f ? powf(10.0f, (g) * 0.05f) : 0.0f) +/** + Handle an incoming event in the audio thread. + + This performs any actions triggered by an event, such as the start of sample + playback, a sample change, or responding to requests from the UI. +*/ +static void +handle_event(Sampler* self, LV2_Atom_Event* ev) +{ + SamplerURIs* uris = &self->uris; + PeaksURIs* peaks_uris = &self->psend.uris; + + if (ev->body.type == uris->midi_Event) { + const uint8_t* const msg = (const uint8_t*)(ev + 1); + switch (lv2_midi_message_type(msg)) { + case LV2_MIDI_MSG_NOTE_ON: + self->frame = 0; + self->play = true; + break; + default: + break; + } + } else if (lv2_atom_forge_is_object_type(&self->forge, ev->body.type)) { + const LV2_Atom_Object* obj = (const LV2_Atom_Object*)&ev->body; + if (obj->body.otype == uris->patch_Set) { + // Get the property and value of the set message + const LV2_Atom* property = NULL; + const LV2_Atom* value = NULL; + lv2_atom_object_get(obj, + uris->patch_property, &property, + uris->patch_value, &value, + 0); + if (!property) { + lv2_log_error(&self->logger, "Set message with no property\n"); + return; + } else if (property->type != uris->atom_URID) { + lv2_log_error(&self->logger, "Set property is not a URID\n"); + return; + } + + const uint32_t key = ((const LV2_Atom_URID*)property)->body; + if (key == uris->eg_sample) { + // Sample change, send it to the worker. + lv2_log_trace(&self->logger, "Scheduling sample change\n"); + self->schedule->schedule_work(self->schedule->handle, + lv2_atom_total_size(&ev->body), + &ev->body); + } else if (key == uris->param_gain) { + // Gain change + if (value->type == uris->atom_Float) { + self->gain = DB_CO(((LV2_Atom_Float*)value)->body); + } + } + } else if (obj->body.otype == uris->patch_Get) { + const LV2_Atom_URID* accept = NULL; + const LV2_Atom_Int* n_peaks = NULL; + lv2_atom_object_get_typed( + obj, + uris->patch_accept, &accept, uris->atom_URID, + peaks_uris->peaks_total, &n_peaks, peaks_uris->atom_Int, 0); + if (accept && accept->body == peaks_uris->peaks_PeakUpdate) { + // Received a request for peaks, prepare for transmission + peaks_sender_start(&self->psend, + self->sample->data, + self->sample->info.frames, + n_peaks->body); + } else { + // Received a get message, emit our state (probably to UI) + lv2_atom_forge_frame_time(&self->forge, self->frame_offset); + write_set_file(&self->forge, &self->uris, + self->sample->path, + self->sample->path_len); + } + } else { + lv2_log_trace(&self->logger, + "Unknown object type %d\n", obj->body.otype); + } + } else { + lv2_log_trace(&self->logger, + "Unknown event type %d\n", ev->body.type); + } + +} + +/** + Output audio for a slice of the current cycle. +*/ +static void +render(Sampler* self, uint32_t start, uint32_t end) +{ + float* output = self->output_port; + + if (self->play) { + // Start/continue writing sample to output + for (; start < end; ++start) { + output[start] = self->sample->data[self->frame] * self->gain; + if (++self->frame == self->sample->info.frames) { + self->play = false; // Reached end of sample + break; + } + } + } + + // Write silence to remaining buffer + for (; start < end; ++start) { + output[start] = 0.0f; + } +} + static void -run(LV2_Handle instance, - uint32_t sample_count) +run(LV2_Handle instance, uint32_t sample_count) { - Sampler* self = (Sampler*)instance; - SamplerURIs* uris = &self->uris; - PeaksURIs* peaks_uris = &self->psend.uris; - sf_count_t start_frame = 0; - sf_count_t pos = 0; - float* output = self->output_port; + Sampler* self = (Sampler*)instance; // Set up forge to write directly to notify output port. const uint32_t notify_capacity = self->notify_port->atom.size; @@ -338,109 +443,28 @@ run(LV2_Handle instance, self->sample_changed = false; } - // Read incoming events + // Iterate over incoming events, emitting audio along the way + self->frame_offset = 0; LV2_ATOM_SEQUENCE_FOREACH(self->control_port, ev) { + // Render output up to the time of this event + render(self, self->frame_offset, ev->time.frames); + + /* Update current frame offset to this event's time. This is stored in + the instance because it is used for sychronous worker event + execution. This allows a sample load event to be executed with + sample accuracy when running in a non-realtime context (such as + exporting a session). */ self->frame_offset = ev->time.frames; - if (ev->body.type == uris->midi_Event) { - const uint8_t* const msg = (const uint8_t*)(ev + 1); - switch (lv2_midi_message_type(msg)) { - case LV2_MIDI_MSG_NOTE_ON: - start_frame = ev->time.frames; - self->frame = 0; - self->play = true; - break; - default: - break; - } - } else if (lv2_atom_forge_is_object_type(&self->forge, ev->body.type)) { - const LV2_Atom_Object* obj = (const LV2_Atom_Object*)&ev->body; - if (obj->body.otype == uris->patch_Set) { - // Get the property and value of the set message - const LV2_Atom* property = NULL; - const LV2_Atom* value = NULL; - lv2_atom_object_get(obj, - uris->patch_property, &property, - uris->patch_value, &value, - 0); - if (!property) { - lv2_log_error(&self->logger, - "patch:Set message with no property\n"); - continue; - } else if (property->type != uris->atom_URID) { - lv2_log_error(&self->logger, - "patch:Set property is not a URID\n"); - continue; - } - const uint32_t key = ((const LV2_Atom_URID*)property)->body; - if (key == uris->eg_sample) { - // Sample change, send it to the worker. - lv2_log_trace(&self->logger, "Scheduling sample change\n"); - self->schedule->schedule_work(self->schedule->handle, - lv2_atom_total_size(&ev->body), - &ev->body); - } else if (key == uris->param_gain) { - // Gain change - if (value->type == uris->atom_Float) { - self->gain = DB_CO(((LV2_Atom_Float*)value)->body); - } - } - } else if (obj->body.otype == uris->patch_Get) { - const LV2_Atom_URID* accept = NULL; - const LV2_Atom_Int* n_peaks = NULL; - lv2_atom_object_get_typed( - obj, - uris->patch_accept, &accept, uris->atom_URID, - peaks_uris->peaks_total, &n_peaks, peaks_uris->atom_Int, 0); - if (accept && accept->body == peaks_uris->peaks_PeakUpdate) { - // Received a request for peaks, prepare for transmission - peaks_sender_start(&self->psend, - self->sample->data, - self->sample->info.frames, - n_peaks->body); - } else { - // Received a get message, emit our state (probably to UI) - lv2_atom_forge_frame_time(&self->forge, self->frame_offset); - write_set_file(&self->forge, &self->uris, - self->sample->path, - self->sample->path_len); - } - } else { - lv2_log_trace(&self->logger, - "Unknown object type %d\n", obj->body.otype); - } - } else { - lv2_log_trace(&self->logger, - "Unknown event type %d\n", ev->body.type); - } + // Process this event + handle_event(self, ev); } + // Use available space after any emitted events to send peaks peaks_sender_send(&self->psend, &self->forge, sample_count, self->frame_offset); - // Render the sample (possibly already in progress) - if (self->play) { - uint32_t f = self->frame; - const uint32_t lf = self->sample->info.frames; - - for (pos = 0; pos < start_frame; ++pos) { - output[pos] = 0; - } - - for (; pos < sample_count && f < lf; ++pos, ++f) { - output[pos] = self->sample->data[f] * self->gain; - } - - self->frame = f; - - if (f == lf) { - self->play = false; - } - } - - // Add zeros to end if sample not long enough (or not playing) - for (; pos < sample_count; ++pos) { - output[pos] = 0.0f; - } + // Render output for the rest of the cycle past the last event + render(self, self->frame_offset, sample_count); } static LV2_State_Status diff --git a/plugins/eg-sampler.lv2/sampler.ttl b/plugins/eg-sampler.lv2/sampler.ttl index c6103a3..7672dba 100644 --- a/plugins/eg-sampler.lv2/sampler.ttl +++ b/plugins/eg-sampler.lv2/sampler.ttl @@ -56,7 +56,8 @@ lv2:name "Out" ] ; state:state [ - + ; + 1.0 ] . -- cgit v1.2.1