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-rw-r--r--plugins/eg05-scope.lv2/README.txt10
-rw-r--r--plugins/eg05-scope.lv2/examploscope.c82
-rw-r--r--plugins/eg05-scope.lv2/manifest.ttl.in3
3 files changed, 59 insertions, 36 deletions
diff --git a/plugins/eg05-scope.lv2/README.txt b/plugins/eg05-scope.lv2/README.txt
index ec3578b..122794c 100644
--- a/plugins/eg05-scope.lv2/README.txt
+++ b/plugins/eg05-scope.lv2/README.txt
@@ -1,17 +1,19 @@
== Simple Oscilloscope ==
-This plugin displays the wave-form of an incoming audio-signal using a simple
+This plugin displays the waveform of an incoming audio signal using a simple
GTK+Cairo GUI.
This plugin illustrates:
-- UI <==> Plugin communication via LV2 atom events
-- LV2 Atom vector usage and resize-port extension
+- UI <==> Plugin communication via http://lv2plug.in/ns/ext/atom/[LV2 Atom] events
+- Atom vector usage and resize-port extension
- Save/Restore UI state by communicating state to backend
+- Saving simple key/value state via the http://lv2plug.in/ns/ext/state/[LV2 State] extension
- Cairo drawing and partial exposure
This plugin intends to outline the basics for building visualization plugins
-that rely on Atom communication. The UI looks likean oscilloscope, but is not a real oscilloscope implementation:
+that rely on atom communication. The UI looks like an oscilloscope, but is not
+a real oscilloscope implementation:
- There is no display synchronisation, results will depend on LV2 host.
- It displays raw audio samples, which a proper scope must not do.
diff --git a/plugins/eg05-scope.lv2/examploscope.c b/plugins/eg05-scope.lv2/examploscope.c
index ff64866..31e757a 100644
--- a/plugins/eg05-scope.lv2/examploscope.c
+++ b/plugins/eg05-scope.lv2/examploscope.c
@@ -25,7 +25,14 @@
#include "./uris.h"
-/** Private plugin instance structure. */
+/**
+ ==== Private Plugin Instance Structure ====
+
+ In addition to the usual port buffers and features, this plugin stores the
+ state of the UI here, so it can be opened and closed without losing the
+ current settings. The UI state is communicated between the plugin and the
+ UI using atom messages via a sequence port, similarly to MIDI I/O.
+*/
typedef struct {
// Port buffers
float* input[2];
@@ -47,27 +54,24 @@ typedef struct {
uint32_t n_channels;
double rate;
- /* The state of the UI is stored here, so that the GUI can be displayed and
- closed without losing the current settings. It is communicated to the
- UI using atom messages.
- */
+ // UI state
bool ui_active;
bool send_settings_to_ui;
float ui_amp;
uint32_t ui_spp;
} EgScope;
-/** Port indices. */
+/** ==== Port Indices ==== */
typedef enum {
- SCO_CONTROL = 0,
- SCO_NOTIFY = 1,
- SCO_INPUT0 = 2,
- SCO_OUTPUT0 = 3,
- SCO_INPUT1 = 4,
- SCO_OUTPUT1 = 5,
+ SCO_CONTROL = 0, // Event input
+ SCO_NOTIFY = 1, // Event output
+ SCO_INPUT0 = 2, // Audio input 0
+ SCO_OUTPUT0 = 3, // Audio output 0
+ SCO_INPUT1 = 4, // Audio input 1 (stereo variant)
+ SCO_OUTPUT1 = 5, // Audio input 2 (stereo variant)
} PortIndex;
-/** Create plugin instance. */
+/** ==== Instantiate Method ==== */
static LV2_Handle
instantiate(const LV2_Descriptor* descriptor,
double rate,
@@ -125,7 +129,7 @@ instantiate(const LV2_Descriptor* descriptor,
return (LV2_Handle)self;
}
-/** Connect a port to a buffer. */
+/** ==== Connect Port Method ==== */
static void
connect_port(LV2_Handle handle,
uint32_t port,
@@ -156,41 +160,49 @@ connect_port(LV2_Handle handle,
}
/**
- Forge vector of raw data.
-
- @param forge Forge to use.
- @param uris Mapped URI identifiers.
- @param channel Channel ID to transmit.
- @param n_samples Number of audio samples to transmit.
- @param data Actual audio data.
+ ==== Utility Function: `tx_rawaudio` ====
+
+ This function forges a message for sending a vector of raw data. The object
+ is a http://lv2plug.in/ns/ext/atom#Blank[Blank] with a few properties, like:
+ [source,txt]
+ --------
+ []
+ a sco:RawAudio ;
+ sco:channelID 0 ;
+ sco:audioData [ 0.0, 0.0, ... ] .
+ --------
+
+ where the value of the `sco:audioData` property, `[ 0.0, 0.0, ... ]`, is a
+ http://lv2plug.in/ns/ext/atom#Vector[Vector] of
+ http://lv2plug.in/ns/ext/atom#Float[Float].
*/
static void
tx_rawaudio(LV2_Atom_Forge* forge,
ScoLV2URIs* uris,
const int32_t channel,
const size_t n_samples,
- void* data)
+ const float* data)
{
LV2_Atom_Forge_Frame frame;
- // Forge container object of type 'rawaudio'
+ // Forge container object of type 'RawAudio'
lv2_atom_forge_frame_time(forge, 0);
lv2_atom_forge_blank(forge, &frame, 1, uris->RawAudio);
- // Add integer attribute 'channelid'
+ // Add integer 'channelID' property
lv2_atom_forge_property_head(forge, uris->channelID, 0);
lv2_atom_forge_int(forge, channel);
- // Add vector of floats raw 'audiodata'
+ // Add vector of floats 'audioData' property
lv2_atom_forge_property_head(forge, uris->audioData, 0);
lv2_atom_forge_vector(
forge, sizeof(float), uris->atom_Float, n_samples, data);
- // Close off atom-object
+ // Close off object
lv2_atom_forge_pop(forge, &frame);
}
-/** Process a block of audio */
+/** ==== Run Method ==== */
static void
run(LV2_Handle handle, uint32_t n_samples)
{
@@ -298,6 +310,16 @@ cleanup(LV2_Handle handle)
free(handle);
}
+
+/**
+ ==== State Methods ====
+
+ This plugin's state consists of two basic properties: one `int` and one
+ `float`. No files are used. Note these values are POD, but not portable,
+ since different machines may have a different integer endianness or floating
+ point format. However, since standard Atom types are used, a good host will
+ be able to save them portably as text anyway.
+*/
static LV2_State_Status
state_save(LV2_Handle instance,
LV2_State_Store_Function store,
@@ -310,11 +332,6 @@ state_save(LV2_Handle instance,
return LV2_STATE_SUCCESS;
}
- /* Store state values. Note these values are POD, but not portable, since
- different machines may have a different integer endianness or floating
- point format. However, since standard Atom types are used, a good host
- will be able to save them portably as text anyway. */
-
store(handle, self->uris.ui_spp,
(void*)&self->ui_spp, sizeof(uint32_t),
self->uris.atom_Int,
@@ -368,6 +385,7 @@ extension_data(const char* uri)
return NULL;
}
+/** ==== Plugin Descriptors ==== */
static const LV2_Descriptor descriptor_mono = {
SCO_URI "#Mono",
instantiate,
diff --git a/plugins/eg05-scope.lv2/manifest.ttl.in b/plugins/eg05-scope.lv2/manifest.ttl.in
index 028a673..a64aff1 100644
--- a/plugins/eg05-scope.lv2/manifest.ttl.in
+++ b/plugins/eg05-scope.lv2/manifest.ttl.in
@@ -2,16 +2,19 @@
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix ui: <http://lv2plug.in/ns/extensions/ui#> .
+# ==== Mono plugin variant ====
<http://lv2plug.in/plugins/eg-scope#Mono>
a lv2:Plugin ;
lv2:binary <examploscope@LIB_EXT@> ;
rdfs:seeAlso <examploscope.ttl> .
+# ==== Stereo plugin variant ====
<http://lv2plug.in/plugins/eg-scope#Stereo>
a lv2:Plugin ;
lv2:binary <examploscope@LIB_EXT@> ;
rdfs:seeAlso <examploscope.ttl> .
+# ==== Gtk 2.0 UI ====
<http://lv2plug.in/plugins/eg-scope#ui>
a ui:GtkUI ;
ui:binary <examploscope_ui@LIB_EXT@> ;
generated by cgit v1.2.1 (git 2.18.0) at 2024-12-28 14:08:37 +0000