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..
Copyright 2020-2022 David Robillard <d@drobilla.net>
SPDX-License-Identifier: ISC
.. default-domain:: c
.. highlight:: c
#######
Plugins
#######
After bundles are loaded,
all discovered plugins can be accessed via :func:`lilv_world_get_all_plugins`:
.. code-block:: c
LilvPlugins* plugins = lilv_world_get_all_plugins(world);
:struct:`LilvPlugins` is a collection of plugins that can be accessed by index or plugin URI.
The convenicne macro :macro:`LILV_FOREACH` is provided to make iterating over collections simple.
For example, to print the URI of every plugin:
.. code-block:: c
LILV_FOREACH (plugins, i, list) {
const LilvPlugin* p = lilv_plugins_get(list, i);
printf("%s\n", lilv_node_as_uri(lilv_plugin_get_uri(p)));
}
}
More typically,
you want to load a specific plugin,
which can be done with :func:`lilv_plugins_get_by_uri`:
.. code-block:: c
LilvNode* plugin_uri = lilv_new_uri(world, "http://example.org/Osc");
const LilvPlugin* plugin = lilv_plugins_get_by_uri(list, plugin_uri);
:struct:`LilvPlugin` has various accessors that can be used to get information about the plugin.
See the :doc:`API reference <api/lilv_plugin>` for details.
*********
Instances
*********
:struct:`LilvPlugin` only represents the data of the plugin,
it does not load or access the actual plugin code.
To do that, you must instantiate a plugin to create :struct:`LilvInstance`:
.. code-block:: c
LilvInstance* instance = lilv_plugin_instantiate(plugin, 48000.0, NULL);
Connecting Ports
================
Before running a plugin instance, its ports must be connected to some data.
This is done with :func:`lilv_instance_connect_port`.
Assuming the plugins has two control input ports and one audio output port,
in that order:
.. code-block:: c
float control_in_1 = 0.0f;
float control_in_2 = 0.0f;
float audio_out[128];
lilv_instance_connect_port(instance, 0, &control_in_1);
lilv_instance_connect_port(instance, 1, &control_in_2);
lilv_instance_connect_port(instance, 2, &audio_out);
Processing Data
===============
Once the ports are connected, the instance can be activated and run:
.. code-block:: c
lilv_instance_activate(instance);
lilv_instance_run(instance, 128);
// Copy buffers around and probably run several times here...
lilv_instance_deactivate(instance);
Once you are done with an instance,
it can be destroyed with :func:`lilv_instance_free`:
.. code-block:: c
lilv_instance_free(instance);
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