Complete example of a CLAP plugin based on template. (#1)

- Swaps left and right audio channels.
- Logs (CLAP) note on/off messages.

Makefile

@@ -10,7 +10,7 @@ V_SRC = $(wildcard $(SOURCEDIR)/*.v)
 DEBUG ?= 0
 RELEASE ?= 0
 ifeq ($(DEBUG),1)
-	V_FLAGS = -cg -show-c-output
+	V_FLAGS = -cg -show-c-output -trace-calls
 else ifeq ($(RELEASE),1)
 	V_FLAGS = -prod -skip-unused -cflags -fvisibility=hidden
 endif

src/c_abi.v

@@ -4,13 +4,15 @@ module plugin
 #include "clap/clap.h"
 
 enum ClapProcessStatus {
-	clap_process_error = 0
-	clap_process_continue = 1
-	clap_process_continue_if_not_quiet = 2
-	clap_process_tail = 3
-	clap_process_sleep = 4
+	error                 = 0
+	@continue             = 1
+	continue_if_not_quiet = 2
+	tail                  = 3
+	sleep                 = 4
 }
 
+type C.clap_id = u32
+
 @[typedef]
 struct C.clap_version_t {
 	major    u32 = u32(C.CLAP_VERSION_MAJOR)
@@ -37,10 +39,10 @@ struct C.clap_plugin_t {
 	desc        &C.clap_plugin_descriptor_t @[required]
 	plugin_data voidptr                     @[required]
 
-	init             fn (&C.clap_plugin_t) bool                @[required]
-	destroy          fn (&C.clap_plugin_t)                     @[required]
-	activate         fn (&C.clap_plugin_t, f64, u32, u32) bool @[required]
-	deactivate       fn (&C.clap_plugin_t)                     @[required]
+	init             fn (&C.clap_plugin_t) bool                                 @[required]
+	destroy          fn (&C.clap_plugin_t)                                      @[required]
+	activate         fn (&C.clap_plugin_t, f64, u32, u32) bool                  @[required]
+	deactivate       fn (&C.clap_plugin_t)                                      @[required]
 	start_processing fn (&C.clap_plugin_t) bool
 	stop_processing  fn (&C.clap_plugin_t)
 	reset            fn (&C.clap_plugin_t)
@@ -49,9 +51,10 @@ struct C.clap_plugin_t {
 	on_main_thread   fn (&C.clap_plugin_t)
 }
 
-@[typedef]
+@[heap; typedef]
 struct C.clap_host_t {
-	clap_version C.clap_version_t
+	clap_version  C.clap_version_t
+	get_extension fn (&C.clap_host_t, &char) voidptr
 }
 
 @[typedef]
@@ -70,8 +73,79 @@ struct C.clap_plugin_entry_t {
 }
 
 @[typedef]
-struct C.clap_process_t
+struct C.clap_process_t {
+	steady_time         i64
+	frames_count        u32
+	transport           &C.clap_event_transport_t
+	audio_inputs        &C.clap_audio_buffer_t
+	audio_inputs_count  u32
+	audio_outputs_count u32
+	in_events           &C.clap_input_events_t
+	out_events          &C.clap_output_events_t
+mut:
+	audio_outputs &C.clap_audio_buffer_t
+}
+
+@[typedef]
+struct C.clap_event_transport_t {}
+
+@[typedef]
+struct C.clap_audio_buffer_t {
+	channel_count u32
+	latency       u32
+	constant_mask u64
+mut:
+	data32 &&f32
+	data64 &&f64
+}
+
+@[typedef]
+struct C.clap_input_events_t {
+	ctx  voidptr
+	size fn (&C.clap_input_events_t) u32
+	// TODO: How to avoid `voidptr` and use header/event structs instead?
+	get fn (&C.clap_input_events_t, u32) voidptr
+}
+
+@[typedef]
+struct C.clap_event_header_t {
+	size     u32
+	time     u32
+	space_id u16
+	@type    u16
+	flags    u32
+}
+
+// TODO: Why doesn't typedef C structs work here?
+struct ClapEventNote {
+	C.clap_event_header_t
+	note_id    int
+	port_index i16
+	channel    i16
+	key        i16
+	velocity   f64
+}
+
+enum ClapEventType as u16 {
+	note_on             = 0
+	note_off            = 1
+	note_choke          = 2
+	note_end            = 3
+	note_expression     = 4
+	param_value         = 5
+	param_mod           = 6
+	param_gesture_begin = 7
+	param_gesture_end   = 8
+	transport           = 9
+	midi                = 10
+	midi_sysex          = 11
+	midi2               = 12
+}
+
+@[typedef]
+struct C.clap_output_events_t {}
 
 const clap_plugin_factory_id = unsafe { (&char(C.CLAP_PLUGIN_FACTORY_ID)).vstring() }
+const clap_core_event_space_id = u16(C.CLAP_CORE_EVENT_SPACE_ID)
 
 fn C.clap_version_is_compatible(C.clap_version_t) bool

src/ext_audio_ports.v

@@ -0,0 +1,29 @@
+module plugin
+
+const clap_ext_audio_ports = unsafe { (&char(C.CLAP_EXT_AUDIO_PORTS)).vstring() }
+const clap_port_stereo = unsafe { (&char(C.CLAP_PORT_STEREO)).vstring() }
+const clap_port_mono = unsafe { (&char(C.CLAP_PORT_MONO)).vstring() }
+
+@[typedef]
+struct C.clap_audio_port_info_t {
+mut:
+	id            C.clap_id
+	name          [256]char
+	flags         u32
+	channel_count u32
+	port_type     &char
+	in_place_pair C.clap_id
+}
+
+@[typedef]
+struct C.clap_plugin_audio_ports_t {
+	count fn (&C.clap_plugin_t, bool) u32
+	get   fn (&C.clap_plugin_t, u32, bool, &C.clap_audio_port_info_t) bool
+}
+
+enum ClapAudioPortFlags as u32 {
+	is_main                     = 1 << 0
+	supports_64_bits            = 1 << 1
+	prefers_64_bits             = 1 << 2
+	requires_common_sample_size = 1 << 3
+}

src/ext_latency.v

@@ -0,0 +1,8 @@
+module plugin
+
+const clap_ext_latency = unsafe { (&char(C.CLAP_EXT_LATENCY)).vstring() }
+
+@[typedef]
+struct C.clap_plugin_latency_t {
+	get fn (&C.clap_plugin_t) u32
+}

src/ext_note_ports.v

@@ -0,0 +1,25 @@
+module plugin
+
+const clap_ext_note_ports = unsafe { (&char(C.CLAP_EXT_NOTE_PORTS)).vstring() }
+
+@[typedef]
+struct C.clap_note_port_info_t {
+mut:
+	id                 C.clap_id
+	supported_dialects u32
+	preferred_dialect  u32
+	name               [256]char
+}
+
+@[typedef]
+struct C.clap_plugin_note_ports_t {
+	count fn (&C.clap_plugin_t, bool) u32
+	get   fn (&C.clap_plugin_t, u32, bool, &C.clap_note_port_info_t) bool
+}
+
+enum ClapNoteDialect as u32 {
+	clap     = 1 << 0
+	midi     = 1 << 1
+	midi_mpe = 1 << 2
+	midi2    = 1 << 3
+}

src/main.v

@@ -6,4 +6,4 @@ module plugin
 // Remove "const" so you get:
 // CLAP_EXPORT extern clap_plugin_entry_t clap_entry;
 @[markused]
-__global clap_entry = _plugin_entry
+__global clap_entry = plugin_entry