modules/playit: add an .IT file music player module

Rudimentary .IT file music playback via libplayit.

When seekable=on, the file is 100% pre-rendered at context
create, then simply copied into the audio queue @ render_audio.

When seekable=off, the file is mixed incrementally per-frame @
render_audio in max of bufsize=N_frames increments.  The bufsize
here basically just determines the maximum time spent rendering
audio in a single go, and how much tolerance of frame delays due
to slow rendering there will be before dropouts occur.

3 files changed, 228 insertions, 0 deletions

diff --git a/src/modules/Makefile.am b/src/modules/Makefile.am
index 52d6180..0a01480 100644
--- a/src/modules/Makefile.am
+++ b/src/modules/Makefile.am
@@ -14,6 +14,7 @@ SUBDIRS =			\
 		pixbounce	\
 		plasma		\
 		plato		\
+		playit		\
 		ray		\
 		rkt		\
 		roto		\
diff --git a/src/modules/playit/Makefile.am b/src/modules/playit/Makefile.am
new file mode 100644
index 0000000..eec7be8
--- /dev/null
+++ b/src/modules/playit/Makefile.am
@@ -0,0 +1,3 @@
+noinst_LTLIBRARIES = libplayit.la
+libplayit_la_SOURCES = playit.c
+libplayit_la_CPPFLAGS = -I@top_srcdir@/src -I@top_srcdir@/src/libs/playit/src
diff --git a/src/modules/playit/playit.c b/src/modules/playit/playit.c
new file mode 100644
index 0000000..191bd41
--- /dev/null
+++ b/src/modules/playit/playit.c
@@ -0,0 +1,224 @@
+#include <stdint.h>
+#include <stdio.h>
+
+#include <playit.h>
+
+#include "til.h"
+#include "til_audio.h"
+#include "til_fb.h"
+#include "til_stream.h"
+
+/* Copyright (C) 2023 - Vito Caputo <vcaputo@pengaru.com> */
+
+/* .IT file playback module via libplayit (SchismTracker) */
+
+#define PLAYIT_DEFAULT_ITFILE	"play.it"
+#define PLAYIT_DEFAULT_SEEKABLE	0
+#define PLAYIT_DEFAULT_BUFSIZE	4096
+
+
+typedef struct playit_context_t {
+	til_module_context_t	til_module_context;
+	unsigned		last_frame;
+
+	playit_t		*playit;
+	til_audio_context_t	*audio;
+	unsigned		paused:1;
+	int16_t			buf[];
+} playit_context_t;
+
+typedef struct playit_setup_t {
+	til_setup_t	til_setup;
+
+	unsigned	seekable;
+	unsigned	bufsize;
+	char		itfile[];
+} playit_setup_t;
+
+
+static void playit_audio_seeked(void *hook_context, const til_audio_context_t *audio_context, unsigned ticks);
+static void playit_audio_paused(void *hook_context, const til_audio_context_t *audio_context);
+static void playit_audio_unpaused(void *hook_context, const til_audio_context_t *audio_context);
+
+
+til_audio_hooks_t	playit_audio_hooks = {
+	playit_audio_seeked,
+	playit_audio_paused,
+	playit_audio_unpaused,
+};
+
+
+static void playit_audio_seeked(void *hook_context, const til_audio_context_t *audio_context, unsigned ticks)
+{
+	playit_context_t	*ctxt = hook_context;
+
+	assert(((playit_setup_t *)ctxt->til_module_context.setup)->seekable);
+
+	playit_seek(ctxt->playit, ticks * 44.1f);
+}
+
+
+static void playit_audio_paused(void *hook_context, const til_audio_context_t *audio_context)
+{
+	playit_context_t	*ctxt = hook_context;
+
+	ctxt->paused = 1;
+}
+
+
+static void playit_audio_unpaused(void *hook_context, const til_audio_context_t *audio_context)
+{
+	playit_context_t	*ctxt = hook_context;
+
+	ctxt->paused = 0;
+}
+
+
+static til_module_context_t * playit_create_context(const til_module_t *module, til_stream_t *stream, unsigned seed, unsigned ticks, unsigned n_cpus, til_setup_t *setup)
+{
+	playit_setup_t		*s = (playit_setup_t *)setup;
+	playit_context_t	*ctxt;
+
+	ctxt = til_module_context_new(module, sizeof(playit_context_t) + s->bufsize * sizeof(ctxt->buf[0]) * 2, stream, seed, ticks, n_cpus, setup);
+	if (!ctxt)
+		return NULL;
+
+	ctxt->audio = til_stream_get_audio_context(stream);
+	if (!ctxt->audio)
+		return til_module_context_free(&ctxt->til_module_context);
+
+	if (til_audio_set_hooks(ctxt->audio, &playit_audio_hooks, ctxt) < 0)
+		return til_module_context_free(&ctxt->til_module_context);
+
+	ctxt->playit = playit_open_file(s->itfile, s->seekable ? PLAYIT_FLAG_SEEKABLE : 0);
+	if (!ctxt->playit)
+		return til_module_context_free(&ctxt->til_module_context);
+
+	return &ctxt->til_module_context;
+}
+
+
+static void playit_destroy_context(til_module_context_t *context)
+{
+	playit_context_t	*ctxt = (playit_context_t *)context;
+
+	til_audio_unset_hooks(ctxt->audio, &playit_audio_hooks, ctxt);
+
+	if (ctxt->playit)
+		playit_destroy(ctxt->playit);
+
+	free(ctxt);
+}
+
+
+static void playit_render_audio(til_module_context_t *context, til_stream_t *stream, unsigned ticks)
+{
+	playit_context_t	*ctxt = (playit_context_t *)context;
+	playit_setup_t		*s = (playit_setup_t *)context->setup;
+	size_t			tomix = s->bufsize;
+	unsigned		frame, frames;
+
+	if (ctxt->paused)
+		return;
+
+	tomix -= til_audio_n_queued(ctxt->audio);
+	if (tomix <= 0)
+		return;
+
+	frames = playit_update(ctxt->playit, ctxt->buf, tomix * sizeof(int16_t) * 2, &frame);
+	if (!frames)
+		return;
+
+	til_audio_queue(ctxt->audio, ctxt->buf, frames);
+}
+
+
+static int playit_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup);
+
+
+til_module_t	playit_module = {
+	.create_context = playit_create_context,
+	.destroy_context = playit_destroy_context,
+	.render_audio = playit_render_audio,
+	.setup = playit_setup,
+	.name = "playit",
+	.description = ".IT tracked music file player",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.flags = TIL_MODULE_EXPERIMENTAL,
+};
+
+
+static int playit_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup)
+{
+	til_setting_t	*itfile;
+	til_setting_t	*seekable;
+	til_setting_t	*bufsize;
+	const char	*seekable_values[] = {
+				"off",
+				"on",
+				NULL
+			};
+	int		r;
+
+	r = til_settings_get_and_describe_setting(settings,
+						&(til_setting_spec_t){
+							.name = ".IT file path",
+							.key = "itfile",
+							.preferred = PLAYIT_DEFAULT_ITFILE,
+							.annotations = NULL
+						},
+						&itfile,
+						res_setting,
+						res_desc);
+	if (r)
+		return r;
+
+	r = til_settings_get_and_describe_setting(settings,
+						&(til_setting_spec_t){
+							.name = "Seekable",
+							.key = "seekable",
+							.regex = "^(on|off)",
+							.preferred = seekable_values[PLAYIT_DEFAULT_SEEKABLE],
+							.values = seekable_values,
+							.annotations = NULL
+						},
+						&seekable,
+						res_setting,
+						res_desc);
+	if (r)
+		return r;
+
+	r = til_settings_get_and_describe_setting(settings,
+						&(til_setting_spec_t){
+							.name = "Buffer size in frames",
+							.key = "bufsize",
+							.preferred = TIL_SETTINGS_STR(PLAYIT_DEFAULT_BUFSIZE),
+						},
+						&bufsize,
+						res_setting,
+						res_desc);
+	if (r)
+		return r;
+
+	if (res_setup) {
+		playit_setup_t	*setup;
+		size_t		itfile_len = strlen(itfile->value);
+
+		setup = til_setup_new(settings, sizeof(*setup) + itfile_len + 1, NULL, &playit_module);
+		if (!setup)
+			return -ENOMEM;
+
+		strncpy(setup->itfile, itfile->value, itfile_len);
+
+		r = til_value_to_pos(seekable_values, seekable->value, &setup->seekable);
+		if (r < 0)
+			return til_setup_free_with_failed_setting_ret_err(&setup->til_setup, seekable, res_setting, r);
+
+		if (sscanf(bufsize->value, "%u", &setup->bufsize) != 1)
+			return til_setup_free_with_failed_setting_ret_err(&setup->til_setup, bufsize, res_setting, -EINVAL);
+
+		*res_setup = &setup->til_setup;
+	}
+
+	return 0;
+}