*: split rototiller.[ch] into lib and main

This is a first approximation of separating the core modules and
threaded rendering from the cli-centric rototiller program and
its sdl+drm video backends.

Unfortunately this seemed to require switching over to libtool
archives (.la) to permit consolidating the per-lib and
per-module .a files into the librototiller.a and linking just
with librototiller.a to depend on the aggregate of
libs+modules+librototiller-glue in a simple fashion.

If an alternative to .la comes up I will switch over to it,
using libtool really slows down the build process.

Those are implementation/build system details though.  What's
important in these changes is establishing something resembling a
librototiller API boundary, enabling creating alternative
frontends which vendor this tree as a submodule and link just to
librototiller.{la,a} for all the modules+threaded rendering of
them, while providing their own fb_ops_t for outputting into, and
their own settings applicators for driving the modules setup.

1 files changed, 340 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..5180529
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,340 @@
+#include <assert.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#include "settings.h"
+#include "setup.h"
+#include "fb.h"
+#include "fps.h"
+#include "rototiller.h"
+#include "util.h"
+
+/* Copyright (C) 2016 Vito Caputo <vcaputo@pengaru.com> */
+
+#define NUM_FB_PAGES	3
+/* ^ By triple-buffering, we can have a page tied up being displayed, another
+ * tied up submitted and waiting for vsync, and still not block on getting
+ * another page so we can begin rendering another frame before vsync.  With
+ * just two pages we end up twiddling thumbs until the vsync arrives.
+ */
+#define DEFAULT_VIDEO	"sdl"
+
+extern fb_ops_t			drm_fb_ops;
+extern fb_ops_t			sdl_fb_ops;
+fb_ops_t			*fb_ops;
+
+typedef struct rototiller_t {
+	const rototiller_module_t	*module;
+	void				*module_context;
+	pthread_t			thread;
+	fb_t				*fb;
+	struct timeval			start_tv;
+	unsigned			ticks_offset;
+} rototiller_t;
+
+static rototiller_t		rototiller;
+
+
+typedef struct argv_t {
+	const char	*module;
+	const char	*video;
+
+	unsigned	use_defaults:1;
+	unsigned	help:1;
+} argv_t;
+
+/*
+ * ./rototiller --video=drm,dev=/dev/dri/card3,connector=VGA-1,mode=640x480@60
+ * ./rototiller --video=sdl,size=640x480
+ * ./rototiller --module=roto,foo=bar,module=settings
+ * ./rototiller --defaults
+ */
+static int parse_argv(int argc, const char *argv[], argv_t *res_args)
+{
+	int	i;
+
+	assert(argc > 0);
+	assert(argv);
+	assert(res_args);
+
+	/* this is intentionally being kept very simple, no new dependencies like getopt. */
+
+	for (i = 1; i < argc; i++) {
+		if (!strncmp("--video=", argv[i], 8)) {
+			res_args->video = &argv[i][8];
+		} else if (!strncmp("--module=", argv[i], 9)) {
+			res_args->module = &argv[i][9];
+		} else if (!strcmp("--defaults", argv[i])) {
+			res_args->use_defaults = 1;
+		} else if (!strcmp("--help", argv[i])) {
+			res_args->help = 1;
+		} else {
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+
+typedef struct setup_t {
+	settings_t	*module;
+	settings_t	*video;
+} setup_t;
+
+/* FIXME: this is unnecessarily copy-pasta, i think modules should just be made
+ * more generic to encompass the setting up uniformly, then basically
+ * subclass the video backend vs. renderer stuff.
+ */
+
+/* select video backend if not yet selected, then setup the selected backend. */
+static int setup_video(settings_t *settings, setting_desc_t **next_setting)
+{
+	const char	*video;
+
+	/* XXX: there's only one option currently, so this is simple */
+	video = settings_get_key(settings, 0);
+	if (!video) {
+		setting_desc_t	*desc;
+		const char	*values[] = {
+#ifdef HAVE_DRM
+					"drm",
+#endif
+					"sdl",
+					NULL,
+				};
+		int		r;
+
+		r = setting_desc_clone(&(setting_desc_t){
+						.name = "Video Backend",
+						.key = NULL,
+						.regex = "[a-z]+",
+						.preferred = DEFAULT_VIDEO,
+						.values = values,
+						.annotations = NULL
+					}, next_setting);
+		if (r < 0)
+			return r;
+
+		return 1;
+	}
+
+	/* XXX: this is kind of hacky for now */
+#ifdef HAVE_DRM
+	if (!strcmp(video, "drm")) {
+		fb_ops = &drm_fb_ops;
+
+		return drm_fb_ops.setup(settings, next_setting);
+	} else
+#endif
+	if (!strcmp(video, "sdl")) {
+		fb_ops = &sdl_fb_ops;
+
+		return sdl_fb_ops.setup(settings, next_setting);
+	}
+
+	return -EINVAL;
+}
+
+
+/* turn args into settings, automatically applying defaults if appropriate, or interactively if appropriate. */
+/* returns negative value on error, 0 when settings unchanged from args, 1 when changed */
+static int setup_from_args(argv_t *args, setup_t *res_setup)
+{
+	int	r, changes = 0;
+	setup_t	setup;
+
+	setup.module = settings_new(args->module);
+	if (!setup.module)
+		return -ENOMEM;
+
+	setup.video = settings_new(args->video);
+	if (!setup.video) {
+		settings_free(setup.module);
+
+		return -ENOMEM;
+	}
+
+	r = setup_interactively(setup.module, rototiller_module_setup, args->use_defaults);
+	if (r < 0) {
+		settings_free(setup.module);
+		settings_free(setup.video);
+
+		return r;
+	}
+
+	if (r)
+		changes = 1;
+
+	r = setup_interactively(setup.video, setup_video, args->use_defaults);
+	if (r < 0) {
+		settings_free(setup.module);
+		settings_free(setup.video);
+
+		return r;
+	}
+
+	if (r)
+		changes = 1;
+
+	*res_setup = setup;
+
+	return changes;
+}
+
+
+static int print_setup_as_args(setup_t *setup)
+{
+	char	*module_args, *video_args;
+	char	buf[64];
+	int	r;
+
+	module_args = settings_as_arg(setup->module);
+	if (!module_args) {
+		r = -ENOMEM;
+
+		goto _out;
+	}
+
+	video_args = settings_as_arg(setup->video);
+	if (!video_args) {
+		r = -ENOMEM;
+
+		goto _out_module;
+	}
+
+	r = printf("\nConfigured settings as flags:\n  --module=%s --video=%s\n\nPress enter to continue...\n",
+		module_args,
+		video_args);
+
+	if (r < 0)
+		goto _out_video;
+
+	(void) fgets(buf, sizeof(buf), stdin);
+
+_out_video:
+	free(video_args);
+_out_module:
+	free(module_args);
+_out:
+	return r;
+}
+
+
+static int print_help(void)
+{
+	return printf(
+		"Run without any flags or partial settings for interactive mode.\n"
+		"\n"
+		"Supported flags:\n"
+		"  --defaults	use defaults for unspecified settings\n"
+		"  --help	this help\n"
+		"  --module=	module settings\n"
+		"  --video=	video settings\n"
+		);
+}
+
+
+static unsigned get_ticks(const struct timeval *start, const struct timeval *now, unsigned offset)
+{
+	return (unsigned)((now->tv_sec - start->tv_sec) * 1000 + (now->tv_usec - start->tv_usec) / 1000) + offset;
+}
+
+
+static void * rototiller_thread(void *_rt)
+{
+	rototiller_t	*rt = _rt;
+	struct timeval	now;
+
+	for (;;) {
+		fb_page_t	*page;
+		unsigned	ticks;
+
+		page = fb_page_get(rt->fb);
+
+		gettimeofday(&now, NULL);
+		ticks = get_ticks(&rt->start_tv, &now, rt->ticks_offset);
+
+		rototiller_module_render(rt->module, rt->module_context, ticks, &page->fragment);
+
+		fb_page_put(rt->fb, page);
+	}
+
+	return NULL;
+}
+
+
+/* When run with partial/no arguments, if stdin is a tty, enter an interactive setup.
+ * If stdin is not a tty, or if --defaults is supplied in argv, default settings are used.
+ * If any changes to the settings occur in the course of execution, either interactively or
+ * throught --defaults, then print out the explicit CLI invocation usable for reproducing
+ * the invocation.
+ */
+int main(int argc, const char *argv[])
+{
+	setup_t		setup = {};
+	argv_t		args = {};
+	int		r;
+
+	exit_if(parse_argv(argc, argv, &args) < 0,
+		"unable to process arguments");
+
+	if (args.help)
+		return print_help() < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+
+	exit_if((r = setup_from_args(&args, &setup)) < 0,
+		"unable to setup: %s", strerror(-r));
+
+	exit_if(r && print_setup_as_args(&setup) < 0,
+		"unable to print setup");
+
+	exit_if(!(rototiller.module = rototiller_lookup_module(settings_get_key(setup.module, 0))),
+		"unable to lookup module from settings \"%s\"", settings_get_key(setup.module, 0));
+
+	exit_if((r = fb_new(fb_ops, setup.video, NUM_FB_PAGES, &rototiller.fb)) < 0,
+		"unable to create fb: %s", strerror(-r));
+
+	exit_if(!fps_setup(),
+		"unable to setup fps counter");
+
+	exit_if((r = rototiller_init()) < 0,
+		"unable to initialize librototiller: %s", strerror(-r));
+
+	gettimeofday(&rototiller.start_tv, NULL);
+	exit_if((r = rototiller_module_create_context(
+						rototiller.module,
+						get_ticks(&rototiller.start_tv,
+							&rototiller.start_tv,
+							rototiller.ticks_offset),
+						&rototiller.module_context)) < 0,
+		"unable to create module context: %s", strerror(-r));
+
+	pexit_if(pthread_create(&rototiller.thread, NULL, rototiller_thread, &rototiller) != 0,
+		"unable to create dispatch thread");
+
+	for (;;) {
+		if (fb_flip(rototiller.fb) < 0)
+			break;
+
+		fps_print(rototiller.fb);
+	}
+
+	pthread_cancel(rototiller.thread);
+	pthread_join(rototiller.thread, NULL);
+	rototiller_shutdown();
+
+	if (rototiller.module_context)
+		rototiller.module->destroy_context(rototiller.module_context);
+
+	fb_free(rototiller.fb);
+
+	return EXIT_SUCCESS;
+}