3 files changed, 159 insertions, 1 deletions
diff --git a/src/modules/Makefile.am b/src/modules/Makefile.am
index 83adbc5..f88879e 100644
--- a/src/modules/Makefile.am
+++ b/src/modules/Makefile.am
@@ -1 +1 @@
-SUBDIRS = blinds checkers compose drizzle flui2d julia meta2d moire montage pixbounce plasma plato ray roto rtv shapes snow sparkler spiro stars submit swab swarm voronoi
+SUBDIRS = blinds checkers compose drizzle flui2d julia meta2d moire montage pixbounce plasma plato ray roto rtv shapes snow sparkler spiro stars strobe submit swab swarm voronoi
diff --git a/src/modules/strobe/Makefile.am b/src/modules/strobe/Makefile.am
new file mode 100644
index 0000000..8bac057
--- /dev/null
+++ b/src/modules/strobe/Makefile.am
@@ -0,0 +1,3 @@
+noinst_LTLIBRARIES = libstrobe.la
+libstrobe_la_SOURCES = strobe.c
+libstrobe_la_CPPFLAGS = -I@top_srcdir@/src
diff --git a/src/modules/strobe/strobe.c b/src/modules/strobe/strobe.c
new file mode 100644
index 0000000..4616df4
--- /dev/null
+++ b/src/modules/strobe/strobe.c
@@ -0,0 +1,155 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "til.h"
+#include "til_fb.h"
+#include "til_module_context.h"
+
+/* Dead-simple strobe light, initially made to try simulate this contraption:
+ * https://en.wikipedia.org/wiki/Dreamachine
+ *
+ * But it might actually have some general utility in compositing.
+ */
+
+/* Copyright (C) 2022 Vito Caputo <vcaputo@pengaru.com> */
+
+/* TODO:
+ *	- Make period setting more flexible
+ *	- Currently if the frame rate can't keep up with the period, strobe will
+ *	  just stick on.  There should probably be a force_flash={yes,no} setting
+ *	  to ensure a flash still occurs when the frame rate can't keep up.
+ */
+
+#define	STROBE_DEFAULT_PERIOD		.1
+
+typedef struct strobe_setup_t {
+	til_setup_t		til_setup;
+	float			period;
+} strobe_setup_t;
+
+typedef struct strobe_context_t {
+	til_module_context_t	til_module_context;
+	strobe_setup_t		setup;
+	unsigned		ticks;
+	unsigned		flash:1;
+} strobe_context_t;
+
+
+static strobe_setup_t strobe_default_setup = {
+	.period = STROBE_DEFAULT_PERIOD,
+};
+
+
+static til_module_context_t * strobe_create_context(unsigned seed, unsigned ticks, unsigned n_cpus, til_setup_t *setup)
+{
+	strobe_context_t	*ctxt;
+
+	if (!setup)
+		setup = &strobe_default_setup.til_setup;
+
+	ctxt = til_module_context_new(sizeof(strobe_context_t), seed, ticks, n_cpus);
+	if (!ctxt)
+		return NULL;
+
+	ctxt->setup = *(strobe_setup_t *)setup;
+	ctxt->ticks = ticks;
+
+	return &ctxt->til_module_context;
+}
+
+
+static void strobe_prepare_frame(til_module_context_t *context, unsigned ticks, til_fb_fragment_t **fragment_ptr, til_frame_plan_t *res_frame_plan)
+{
+	strobe_context_t	*ctxt = (strobe_context_t *)context;
+
+	*res_frame_plan = (til_frame_plan_t){ .fragmenter = til_fragmenter_slice_per_cpu };
+
+	if (ticks - ctxt->ticks >= (unsigned)(ctxt->setup.period * 1000.f))
+		ctxt->flash = 1;
+}
+
+
+static void strobe_render_fragment(til_module_context_t *context, unsigned ticks, unsigned cpu, til_fb_fragment_t **fragment_ptr)
+{
+	strobe_context_t	*ctxt = (strobe_context_t *)context;
+	til_fb_fragment_t	*fragment = *fragment_ptr;
+
+	if (!ctxt->flash)
+		return til_fb_fragment_clear(fragment);
+
+	til_fb_fragment_fill(fragment, TIL_FB_DRAW_FLAG_TEXTURABLE, 0xffffffff);
+}
+
+
+static void strobe_finish_frame(til_module_context_t *context, unsigned int ticks, til_fb_fragment_t **fragment_ptr)
+{
+	strobe_context_t	*ctxt = (strobe_context_t *)context;
+
+	if (!ctxt->flash)
+		return;
+
+	ctxt->flash = 0;
+	ctxt->ticks = ticks;
+}
+
+
+static int strobe_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup)
+{
+	const char	*period;
+	const char	*period_values[] = {
+				".0166",
+				".02",
+				".025",
+				".05",
+				".1",
+				".25",
+				".5",
+				"1",
+				NULL
+			};
+	int		r;
+
+	r = til_settings_get_and_describe_value(settings,
+						&(til_setting_desc_t){
+							.name = "Strobe period",
+							.key = "period",
+							.regex = "\\.[0-9]+",
+							.preferred = TIL_SETTINGS_STR(STROBE_DEFAULT_PERIOD),
+							.values = period_values,
+							.annotations = NULL
+						},
+						&period,
+						res_setting,
+						res_desc);
+	if (r)
+		return r;
+
+	if (res_setup) {
+		strobe_setup_t	*setup;
+
+		setup = til_setup_new(sizeof(*setup), (void(*)(til_setup_t *))free);
+		if (!setup)
+			return -ENOMEM;
+
+		sscanf(period, "%f", &setup->period);
+
+		*res_setup = &setup->til_setup;
+	}
+
+	return 0;
+}
+
+
+til_module_t	strobe_module = {
+	.create_context = strobe_create_context,
+	.prepare_frame = strobe_prepare_frame,
+	.render_fragment = strobe_render_fragment,
+	.finish_frame = strobe_finish_frame,
+	.setup = strobe_setup,
+	.name = "strobe",
+	.description = "Strobe light (threaded)",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.flags = TIL_MODULE_OVERLAYABLE,
+};