modules/moire: implement rudimentary moire module

This introduces a very naive unoptimized moire interference
pattern module, it's rather slow complete with a sqrtf() per
pixel per center.

5 files changed, 180 insertions, 2 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 1641711..65b7626 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -3,7 +3,7 @@ SUBDIRS = libs modules
 noinst_LTLIBRARIES = libtil.la
 libtil_la_SOURCES = til_args.c til_args.h til_fb.c til_fb.h til_knobs.h til.c til.h til_module_context.c til_module_context.h til_settings.h til_settings.c til_setup.c til_setup.h til_threads.c til_threads.h til_util.c til_util.h
 libtil_la_CPPFLAGS = -I@top_srcdir@/src
-libtil_la_LIBADD = modules/blinds/libblinds.la modules/checkers/libcheckers.la modules/compose/libcompose.la modules/drizzle/libdrizzle.la modules/flui2d/libflui2d.la modules/julia/libjulia.la modules/meta2d/libmeta2d.la modules/montage/libmontage.la modules/pixbounce/libpixbounce.la modules/plasma/libplasma.la modules/plato/libplato.la modules/ray/libray.la modules/roto/libroto.la modules/rtv/librtv.la modules/shapes/libshapes.la modules/snow/libsnow.la modules/sparkler/libsparkler.la modules/spiro/libspiro.la modules/stars/libstars.la modules/submit/libsubmit.la modules/swab/libswab.la modules/swarm/libswarm.la modules/voronoi/libvoronoi.la libs/grid/libgrid.la libs/puddle/libpuddle.la libs/ray/libray.la libs/sig/libsig.la libs/txt/libtxt.la libs/ascii/libascii.la libs/din/libdin.la
+libtil_la_LIBADD = modules/blinds/libblinds.la modules/checkers/libcheckers.la modules/compose/libcompose.la modules/drizzle/libdrizzle.la modules/flui2d/libflui2d.la modules/julia/libjulia.la modules/meta2d/libmeta2d.la modules/moire/libmoire.la modules/montage/libmontage.la modules/pixbounce/libpixbounce.la modules/plasma/libplasma.la modules/plato/libplato.la modules/ray/libray.la modules/roto/libroto.la modules/rtv/librtv.la modules/shapes/libshapes.la modules/snow/libsnow.la modules/sparkler/libsparkler.la modules/spiro/libspiro.la modules/stars/libstars.la modules/submit/libsubmit.la modules/swab/libswab.la modules/swarm/libswarm.la modules/voronoi/libvoronoi.la libs/grid/libgrid.la libs/puddle/libpuddle.la libs/ray/libray.la libs/sig/libsig.la libs/txt/libtxt.la libs/ascii/libascii.la libs/din/libdin.la
 
 if ENABLE_ROTOTILLER
 bin_PROGRAMS = rototiller
diff --git a/src/modules/Makefile.am b/src/modules/Makefile.am
index d00ac7b..83adbc5 100644
--- a/src/modules/Makefile.am
+++ b/src/modules/Makefile.am
@@ -1 +1 @@
-SUBDIRS = blinds checkers compose drizzle flui2d julia meta2d 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 submit swab swarm voronoi
diff --git a/src/modules/moire/Makefile.am b/src/modules/moire/Makefile.am
new file mode 100644
index 0000000..9d72068
--- /dev/null
+++ b/src/modules/moire/Makefile.am
@@ -0,0 +1,3 @@
+noinst_LTLIBRARIES = libmoire.la
+libmoire_la_SOURCES = moire.c
+libmoire_la_CPPFLAGS = -I@top_srcdir@/src
diff --git a/src/modules/moire/moire.c b/src/modules/moire/moire.c
new file mode 100644
index 0000000..1678170
--- /dev/null
+++ b/src/modules/moire/moire.c
@@ -0,0 +1,173 @@
+/*
+ *  Copyright (C) 2022 - Vito Caputo - <vcaputo@pengaru.com>
+ *
+ *  This program is free software: you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <math.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "til.h"
+#include "til_fb.h"
+#include "til_module_context.h"
+
+#define MOIRE_DEFAULT_CENTERS	2
+
+typedef struct moire_setup_t {
+	til_setup_t	til_setup;
+	unsigned	n_centers;
+} moire_setup_t;
+
+typedef struct moire_center_t {
+	float		x, y;
+	float		seed;
+	float		dir;
+} moire_center_t;
+
+typedef struct moire_context_t {
+	til_module_context_t	til_module_context;
+	moire_setup_t		setup;
+	moire_center_t		centers[];
+} moire_context_t;
+
+static moire_setup_t moire_default_setup = {
+	.n_centers = MOIRE_DEFAULT_CENTERS,
+};
+
+
+static til_module_context_t * moire_create_context(unsigned seed, unsigned ticks, unsigned n_cpus, til_setup_t *setup)
+{
+	moire_context_t	*ctxt;
+
+	if (!setup)
+		setup = &moire_default_setup.til_setup;
+
+	ctxt = til_module_context_new(sizeof(moire_context_t) + ((moire_setup_t *)setup)->n_centers * sizeof(moire_center_t), seed, n_cpus);
+	if (!ctxt)
+		return NULL;
+
+	ctxt->setup = *(moire_setup_t *)setup;
+
+	for (unsigned i = 0; i < ((moire_setup_t *)setup)->n_centers; i++) {
+		ctxt->centers[i].seed = rand_r(&seed) * (1.f / (float)RAND_MAX) * 2 * M_PI;
+		ctxt->centers[i].dir = (rand_r(&seed) * (2.f / (float)RAND_MAX) - 1.f);
+		ctxt->centers[i].x = cosf(ctxt->centers[i].seed + (float)ticks * .001f * ctxt->centers[i].dir);
+		ctxt->centers[i].y = sinf(ctxt->centers[i].seed + (float)ticks * .001f * ctxt->centers[i].dir);
+	}
+
+	return &ctxt->til_module_context;
+}
+
+
+static void moire_prepare_frame(til_module_context_t *context, unsigned ticks, til_fb_fragment_t *fragment, til_fragmenter_t *res_fragmenter)
+{
+	moire_context_t	*ctxt = (moire_context_t *)context;
+
+	*res_fragmenter = til_fragmenter_slice_per_cpu;
+
+	for (unsigned i = 0; i < ctxt->setup.n_centers; i++) {
+		ctxt->centers[i].x = cosf(ctxt->centers[i].seed + (float)ticks * .001f * ctxt->centers[i].dir);
+		ctxt->centers[i].y = sinf(ctxt->centers[i].seed + (float)ticks * .001f * ctxt->centers[i].dir);
+	}
+}
+
+
+static void moire_render_fragment(til_module_context_t *context, unsigned ticks, unsigned cpu, til_fb_fragment_t *fragment)
+{
+	moire_context_t	*ctxt = (moire_context_t *)context;
+	float		xf = 2.f / (float)fragment->frame_width;
+	float		yf = 2.f / (float)fragment->frame_height;
+	float		cx, cy;
+
+	/* TODO: optimize */
+	cy = yf * (float)fragment->y - 1.f;
+	for (int y = fragment->y; y < fragment->y + fragment->height; y++, cy += yf) {
+
+		cx = xf * (float)fragment->x - 1.f;
+		for (int x = fragment->x; x < fragment->x + fragment->width; x++, cx += xf) {
+			int	filled = 0;
+
+			for (unsigned i = 0; i < ctxt->setup.n_centers; i++) {
+				float	dx, dy;
+
+				dx = cx - ctxt->centers[i].x;
+				dy = cy - ctxt->centers[i].y;
+
+				if (cosf(sqrtf(dx * dx + dy * dy) * 50.f) < 0.f)
+					filled ^= 1;
+			}
+
+			if (filled)
+				til_fb_fragment_put_pixel_unchecked(fragment, TIL_FB_DRAW_FLAG_TEXTURABLE, x, y, 0xffffffff);
+			else if (!fragment->cleared)
+				til_fb_fragment_put_pixel_unchecked(fragment, 0, x, y, 0x00000000);
+		}
+	}
+}
+
+
+static int moire_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	*centers;
+	const char	*values[] = {
+				"2",
+				"3",
+				"4",
+				"5",
+				NULL
+			};
+	int		r;
+
+	r = til_settings_get_and_describe_value(settings,
+						&(til_setting_desc_t){
+							.name = "Number of radial centers",
+							.key = "centers",
+							.regex = "\\.[0-9]+",
+							.preferred = TIL_SETTINGS_STR(MOIRE_DEFAULT_CENTERS),
+							.values = values,
+							.annotations = NULL
+						},
+						&centers,
+						res_setting,
+						res_desc);
+	if (r)
+		return r;
+
+	if (res_setup) {
+		moire_setup_t	*setup;
+
+		setup = til_setup_new(sizeof(*setup), (void(*)(til_setup_t *))free);
+		if (!setup)
+			return -ENOMEM;
+
+		sscanf(centers, "%u", &setup->n_centers);
+
+		*res_setup = &setup->til_setup;
+	}
+
+	return 0;
+}
+
+
+til_module_t	moire_module = {
+	.create_context = moire_create_context,
+	.prepare_frame = moire_prepare_frame,
+	.render_fragment = moire_render_fragment,
+	.setup = moire_setup,
+	.name = "moire",
+	.description = "2D Moire interference patterns (threaded)",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.flags = TIL_MODULE_OVERLAYABLE,
+};
diff --git a/src/til.c b/src/til.c
index ff7ce13..b8aecd8 100644
--- a/src/til.c
+++ b/src/til.c
@@ -31,6 +31,7 @@ extern til_module_t	drizzle_module;
 extern til_module_t	flui2d_module;
 extern til_module_t	julia_module;
 extern til_module_t	meta2d_module;
+extern til_module_t	moire_module;
 extern til_module_t	montage_module;
 extern til_module_t	pixbounce_module;
 extern til_module_t	plasma_module;
@@ -56,6 +57,7 @@ static const til_module_t	*modules[] = {
 	&flui2d_module,
 	&julia_module,
 	&meta2d_module,
+	&moire_module,
 	&montage_module,
 	&pixbounce_module,
 	&plasma_module,