modules/signals: experimental signals module

Playing with libs/sig in 2D, this isn't really an interesting
module by itself in terms of visual output.  But it might have
utility as a diagnostic thing if libs/sig becomes a more used
thing.

At the very least, for now, it's useful for observing affects of
and iterating on libs/sig development.  So I'm merging this, just
gated behind TIL_MODULE_EXPERIMENTAL so it's not in rtv rotation
or presented as something in the usual modules list.

2 files changed, 202 insertions, 0 deletions

diff --git a/src/modules/signals/Makefile.am b/src/modules/signals/Makefile.am
new file mode 100644
index 0000000..0bfe4df
--- /dev/null
+++ b/src/modules/signals/Makefile.am
@@ -0,0 +1,3 @@
+noinst_LTLIBRARIES = libsignals.la
+libsignals_la_SOURCES = signals.c
+libsignals_la_CPPFLAGS = -I@top_srcdir@/src -I@top_srcdir@/src/libs
diff --git a/src/modules/signals/signals.c b/src/modules/signals/signals.c
new file mode 100644
index 0000000..c56c6f8
--- /dev/null
+++ b/src/modules/signals/signals.c
@@ -0,0 +1,199 @@
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "til.h"
+#include "til_fb.h"
+#include "til_module_context.h"
+
+#include "sig/sig.h"
+
+/* Copyright (C) 2020-2022 - Vito Caputo <vcaputo@pengaru.com> */
+
+/* 2D waveform drawings to exercise libs/sig and explore its ergonomics */
+
+/* TODO: a tileable mode would be neat, where the start and end
+ * heights always match up for the lines...
+ *
+ * TODO: a connected-lines version would be neat as well
+ *
+ * TODO: exposing taps for influencing the signals could be fun
+ * too, as well as making N_SIGNALS a runtime setting.
+ */
+
+#define N_SIGNALS	11
+
+typedef struct signals_context_t {
+	til_module_context_t	til_module_context;
+	sig_sig_t		*signals[N_SIGNALS];
+} signals_context_t;
+
+
+static til_module_context_t * signals_create_context(const til_module_t *module, til_stream_t *stream, unsigned seed, unsigned ticks, unsigned n_cpus, til_setup_t *setup)
+{
+	signals_context_t	*ctxt;
+
+	ctxt = til_module_context_new(module, sizeof(signals_context_t), stream, seed, ticks, n_cpus, setup);
+	if (!ctxt)
+		return NULL;
+
+	ctxt->signals[0] = sig_new_sin(sig_new_const(.5f));			/* oscillate @ .5hz */
+	if (!ctxt->signals[0])
+		goto err;
+
+	ctxt->signals[1] =	sig_new_sin(					/* oscillate */
+					sig_new_scale(				/* at a scaled frequency */
+						sig_new_sin(sig_new_const(.1f)),/* from another oscillator @ .1hz */
+						sig_new_const(.2f),		/* from .2 */
+						sig_new_const(7.f)		/* to 7 */
+					)
+				);
+	if (!ctxt->signals[1])
+		goto err;
+
+	ctxt->signals[2] =	sig_new_lerp(					/* interpolate */
+					sig_new_sin(sig_new_const(.33f)),	/* a .33hz oscillator */
+					sig_new_sin(sig_new_const(.15f)),	/* and a .15hz oscillator */
+					sig_new_sin(sig_new_const(2.f))		/* weighted by a 2hz oscillator */
+				);
+	if (!ctxt->signals[2])
+		goto err;
+
+	ctxt->signals[3] =	sig_new_pow(	       				/* raise */
+					sig_new_sin(sig_new_const(4.f)),	/* a 4hz oscillator */
+					sig_new_sin(sig_new_const(.33f))	/* to the power of a .33f hz oscillator */
+				);
+	if (!ctxt->signals[3])
+		goto err;
+
+	ctxt->signals[4] =	sig_new_mult(	       		       		/* multiply */
+					sig_new_sin(sig_new_const(4.f)),	/* a 4hz oscillator */
+					sig_new_sin(sig_new_const(1.f))		/* by a 1hz oscillator */
+				);
+	if (!ctxt->signals[4])
+		goto err;
+
+	ctxt->signals[5] =	sig_new_lerp(					/* interpolate */
+					sig_ref(ctxt->signals[3]),		/* signals[3] */
+					sig_ref(ctxt->signals[4]),		/* signals[4] */
+					sig_ref(ctxt->signals[2])		/* weighted by signals[2] */
+				);
+	if (!ctxt->signals[5])
+		goto err;
+
+	ctxt->signals[6] =	sig_new_lerp(					/* interpolate */
+					sig_new_inv(sig_ref(ctxt->signals[5])),	/* invert of signals[5] */
+					sig_new_pow(sig_ref(ctxt->signals[5]),	/* with raised signals[5] */
+						sig_ref(ctxt->signals[3])),	/* to power of signals[3] */
+					sig_ref(ctxt->signals[2])		/* weighted by signals[2] */
+				);
+	if (!ctxt->signals[6])
+		goto err;
+
+	ctxt->signals[7] =	sig_new_mult(					/* multiply */
+					sig_ref(ctxt->signals[6]),		/* signals[6] */
+					sig_ref(ctxt->signals[5])		/* signals[5] */
+				);
+	if (!ctxt->signals[7])
+		goto err;
+
+	ctxt->signals[8] =	sig_new_mult(					/* multiply */
+					sig_ref(ctxt->signals[1]),		/* signals[1] */
+					sig_ref(ctxt->signals[7])		/* signals[7] */
+				);
+	if (!ctxt->signals[8])
+		goto err;
+
+	ctxt->signals[9] =	sig_new_pow(					/* raise */
+					sig_ref(ctxt->signals[3]),		/* signals[3] */
+					sig_new_scale(				/* to power of scaled */
+						sig_ref(ctxt->signals[7]),	/* signals[7] */
+						sig_new_const(.1f),		/* into range .1f .. */
+						sig_new_const(20.f)		/* to 20.f */
+					)
+				);
+	if (!ctxt->signals[9])
+		goto err;
+
+	ctxt->signals[10] =	sig_new_lerp(					/* interpolate */
+					sig_ref(ctxt->signals[9]),		/* signals[9] */
+					sig_new_rand(),				/* random noise */
+					sig_new_lerp(				/* weighted by interpolating */
+						sig_new_inv(			/* inverted ... */
+							sig_ref(ctxt->signals[5])),/* signals[5] */
+						sig_ref(ctxt->signals[3]),	/* and signals[3] */
+						sig_ref(ctxt->signals[1])	/* weighted by signals[1] */
+					)
+				);
+	if (!ctxt->signals[10])
+		goto err;
+
+	return &ctxt->til_module_context;
+
+err:
+	for (unsigned i = 0; i < N_SIGNALS; i++)
+		sig_free(ctxt->signals[i]);
+
+	free(ctxt);
+
+	return NULL;
+}
+
+
+static void signals_destroy_context(til_module_context_t *context)
+{
+	signals_context_t	*ctxt = (signals_context_t *)context;
+
+	for (unsigned i = 0; i < N_SIGNALS; i++)
+		sig_free(ctxt->signals[i]);
+
+	free(ctxt);
+}
+
+
+static int signals_fragmenter(til_module_context_t *context, const til_fb_fragment_t *fragment, unsigned number, til_fb_fragment_t *res_fragment)
+{
+	return til_fb_fragment_slice_single(fragment, N_SIGNALS, number, res_fragment);
+}
+
+
+static void signals_prepare_frame(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr, til_frame_plan_t *res_frame_plan)
+{
+	*res_frame_plan = (til_frame_plan_t){ .fragmenter = signals_fragmenter };
+}
+
+
+static void signals_render_fragment(til_module_context_t *context, til_stream_t *stream, unsigned ticks, unsigned cpu, til_fb_fragment_t **fragment_ptr)
+{
+	signals_context_t	*ctxt = (signals_context_t *)context;
+	til_fb_fragment_t	*fragment = *fragment_ptr;
+
+	til_fb_fragment_clear(fragment);
+
+	if (fragment->number >= N_SIGNALS)
+		return;
+
+	ticks >>= 2;	/* move a bit slower */
+
+	for (unsigned x = 0, y; x < fragment->width; x++) {
+		float	size = fragment->height - 1;
+
+		/* This needs to compute an offset into fragment->height,
+		 * from a 0-1 range, hence size is height - 1 to not overflow.
+		 */
+		y = size - sig_output(ctxt->signals[fragment->number], ticks + x) * size;
+
+		til_fb_fragment_put_pixel_checked(fragment, TIL_FB_DRAW_FLAG_TEXTURABLE, fragment->x + x, fragment->y + y, 0xffffffff);
+	}
+}
+
+
+til_module_t	signals_module = {
+	.create_context = signals_create_context,
+	.destroy_context = signals_destroy_context,
+	.prepare_frame = signals_prepare_frame,
+	.render_fragment = signals_render_fragment,
+	.name = "signals",
+	.description = "2D Waveforms (threaded)",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.flags = TIL_MODULE_OVERLAYABLE | TIL_MODULE_EXPERIMENTAL,
+};