modules/drizzle: add a classic 2D raindrops vis

Using the new puddle lib throw some raindrops on the framebuffer

2 files changed, 200 insertions, 0 deletions

diff --git a/src/modules/drizzle/Makefile.am b/src/modules/drizzle/Makefile.am
new file mode 100644
index 0000000..caaa45f
--- /dev/null
+++ b/src/modules/drizzle/Makefile.am
@@ -0,0 +1,3 @@
+noinst_LIBRARIES = libdrizzle.a
+libdrizzle_a_SOURCES = drizzle.c
+libdrizzle_a_CPPFLAGS = -I@top_srcdir@/src -I@top_srcdir@/src/libs
diff --git a/src/modules/drizzle/drizzle.c b/src/modules/drizzle/drizzle.c
new file mode 100644
index 0000000..436c347
--- /dev/null
+++ b/src/modules/drizzle/drizzle.c
@@ -0,0 +1,197 @@
+/*
+ *  Copyright (C) 2020 - 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 3 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 <stdlib.h>
+#include <unistd.h>
+
+#include "fb.h"
+#include "puddle/puddle.h"
+#include "rototiller.h"
+
+#define PUDDLE_SIZE		512
+#define DRIZZLE_CNT		20
+#define DEFAULT_VISCOSITY	.01f
+
+typedef struct drizzle_context_t {
+	puddle_t	*puddle;
+	unsigned	n_cpus;
+} drizzle_context_t;
+
+typedef struct v3f_t {
+	float	x, y, z;
+} v3f_t;
+
+typedef struct v2f_t {
+	float	x, y;
+} v2f_t;
+
+static float	drizzle_viscosity = DEFAULT_VISCOSITY;
+
+
+/* convert a color into a packed, 32-bit rgb pixel value (taken from libs/ray/ray_color.h) */
+static inline uint32_t color_to_uint32(v3f_t color) {
+	uint32_t	pixel;
+
+	if (color.x > 1.0f) color.x = 1.0f;
+	if (color.y > 1.0f) color.y = 1.0f;
+	if (color.z > 1.0f) color.z = 1.0f;
+
+	if (color.x < .0f) color.x = .0f;
+	if (color.y < .0f) color.y = .0f;
+	if (color.z < .0f) color.z = .0f;
+
+	pixel = (uint32_t)(color.x * 255.0f);
+	pixel <<= 8;
+	pixel |= (uint32_t)(color.y * 255.0f);
+	pixel <<= 8;
+	pixel |= (uint32_t)(color.z * 255.0f);
+
+	return pixel;
+}
+
+
+static void * drizzle_create_context(unsigned num_cpus)
+{
+	drizzle_context_t	*ctxt;
+
+	ctxt = calloc(1, sizeof(drizzle_context_t));
+	if (!ctxt)
+		return NULL;
+
+	ctxt->puddle = puddle_new(PUDDLE_SIZE, PUDDLE_SIZE);
+	if (!ctxt->puddle) {
+		free(ctxt);
+		return NULL;
+	}
+
+	ctxt->n_cpus = num_cpus;
+
+	return ctxt;
+}
+
+
+static void drizzle_destroy_context(void *context)
+{
+	drizzle_context_t	*ctxt = context;
+
+	puddle_free(ctxt->puddle);
+	free(ctxt);
+}
+
+
+static int drizzle_fragmenter(void *context, const fb_fragment_t *fragment, unsigned number, fb_fragment_t *res_fragment)
+{
+	drizzle_context_t	*ctxt = context;
+
+	return fb_fragment_slice_single(fragment, ctxt->n_cpus, number, res_fragment);
+}
+
+
+static void drizzle_prepare_frame(void *context, unsigned n_cpus, fb_fragment_t *fragment, rototiller_fragmenter_t *res_fragmenter)
+{
+	drizzle_context_t	*ctxt = context;
+
+	*res_fragmenter = drizzle_fragmenter;
+
+	for (int i = 0; i < DRIZZLE_CNT; i++) {
+		int	x = rand() % (PUDDLE_SIZE - 1);
+		int	y = rand() % (PUDDLE_SIZE - 1);
+
+		/* TODO: puddle should probably offer a normalized way of setting an
+		 * area to a value, so if PUDDLE_SIZE changes this automatically
+		 * would adapt to cover the same portion of the unit square...
+		 */
+		puddle_set(ctxt->puddle, x, y, 1.f);
+		puddle_set(ctxt->puddle, x + 1, y, 1.f);
+		puddle_set(ctxt->puddle, x, y + 1, 1.f);
+		puddle_set(ctxt->puddle, x + 1, y + 1, 1.f);
+	}
+
+	puddle_tick(ctxt->puddle, drizzle_viscosity);
+}
+
+
+static void drizzle_render_fragment(void *context, unsigned cpu, fb_fragment_t *fragment)
+{
+	drizzle_context_t	*ctxt = context;
+	float			xf = 2.f / (float)fragment->frame_width;
+	float			yf = 2.f / (float)fragment->frame_height;
+	v2f_t			coord;
+
+	for (int y = fragment->y; y < fragment->y + fragment->height; y++) {
+		coord.y = yf * (float)y - 1.f;
+
+		for (int x = fragment->x; x < fragment->x + fragment->width; x++) {
+			v3f_t		color = {};
+			uint32_t	pixel;
+
+			coord.x = xf * (float)x - 1.f;
+
+			color.z = puddle_sample(ctxt->puddle, &coord);
+
+			pixel = color_to_uint32(color);
+			fb_fragment_put_pixel_unchecked(fragment, x, y, pixel);
+		}
+	}
+}
+
+
+static int drizzle_setup(const settings_t *settings, setting_desc_t **next_setting)
+{
+	const char	*viscosity;
+	const char	*values[] = {
+				".005f",
+				".01f",
+				".03f",
+				".05f",
+				NULL
+			};
+
+	viscosity = settings_get_value(settings, "viscosity");
+	if (!viscosity) {
+		int	r;
+
+		r = setting_desc_clone(&(setting_desc_t){
+						.name = "Puddle Viscosity",
+						.key = "viscosity",
+						.regex = "\\.[0-9]+",
+						.preferred = SETTINGS_STR(DEFAULT_VISCOSITY),
+						.values = values,
+						.annotations = NULL
+					}, next_setting);
+		if (r < 0)
+			return r;
+
+		return 1;
+	}
+
+	sscanf(viscosity, "%f", &drizzle_viscosity);
+
+	return 0;
+}
+
+
+rototiller_module_t	drizzle_module = {
+	.create_context = drizzle_create_context,
+	.destroy_context = drizzle_destroy_context,
+	.prepare_frame = drizzle_prepare_frame,
+	.render_fragment = drizzle_render_fragment,
+	.name = "drizzle",
+	.description = "Classic 2D rain effect (threaded (poorly))",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.license = "GPLv3",
+	.setup = drizzle_setup,
+};