meta2d: add a classic 2D metaballs module

4 files changed, 946 insertions, 0 deletions

diff --git a/src/modules/meta2d/Makefile.am b/src/modules/meta2d/Makefile.am
new file mode 100644
index 0000000..b1394d1
--- /dev/null
+++ b/src/modules/meta2d/Makefile.am
@@ -0,0 +1,3 @@
+noinst_LIBRARIES = libmeta2d.a
+libmeta2d_a_SOURCES = meta2d.c v2f.h v3f.h
+libmeta2d_a_CPPFLAGS = -I@top_srcdir@/src -I@top_srcdir@/src/libs
diff --git a/src/modules/meta2d/meta2d.c b/src/modules/meta2d/meta2d.c
new file mode 100644
index 0000000..08cd15a
--- /dev/null
+++ b/src/modules/meta2d/meta2d.c
@@ -0,0 +1,235 @@
+/*
+ *  Copyright (C) 2019 - 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/>.
+ */
+
+/* https://en.wikipedia.org/wiki/Metaballs */
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "din/din.h"
+#include "fb.h"
+#include "rototiller.h"
+
+#include "v2f.h"
+#include "v3f.h"
+
+#define	META2D_NUM_BALLS	10
+
+typedef struct meta2d_ball_t {
+	v2f_t		position;
+	float		radius;
+	v3f_t		color;
+} meta2d_ball_t;
+
+typedef struct meta2d_context_t {
+	unsigned	n;
+	din_t		*din_a, *din_b;
+	float		din_t;
+	unsigned	n_cpus;
+	meta2d_ball_t	balls[META2D_NUM_BALLS];
+} meta2d_context_t;
+
+
+/* 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 * meta2d_create_context(unsigned num_cpus)
+{
+	meta2d_context_t	*ctxt;
+
+	ctxt = calloc(1, sizeof(meta2d_context_t));
+
+	/* perlin noise is used for some organic-ish random movement of the balls */
+	ctxt->din_a = din_new(10, 10, META2D_NUM_BALLS + 2);
+	ctxt->din_b = din_new(10, 10, META2D_NUM_BALLS + 2);
+
+	srand(getpid());
+	ctxt->n_cpus = num_cpus;
+
+	for (int i = 0; i < META2D_NUM_BALLS; i++) {
+		meta2d_ball_t	*ball = &ctxt->balls[i];
+
+		v2f_rand(&ball->position, &(v2f_t){-.7f, -.7f}, &(v2f_t){.7f, .7f});
+		ball->radius = rand() / (float)RAND_MAX * .2f + .05f;
+		v3f_rand(&ball->color, &(v3f_t){0.f, 0.f, 0.f}, &(v3f_t){1.f, 1.f, 1.f});
+	}
+
+	return ctxt;
+}
+
+
+static void meta2d_destroy_context(void *context)
+{
+	meta2d_context_t	*ctxt = context;
+
+	din_free(ctxt->din_a);
+	din_free(ctxt->din_b);
+	free(ctxt);
+}
+
+
+static int meta2d_fragmenter(void *context, const fb_fragment_t *fragment, unsigned number, fb_fragment_t *res_fragment)
+{
+	meta2d_context_t	*ctxt = context;
+
+	return fb_fragment_slice_single(fragment, ctxt->n_cpus, number, res_fragment);
+}
+
+
+static void meta2d_prepare_frame(void *context, unsigned n_cpus, fb_fragment_t *fragment, rototiller_fragmenter_t *res_fragmenter)
+{
+	meta2d_context_t	*ctxt = context;
+
+	*res_fragmenter = meta2d_fragmenter;
+
+	/* move the balls around */
+	for (int i = 0; i < META2D_NUM_BALLS; i++) {
+		meta2d_ball_t	*ball = &ctxt->balls[i];
+		float		rad;
+
+		/* Perlin noise indexed by position for x,y and i for z
+		 * is used just for moving the metaballs around.
+		 *
+		 * Two noise fields are used with their values interpolated,
+		 * starting with the din_a being 100% of the movement,
+		 * with every frame migrating closer to din_b being 100%.
+		 *
+		 * Once din_b contributes 100%, it becomes din_a, and the old
+		 * din_a becomes din_b which gets randomized, and the % resets
+		 * to 0.
+		 *
+		 * This allows an organic continuous evolution of the field
+		 * over time, at double the sampling cost since we're sampling
+		 * two noise fields and interpolating them.  Since this is
+		 * just per-ball every frame, it's probably OK.  Not like it's
+		 * every pixel.
+		 */
+
+		/* ad-hoc lerp of the two dins */
+		rad = din(ctxt->din_a, &(v3f_t){
+			  .x = ball->position.x,
+			  .y = ball->position.y,
+			  .z = (float)i * (1.f / (float)META2D_NUM_BALLS)}
+			 ) * (1.f - ctxt->din_t);
+
+		rad += din(ctxt->din_b, &(v3f_t){
+			  .x = ball->position.x,
+			  .y = ball->position.y,
+			  .z = (float)i * (1.f / (float)META2D_NUM_BALLS)}
+			 ) * ctxt->din_t;
+
+		/* Perlin noise doesn't produce anything close to a uniform random distribution
+		 * of -1..+1, so it can't just be mapped directly to 2*PI with all angles getting
+		 * roughly equal occurrences in the long-run.  For now I just *10.f and it seems
+		 * to be OK.
+		 */
+		rad *= 10.f * 2.f * M_PI;
+		v2f_add(&ball->position,
+			&ball->position,
+			&(v2f_t){
+				.x = cosf(rad) * .003f,	/* small steps */
+				.y = sinf(rad) * .003f,
+			});
+
+		v2f_clamp(&ball->position,
+			  &ball->position,
+			  &(v2f_t){-.8f, -.8f},	/* keep the balls mostly on-screen */
+			  &(v2f_t){.8f, .8f}
+			);
+	}
+
+	/* when din_t reaches 1 swap a<->b, reset din_t, randomize b */
+	ctxt->din_t += .01f;
+	if (ctxt->din_t >= 1.f) {
+		din_t	*tmp;
+
+		tmp = ctxt->din_a;
+		ctxt->din_a = ctxt->din_b;
+		ctxt->din_b = tmp;
+
+		din_randomize(ctxt->din_b);
+		ctxt->din_t = 0.f;
+	}
+}
+
+
+static void meta2d_render_fragment(void *context, unsigned cpu, fb_fragment_t *fragment)
+{
+	meta2d_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;
+			float		t = 0;
+
+			coord.x = xf * (float)x - 1.f;
+
+			for (int i = 0; i < META2D_NUM_BALLS; i++) {
+				meta2d_ball_t	*ball = &ctxt->balls[i];
+
+				float	f;
+
+				f = ball->radius * ball->radius / v2f_distance_sq(&coord, &ball->position);
+				v3f_add(&color, &color, v3f_mult_scalar(&(v3f_t){}, &ball->color, f));
+				t += f;
+			}
+
+			/* these thresholds define the thickness of the ribbon */
+			if (t < .7f || t > .8f)
+				color = (v3f_t){};
+
+			pixel = color_to_uint32(color);
+			fb_fragment_put_pixel_unchecked(fragment, x, y, pixel);
+		}
+	}
+}
+
+
+rototiller_module_t	meta2d_module = {
+	.create_context = meta2d_create_context,
+	.destroy_context = meta2d_destroy_context,
+	.prepare_frame = meta2d_prepare_frame,
+	.render_fragment = meta2d_render_fragment,
+	.name = "meta2d",
+	.description = "Classic 2D metaballs (threaded)",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.license = "GPLv3",
+};
diff --git a/src/modules/meta2d/v2f.h b/src/modules/meta2d/v2f.h
new file mode 100644
index 0000000..8f51ee0
--- /dev/null
+++ b/src/modules/meta2d/v2f.h
@@ -0,0 +1,352 @@
+/*
+ *  Copyright (C) 2018-2019 - 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/>.
+ */
+
+/*
+ * 2D vector operations header
+ *
+ * Variants prefixed with _ return a result vector struct by value.
+ *
+ * Variants missing the _ prefix for vector result operations return a pointer
+ * and must be either supplied the result memory as the first "res" argument
+ * which is then returned after being populated with the result's value, or
+ * NULL to allocate space for the result and that pointer is returned after being
+ * populated with its value.  When supplying NULL result pointers the functions
+ * must allocate memory and thus may return NULL on OOM, so callers should
+ * check for NULL returns when supplying NULL for "res".
+ *
+ * Example:
+ *	v2f_t	foo, *foop;
+ *
+ *	foo = _v2f_mult(&(v2f_t){1.f,1.f}, &(v2f_t){2.f,2.f});
+ *
+ *	is equivalent to:
+ *
+ *	v2f_mult(&foo, &(v2f_t){1.f,1.f}, &(v2f_t){2.f,2.f});
+ *
+ *	or dynamically allocated:
+ *
+ *	foop = v2f_mult(NULL, &(v2f_t){1.f,1.f}, &(v2f_t){2.f,2.f});
+ *	free(foop);
+ *
+ *	is equivalent to:
+ *
+ *	foop = malloc(sizeof(v2f_t));
+ *	v2f_mult(foop, &(v2f_t){1.f,1.f}, &(v2f_t){2.f,2.f});
+ *	free(foop);
+ */
+
+#ifndef _V2F_H
+#define _V2F_H
+
+
+#include <math.h>
+#include <stdlib.h>
+
+
+typedef struct v2f_t {
+	float	x, y;
+} v2f_t;
+
+
+static inline v2f_t * _v2f_allocated(v2f_t **ptr)
+{
+	if (!*ptr)
+		*ptr = malloc(sizeof(v2f_t));
+
+	return *ptr;
+}
+
+
+static inline v2f_t _v2f_add(const v2f_t *a, const v2f_t *b)
+{
+	return (v2f_t){a->x + b->x, a->y + b->y};
+}
+
+
+static inline v2f_t * v2f_add(v2f_t *res, const v2f_t *a, const v2f_t *b)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_add(a, b);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_sub(const v2f_t *a, const v2f_t *b)
+{
+	return (v2f_t){a->x - b->x, a->y - b->y};
+}
+
+
+static inline v2f_t * v2f_sub(v2f_t *res, const v2f_t *a, const v2f_t *b)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_sub(a, b);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_mult(const v2f_t *a, const v2f_t *b)
+{
+	return (v2f_t){a->x * b->x, a->y * b->y};
+}
+
+
+static inline v2f_t * v2f_mult(v2f_t *res, const v2f_t *a, const v2f_t *b)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_mult(a, b);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_mult_scalar(const v2f_t *v, float scalar)
+{
+	return (v2f_t){ v->x * scalar, v->y * scalar };
+}
+
+
+static inline v2f_t * v2f_mult_scalar(v2f_t *res, const v2f_t *v, float scalar)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_mult_scalar(v, scalar);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_div_scalar(const v2f_t *v, float scalar)
+{
+	return _v2f_mult_scalar(v, 1.f / scalar);
+}
+
+
+static inline v2f_t * v2f_div_scalar(v2f_t *res, const v2f_t *v, float scalar)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_div_scalar(v, scalar);
+
+	return res;
+}
+
+
+static inline float v2f_dot(const v2f_t *a, const v2f_t *b)
+{
+	return a->x * b->x + a->y * b->y;
+}
+
+
+static inline float v2f_length(const v2f_t *v)
+{
+	return sqrtf(v2f_dot(v, v));
+}
+
+
+static inline float v2f_distance(const v2f_t *a, const v2f_t *b)
+{
+	return v2f_length(v2f_sub(&(v2f_t){}, a, b));
+}
+
+
+static inline float v2f_distance_sq(const v2f_t *a, const v2f_t *b)
+{
+	v2f_t	d = _v2f_sub(a, b);
+
+	return v2f_dot(&d, &d);
+}
+
+
+static inline v2f_t _v2f_normalize(const v2f_t *v)
+{
+	return _v2f_mult_scalar(v, 1.0f / v2f_length(v));
+}
+
+
+static inline v2f_t * v2f_normalize(v2f_t *res, const v2f_t *v)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_normalize(v);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_lerp(const v2f_t *a, const v2f_t *b, float t)
+{
+	v2f_t	lerp_a, lerp_b;
+
+	lerp_a = _v2f_mult_scalar(a, 1.0f - t);
+	lerp_b = _v2f_mult_scalar(b, t);
+
+	return _v2f_add(&lerp_a, &lerp_b);
+}
+
+
+static inline v2f_t * v2f_lerp(v2f_t *res, const v2f_t *a, const v2f_t *b, float t)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_lerp(a, b, t);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_nlerp(const v2f_t *a, const v2f_t *b, float t)
+{
+	v2f_t	lerp = _v2f_lerp(a, b, t);
+
+	return _v2f_normalize(&lerp);
+}
+
+
+static inline v2f_t * v2f_nlerp(v2f_t *res, const v2f_t *a, const v2f_t *b, float t)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_nlerp(a, b, t);
+
+	return res;
+}
+
+
+/*
+ *       1 ab-------bb
+ *       | |         |
+ *       | |         |
+ *       | |         |
+ *       0 aa-------ba
+ *  t_x:   0---------1
+ *       ^
+ *       t_y
+ */
+static inline v2f_t _v2f_bilerp(const v2f_t *aa, const v2f_t *ab, const v2f_t *ba, const v2f_t *bb, float t_x, float t_y)
+{
+	v2f_t	xa = _v2f_lerp(aa, ba, t_x);
+	v2f_t	xb = _v2f_lerp(ab, bb, t_x);
+
+	return _v2f_lerp(&xa, &xb, t_y);
+}
+
+
+static inline v2f_t * v2f_bilerp(v2f_t *res, const v2f_t *aa, const v2f_t *ab, const v2f_t *ba, const v2f_t *bb, float t_x, float t_y)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_bilerp(aa, ab, ba, bb, t_x, t_y);
+
+	return res;
+}
+
+
+/*
+ *     abb-------bbb
+ *     /|        /|
+ *   aba-------bba|
+ *    | |       | |
+ *    |aab------|bab
+ *    |/        |/
+ *   aaa-------baa
+ */
+static inline v2f_t _v2f_trilerp(const v2f_t *aaa, const v2f_t *aba, const v2f_t *aab, const v2f_t *abb, const v2f_t *baa, const v2f_t *bba, const v2f_t *bab, const v2f_t *bbb, float t_x, float t_y, float t_z)
+{
+	v2f_t	xya = _v2f_bilerp(aaa, aba, baa, bba, t_x, t_y);
+	v2f_t	xyb = _v2f_bilerp(aab, abb, bab, bbb, t_x, t_y);
+
+	return _v2f_lerp(&xya, &xyb, t_z);
+}
+
+
+static inline v2f_t * v2f_trilerp(v2f_t *res, const v2f_t *aaa, const v2f_t *aba, const v2f_t *aab, const v2f_t *abb, const v2f_t *baa, const v2f_t *bba, const v2f_t *bab, const v2f_t *bbb, float t_x, float t_y, float t_z)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_trilerp(aaa, aba, aab, abb, baa, bba, bab, bbb, t_x, t_y, t_z);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_rand(const v2f_t *min, const v2f_t *max)
+{
+	return (v2f_t){
+		.x = min->x + (float)rand() * (1.f/RAND_MAX) * (max->x - min->x),
+		.y = min->y + (float)rand() * (1.f/RAND_MAX) * (max->y - min->y),
+	};
+}
+
+
+static inline v2f_t * v2f_rand(v2f_t *res, const v2f_t *min, const v2f_t *max)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_rand(min, max);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_ceil(const v2f_t *v)
+{
+	return (v2f_t){
+		.x = ceilf(v->x),
+		.y = ceilf(v->y),
+	};
+}
+
+
+static inline v2f_t * v2f_ceil(v2f_t *res, const v2f_t *v)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_ceil(v);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_floor(const v2f_t *v)
+{
+	return (v2f_t){
+		.x = floorf(v->x),
+		.y = floorf(v->y),
+	};
+}
+
+
+static inline v2f_t * v2f_floor(v2f_t *res, const v2f_t *v)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_floor(v);
+
+	return res;
+}
+
+
+static inline v2f_t _v2f_clamp(const v2f_t *v, const v2f_t *min, const v2f_t *max)
+{
+	return (v2f_t){
+		.x = v->x < min->x ? min->x : v->x > max->x ? max->x : v->x,
+		.y = v->y < min->y ? min->y : v->y > max->y ? max->y : v->y,
+	};
+}
+
+
+static inline v2f_t * v2f_clamp(v2f_t *res, const v2f_t *v, const v2f_t *min, const v2f_t *max)
+{
+	if (_v2f_allocated(&res))
+		*res = _v2f_clamp(v, min, max);
+
+	return res;
+}
+
+#endif
diff --git a/src/modules/meta2d/v3f.h b/src/modules/meta2d/v3f.h
new file mode 100644
index 0000000..79aea72
--- /dev/null
+++ b/src/modules/meta2d/v3f.h
@@ -0,0 +1,356 @@
+/*
+ *  Copyright (C) 2018-2019 - 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/>.
+ */
+
+/*
+ * 3D vector operations header
+ *
+ * Variants prefixed with _ return a result vector struct by value.
+ *
+ * Variants missing the _ prefix for vector result operations return a pointer
+ * and must be either supplied the result memory as the first "res" argument
+ * which is then returned after being populated with the result's value, or
+ * NULL to allocate space for the result and that pointer is returned after being
+ * populated with its value.  When supplying NULL result pointers the functions
+ * must allocate memory and thus may return NULL on OOM, so callers should
+ * check for NULL returns when supplying NULL for "res".
+ *
+ * Example:
+ *	v3f_t	foo, *foop;
+ *
+ *	foo = _v3f_mult(&(v3f_t){1.f,1.f,1.f}, &(v3f_t){2.f,2.f,2.f});
+ *
+ *	is equivalent to:
+ *
+ *	v3f_mult(&foo, &(v3f_t){1.f,1.f,1.f}, &(v3f_t){2.f,2.f,2.f});
+ *
+ *	or dynamically allocated:
+ *
+ *	foop = v3f_mult(NULL, &(v3f_t){1.f,1.f,1.f}, &(v3f_t){2.f,2.f,2.f});
+ *	free(foop);
+ *
+ *	is equivalent to:
+ *
+ *	foop = malloc(sizeof(v3f_t));
+ *	v3f_mult(foop, &(v3f_t){1.f,1.f,1.f}, &(v3f_t){2.f,2.f,2.f});
+ *	free(foop);
+ */
+
+#ifndef _V3F_H
+#define _V3F_H
+
+
+#include <math.h>
+#include <stdlib.h>
+
+
+typedef struct v3f_t {
+	float	x, y, z;
+} v3f_t;
+
+
+static inline v3f_t * _v3f_allocated(v3f_t **ptr)
+{
+	if (!*ptr)
+		*ptr = malloc(sizeof(v3f_t));
+
+	return *ptr;
+}
+
+
+static inline v3f_t _v3f_add(const v3f_t *a, const v3f_t *b)
+{
+	return (v3f_t){a->x + b->x, a->y + b->y, a->z + b->z};
+}
+
+
+static inline v3f_t * v3f_add(v3f_t *res, const v3f_t *a, const v3f_t *b)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_add(a, b);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_sub(const v3f_t *a, const v3f_t *b)
+{
+	return (v3f_t){a->x - b->x, a->y - b->y, a->z - b->z};
+}
+
+
+static inline v3f_t * v3f_sub(v3f_t *res, const v3f_t *a, const v3f_t *b)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_sub(a, b);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_mult(const v3f_t *a, const v3f_t *b)
+{
+	return (v3f_t){a->x * b->x, a->y * b->y, a->z * b->z};
+}
+
+
+static inline v3f_t * v3f_mult(v3f_t *res, const v3f_t *a, const v3f_t *b)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_mult(a, b);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_mult_scalar(const v3f_t *v, float scalar)
+{
+	return (v3f_t){v->x * scalar, v->y * scalar, v->z * scalar};
+}
+
+
+static inline v3f_t * v3f_mult_scalar(v3f_t *res, const v3f_t *v, float scalar)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_mult_scalar(v, scalar);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_div_scalar(const v3f_t *v, float scalar)
+{
+	return _v3f_mult_scalar(v, 1.f / scalar);
+}
+
+
+static inline v3f_t * v3f_div_scalar(v3f_t *res, const v3f_t *v, float scalar)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_div_scalar(v, scalar);
+
+	return res;
+}
+
+
+static inline float v3f_dot(const v3f_t *a, const v3f_t *b)
+{
+	return a->x * b->x + a->y * b->y + a->z * b->z;
+}
+
+
+static inline float v3f_length(const v3f_t *v)
+{
+	return sqrtf(v3f_dot(v, v));
+}
+
+
+static inline float v3f_distance(const v3f_t *a, const v3f_t *b)
+{
+	return v3f_length(v3f_sub(&(v3f_t){}, a, b));
+}
+
+
+static inline float v3f_distance_sq(const v3f_t *a, const v3f_t *b)
+{
+	v3f_t	d = _v3f_sub(a, b);
+
+	return v3f_dot(&d, &d);
+}
+
+
+static inline v3f_t _v3f_normalize(const v3f_t *v)
+{
+	return _v3f_mult_scalar(v, 1.0f / v3f_length(v));
+}
+
+
+static inline v3f_t * v3f_normalize(v3f_t *res, const v3f_t *v)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_normalize(v);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_lerp(const v3f_t *a, const v3f_t *b, float t)
+{
+	v3f_t	lerp_a, lerp_b;
+
+	lerp_a = _v3f_mult_scalar(a, 1.0f - t);
+	lerp_b = _v3f_mult_scalar(b, t);
+
+	return _v3f_add(&lerp_a, &lerp_b);
+}
+
+
+static inline v3f_t * v3f_lerp(v3f_t *res, const v3f_t *a, const v3f_t *b, float t)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_lerp(a, b, t);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_nlerp(const v3f_t *a, const v3f_t *b, float t)
+{
+	v3f_t	lerp = _v3f_lerp(a, b, t);
+
+	return _v3f_normalize(&lerp);
+}
+
+
+static inline v3f_t * v3f_nlerp(v3f_t *res, const v3f_t *a, const v3f_t *b, float t)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_nlerp(a, b, t);
+
+	return res;
+}
+
+
+/*
+ *       1 ab-------bb
+ *       | |         |
+ *       | |         |
+ *       | |         |
+ *       0 aa-------ba
+ *  t_x:   0---------1
+ *       ^
+ *       t_y
+ */
+static inline v3f_t _v3f_bilerp(const v3f_t *aa, const v3f_t *ab, const v3f_t *ba, const v3f_t *bb, float t_x, float t_y)
+{
+	v3f_t	xa = _v3f_lerp(aa, ba, t_x);
+	v3f_t	xb = _v3f_lerp(ab, bb, t_x);
+
+	return _v3f_lerp(&xa, &xb, t_y);
+}
+
+
+static inline v3f_t * v3f_bilerp(v3f_t *res, const v3f_t *aa, const v3f_t *ab, const v3f_t *ba, const v3f_t *bb, float t_x, float t_y)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_bilerp(aa, ab, ba, bb, t_x, t_y);
+
+	return res;
+}
+
+
+/*
+ *     abb-------bbb
+ *     /|        /|
+ *   aba-------bba|
+ *    | |       | |
+ *    |aab------|bab
+ *    |/        |/
+ *   aaa-------baa
+ */
+static inline v3f_t _v3f_trilerp(const v3f_t *aaa, const v3f_t *aba, const v3f_t *aab, const v3f_t *abb, const v3f_t *baa, const v3f_t *bba, const v3f_t *bab, const v3f_t *bbb, float t_x, float t_y, float t_z)
+{
+	v3f_t	xya = _v3f_bilerp(aaa, aba, baa, bba, t_x, t_y);
+	v3f_t	xyb = _v3f_bilerp(aab, abb, bab, bbb, t_x, t_y);
+
+	return _v3f_lerp(&xya, &xyb, t_z);
+}
+
+
+static inline v3f_t * v3f_trilerp(v3f_t *res, const v3f_t *aaa, const v3f_t *aba, const v3f_t *aab, const v3f_t *abb, const v3f_t *baa, const v3f_t *bba, const v3f_t *bab, const v3f_t *bbb, float t_x, float t_y, float t_z)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_trilerp(aaa, aba, aab, abb, baa, bba, bab, bbb, t_x, t_y, t_z);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_cross(const v3f_t *a, const v3f_t *b)
+{
+	return (v3f_t){
+		.x = a->y * b->z - a->z * b->y,
+		.y = a->z * b->x - a->x * b->z,
+		.z = a->x * b->y - a->y * b->x,
+	};
+}
+
+
+static inline v3f_t * v3f_cross(v3f_t *res, const v3f_t *a, const v3f_t *b)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_cross(a, b);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_rand(const v3f_t *min, const v3f_t *max)
+{
+	return (v3f_t){
+		.x = min->x + (float)rand() * (1.f/RAND_MAX) * (max->x - min->x),
+		.y = min->y + (float)rand() * (1.f/RAND_MAX) * (max->y - min->y),
+		.z = min->z + (float)rand() * (1.f/RAND_MAX) * (max->z - min->z),
+	};
+}
+
+
+static inline v3f_t * v3f_rand(v3f_t *res, const v3f_t *min, const v3f_t *max)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_rand(min, max);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_ceil(const v3f_t *v)
+{
+	return (v3f_t){
+		.x = ceilf(v->x),
+		.y = ceilf(v->y),
+		.z = ceilf(v->z),
+	};
+}
+
+
+static inline v3f_t * v3f_ceil(v3f_t *res, const v3f_t *v)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_ceil(v);
+
+	return res;
+}
+
+
+static inline v3f_t _v3f_floor(const v3f_t *v)
+{
+	return (v3f_t){
+		.x = floorf(v->x),
+		.y = floorf(v->y),
+		.z = floorf(v->z),
+	};
+}
+
+
+static inline v3f_t * v3f_floor(v3f_t *res, const v3f_t *v)
+{
+	if (_v3f_allocated(&res))
+		*res = _v3f_floor(v);
+
+	return res;
+}
+
+#endif