*: initial implementation of pig

This is nothing to write home about, but it provides a little sandbox for
developing shader-generated textures in the spirit of shadertoy or the
demoscene tool bonzomatic.

It's more oriented towards developing shaders for use with libstage in
the small games I've been hacking on.

1 files changed, 105 insertions, 0 deletions

diff --git a/src/v3f.h b/src/v3f.h
new file mode 100644
index 0000000..29ae3f7
--- /dev/null
+++ b/src/v3f.h
@@ -0,0 +1,105 @@
+/*
+ *  Copyright (C) 2018-2020 - 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/>.
+ */
+
+#ifndef _V3F_H
+#define _V3F_H
+
+#include <math.h>
+
+typedef struct v3f_t {
+	float	x, y, z;
+} v3f_t;
+
+
+static inline int v3f_equal(const v3f_t *a, const v3f_t *b)
+{
+	return (a->x == b->x && a->y == b->y && a->z == b->z);
+}
+
+
+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_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_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_scalar(const v3f_t *v, float scalar)
+{
+	return (v3f_t){v->x * scalar, v->y * scalar, v->z * scalar};
+}
+
+
+static inline float v3f_dot(v3f_t *a, v3f_t *b)
+{
+	return a->x * b->x + a->y * b->y + a->z * b->z;
+}
+
+
+static inline float v3f_length(v3f_t *v)
+{
+	return sqrtf(v3f_dot(v, v));
+}
+
+
+static inline v3f_t v3f_normalize(v3f_t *v)
+{
+	return v3f_mult_scalar(v, 1.0f / v3f_length(v));
+}
+
+
+static inline v3f_t v3f_cross(const v3f_t *a, const v3f_t *b)
+{
+	v3f_t	v;
+
+	v.x = a->y * b->z - a->z * b->y;
+	v.y = a->z * b->x - a->x * b->z;
+	v.z = a->x * b->y - a->y * b->x;
+
+	return v;
+}
+
+
+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_nlerp(const v3f_t *a, const v3f_t *b, float t)
+{
+	v3f_t	lerp = v3f_lerp(a, b, t);
+
+	return v3f_normalize(&lerp);
+}
+
+#endif