*: 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, 87 insertions, 0 deletions

diff --git a/src/v4f.h b/src/v4f.h
new file mode 100644
index 0000000..1356afb
--- /dev/null
+++ b/src/v4f.h
@@ -0,0 +1,87 @@
+/*
+ *  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 _V4F_H
+#define _V4F_H
+
+#include <math.h>
+
+typedef struct v4f_t {
+	float	x, y, z, w;
+} v4f_t;
+
+
+static inline v4f_t v4f_add(const v4f_t *a, const v4f_t *b)
+{
+	return (v4f_t){a->x + b->x, a->y + b->y, a->z + b->z, a->w + b->w};
+}
+
+
+static inline v4f_t v4f_sub(const v4f_t *a, const v4f_t *b)
+{
+	return (v4f_t){a->x - b->x, a->y - b->y, a->z - b->z, a->w - b->w};
+}
+
+
+static inline v4f_t v4f_mult(const v4f_t *a, const v4f_t *b)
+{
+	return (v4f_t){a->x * b->x, a->y * b->y, a->z * b->z, a->w * b->w};
+}
+
+
+static inline v4f_t v4f_mult_scalar(const v4f_t *v, float scalar)
+{
+	return (v4f_t){v->x * scalar, v->y * scalar, v->z * scalar, v->w * scalar};
+}
+
+
+static inline float v4f_dot(v4f_t *a, v4f_t *b)
+{
+	return a->x * b->x + a->y * b->y + a->z * b->z + a->w * b->w;
+}
+
+
+static inline float v4f_length(v4f_t *v)
+{
+	return sqrtf(v4f_dot(v, v));
+}
+
+
+static inline v4f_t v4f_normalize(v4f_t *v)
+{
+	return v4f_mult_scalar(v, 1.0f / v4f_length(v));
+}
+
+
+static inline v4f_t v4f_lerp(const v4f_t *a, const v4f_t *b, float t)
+{
+	v4f_t	lerp_a, lerp_b;
+
+	lerp_a = v4f_mult_scalar(a, 1.0f - t);
+	lerp_b = v4f_mult_scalar(b, t);
+
+	return v4f_add(&lerp_a, &lerp_b);
+}
+
+
+static inline v4f_t v4f_nlerp(const v4f_t *a, const v4f_t *b, float t)
+{
+	v4f_t	lerp = v4f_lerp(a, b, t);
+
+	return v4f_normalize(&lerp);
+}
+
+#endif