*: 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, 91 insertions, 0 deletions

diff --git a/src/v2f.h b/src/v2f.h
new file mode 100644
index 0000000..c890c8d
--- /dev/null
+++ b/src/v2f.h
@@ -0,0 +1,91 @@
+/*
+ *  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/>.
+ */
+
+#ifndef _V2F_H
+#define _V2F_H
+
+#include <math.h>
+
+typedef struct v2f_t {
+	float	x, y;
+} v2f_t;
+
+
+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_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_mult_scalar(const v2f_t *v, float scalar)
+{
+	return (v2f_t){ v->x * scalar, v->y * scalar };
+}
+
+
+static inline v2f_t v2f_div_scalar(const v2f_t *v, float scalar)
+{
+	return v2f_mult_scalar(v, 1.f / scalar);
+}
+
+
+static inline float v2f_dot(v2f_t *a, v2f_t *b)
+{
+	return a->x * b->x + a->y * b->y;
+}
+
+
+static inline float v2f_length(v2f_t *v)
+{
+	return sqrtf(v2f_dot(v, v));
+}
+
+
+static inline v2f_t v2f_normalize(v2f_t *v)
+{
+	float	f;
+
+	f = 1.0f / v2f_length(v);
+
+	return (v2f_t){ .x = f * v->x, .y = f * v->y };
+}
+
+
+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_nlerp(const v2f_t *a, const v2f_t *b, float t)
+{
+	v2f_t	lerp = v2f_lerp(a, b, t);
+
+	return v2f_normalize(&lerp);
+}
+
+#endif