From 644ab878cf20224d7e5f675089f009e796a9a8fe Mon Sep 17 00:00:00 2001
From: Vito Caputo <vcaputo@pengaru.com>
Date: Mon, 6 May 2019 22:20:50 -0700
Subject: v2f: add bi-linear interpolation: v2f_bilerp()

---
 v2f.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

(limited to 'v2f.h')

diff --git a/v2f.h b/v2f.h
index 4cbabd4..382b5b0 100644
--- a/v2f.h
+++ b/v2f.h
@@ -222,4 +222,32 @@ static inline v2f_t * v2f_nlerp(v2f_t *res, const v2f_t *a, const v2f_t *b, floa
 	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;
+}
+
 #endif
-- 
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