v3f: add bi-linear interpolation: v3f_bilerp()

1 files changed, 28 insertions, 0 deletions

diff --git a/v3f.h b/v3f.h
index ad6e373..aca6e1f 100644
--- a/v3f.h
+++ b/v3f.h
@@ -209,6 +209,34 @@ static inline v3f_t * v3f_nlerp(v3f_t *res, const v3f_t *a, const v3f_t *b, floa
 }
 
 
+/*
+ *       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;
+}
+
+
 static inline v3f_t _v3f_cross(const v3f_t *a, const v3f_t *b)
 {
 	return (v3f_t){