From b21df8fc37ce40cb43c88615ef7471075b61a968 Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Mon, 9 Apr 2018 22:26:23 +0300
Subject: [PATCH] inverse of quaternion

---
 include/cglm/quat.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/cglm/quat.h b/include/cglm/quat.h
index f824010..a2556dd 100644
--- a/include/cglm/quat.h
+++ b/include/cglm/quat.h
@@ -196,6 +196,20 @@ glm_quat_conjugate(versor q, versor dest) {
   dest[3] = -dest[3];
 }
 
+/*!
+ * @brief inverse of non-zero quaternion
+ *
+ * @param[in]   q    quaternion
+ * @param[out]  dest inverse quaternion
+ */
+CGLM_INLINE
+void
+glm_quat_inv(versor q, versor dest) {
+  versor conj;
+  glm_quat_conjugate(q, conj);
+  glm_vec_scale(conj, glm_vec4_norm2(q), dest);
+}
+
 /*!
  * @brief convert quaternion to mat4
  *