[vlc-devel] [PATCH v2 1/8] viewpoint: add reverse viewpoint function

[Alexandre Janniaux]

It reverses the transformation (here rotation only) which is helpful to
convert the viewpoint rotation into a world rotation for video outputs.
---
 include/vlc_viewpoint.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/vlc_viewpoint.h b/include/vlc_viewpoint.h
index b9e162b02e..7c11c86323 100644
--- a/include/vlc_viewpoint.h
+++ b/include/vlc_viewpoint.h
@@ -59,4 +59,18 @@ static inline void vlc_viewpoint_clip( vlc_viewpoint_t *p_vp )
                           FIELD_OF_VIEW_DEGREES_MAX );
 }
 
+/**
+ * Reverse the viewpoint rotation.
+ *
+ * It can be used to convert a camera view into a world transformation.
+ *
+ * \param vp the viewpoint for which the rotation need to be reversed
+ */
+static inline void vlc_viewpoint_reverse( vlc_viewpoint_t *vp )
+{
+    vp->yaw   *= -1;
+    vp->pitch *= -1;
+    vp->roll  *= -1;
+}
+
 #endif /* VLC_VIEWPOINT_H_ */
-- 
2.21.0