From http://www.jwz.org/xscreensaver/xscreensaver-5.18.tar.gz

[xscreensaver] / hacks / glx / gltrackball.c

diff --git a/hacks/glx/gltrackball.c b/hacks/glx/gltrackball.c
index e3c0cd42402fdb781b03a48a0be8e502d4c7f9c9..93d4c54263ef97e2610616d794013e10f0acbc5d 100644 (file)
--- a/hacks/glx/gltrackball.c
+++ b/hacks/glx/gltrackball.c
@@ -1,4 +1,4 @@
-/* gltrackball, Copyright (c) 2002-2008 Jamie Zawinski <jwz@jwz.org>
+/* gltrackball, Copyright (c) 2002-2012 Jamie Zawinski <jwz@jwz.org>
  * GL-flavored wrapper for trackball.c
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
@@ -12,20 +12,25 @@
 
 #include <math.h>
 #include <stdlib.h>
+#include <string.h>
 
 #ifdef HAVE_CONFIG_H
 # include "config.h"
 #endif
 
-#ifdef HAVE_COCOA
-# include <OpenGL/gl.h>
-#else
+#ifndef HAVE_COCOA
 # include <GL/gl.h>
 #endif
 
+#ifdef HAVE_JWZGLES
+# include "jwzgles.h"
+#endif /* HAVE_JWZGLES */
+
 #include "trackball.h"
 #include "gltrackball.h"
 
+extern double current_device_rotation (void);  /* Bah, it's in fps.h */
+
 struct trackball_state {
   int x, y;
   GLfloat q[4];
@@ -43,6 +48,16 @@ gltrackball_init (void)
   return ts;
 }
 
+/* Reset the trackball to the default unrotated state.
+ */
+void
+gltrackball_reset (trackball_state *ts)
+{
+  memset (ts, 0, sizeof(*ts));
+  trackball (ts->q, 0, 0, 0, 0);
+}
+
+
 /* Begin tracking the mouse: Call this when the mouse button goes down.
    x and y are the mouse position relative to the window.
    w and h are the size of the window.