[vlc-devel] WG: [PATCH] Added a Linux headtracker

Christian Hoene christian.hoene at symonics.com
Tue Feb 21 14:42:17 CET 2017


Hi,

I added a headtracker interface to VLC, which works with Linux.
It can be used for 3d audio or 360┬░ videos.

Any comments to this first patch?

With best regards,

 Christian Hoene


-----Urspr├╝ngliche Nachricht-----
Von: Christian Hoene [mailto:christian.hoene at symonics.com] 
Gesendet: Dienstag, 21. Februar 2017 14:40
An: christian.hoene at symonics.com
Betreff: [PATCH] Added a Linux headtracker

---
 bin/vlc.c                      |   3 +
 modules/control/Makefile.am    |   3 +
 modules/control/headtracking.c | 248
+++++++++++++++++++++++++++++++++++++++++
 3 files changed, 254 insertions(+)
 create mode 100644 modules/control/headtracking.c

diff --git a/bin/vlc.c b/bin/vlc.c
index 0a33a0f..6c7913f 100644
--- a/bin/vlc.c
+++ b/bin/vlc.c
@@ -235,6 +235,9 @@ int main( int i_argc, const char *ppsz_argv[] )
     libvlc_set_user_agent (vlc, "VLC media player", "VLC/"PACKAGE_VERSION);
 
     libvlc_add_intf (vlc, "hotkeys,none");
+#if !defined (_WIN32) && !defined (__OS2__) && !defined (__APPLE__)
+    libvlc_add_intf (vlc, "headtracking,none"); #endif
 #if !defined (__OS2__)
     libvlc_add_intf (vlc, "globalhotkeys,none");  #endif diff --git
a/modules/control/Makefile.am b/modules/control/Makefile.am index
2469a86..56ebf03 100644
--- a/modules/control/Makefile.am
+++ b/modules/control/Makefile.am
@@ -8,11 +8,14 @@ libnetsync_plugin_la_SOURCES = control/netsync.c
libnetsync_plugin_la_LIBADD = $(SOCKET_LIBS)  liboldrc_plugin_la_SOURCES =
control/oldrc.c control/intromsg.h  liboldrc_plugin_la_LIBADD =
$(SOCKET_LIBS) $(LIBM)
+libheadtracking_plugin_la_SOURCES = control/headtracking.c 
+libheadtracking_plugin_la_LIBADD = $(LIBM)
 
 control_LTLIBRARIES = \
 	libdummy_plugin.la \
 	libgestures_plugin.la \
 	libhotkeys_plugin.la \
+	libheadtracking_plugin.la \
 	libnetsync_plugin.la \
 	liboldrc_plugin.la
 
diff --git a/modules/control/headtracking.c b/modules/control/headtracking.c
new file mode 100644 index 0000000..49da670
--- /dev/null
+++ b/modules/control/headtracking.c
@@ -0,0 +1,248 @@
+/**********************************************************************
+*******
+ * headtracking.c: headtracking interface plugin
+ 
+***********************************************************************
+******
+ * Copyright (C) 2016 Christian Hoene, Symonics GmbH
+ * $Id$
+ *
+ * Authors: Christian Hoene <christian.hoene at symonics.com>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License version 2.1 as published by the Free Software Foundation.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation Inc. 59 Temple Place, Suite 330, Boston MA 02111-1307 
+USA  */
+
+/**********************************************************************
+*******
+ * Preamble
+ 
+***********************************************************************
+******/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#define VLC_MODULE_LICENSE VLC_LICENSE_GPL_2_PLUS #include 
+<vlc_common.h> #include <vlc_plugin.h> #include <vlc_interface.h> 
+#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> 
+#include <errno.h> #include <linux/joystick.h> #include <string.h>
+
+/**********************************************************************
+*******
+ * intf_sys_t: description and status of FB interface  
+***********************************************************************
+******/
+struct intf_sys_t
+{
+        libvlc_int_t* libvlc;
+
+	vlc_timer_t discoveryTimer;
+	vlc_thread_t queryThread;
+
+	int jsDevice;
+
+	int running;
+
+	double axes[3];
+};
+
+/**********************************************************************
+*******
+ * Local prototypes
+
****************************************************************************
*/
+static int  Open    ( vlc_object_t * );
+static void Close   ( vlc_object_t * );
+static int  ActionEvent( vlc_object_t *, char const *,
+                         vlc_value_t, vlc_value_t, void * );
+
+
+/**********************************************************************
+*******
+ * Module descriptor
+ 
+***********************************************************************
+******/
+
+vlc_module_begin ()
+    set_shortname( N_("Headtracking") )
+    set_description( N_("Headtracking interface") )
+    set_capability( "interface", 0 )
+    set_callbacks( Open, Close )
+    set_category( CAT_INTERFACE )
+    set_subcategory( SUBCAT_INTERFACE_CONTROL ) vlc_module_end ()
+
+static int jsDiscovery(intf_sys_t *p_sys) {
+	char filename[20];
+	int file,i;
+
+	for(i=0;i<32;i++) {
+		sprintf(filename,"/dev/input/js%d",i);
+		file = open(filename, O_RDONLY);
+		if(file >= 0)
+			break;
+	}
+	if(file == -1)
+		return 0;
+
+	p_sys->jsDevice = file;
+	msg_Info( p_sys->libvlc, "found joystick at %s", filename);
+
+	return 1;
+}
+
+static int jsQuery(intf_sys_t *p_sys)
+{
+	if(p_sys->jsDevice >= 0) {
+
+		/* at start up, all events are fired */
+		struct js_event event[10];
+		int n;
+		int fire=0;
+
+		/* blocking read, TODO: check for thread cancel */
+		n = read(p_sys->jsDevice, (void*)event, sizeof(event));
+		if(n < 0) {
+			msg_Info(p_sys->libvlc, "joystick error %d
%s",errno,strerror(errno));
+			close(p_sys->jsDevice);
+			p_sys->jsDevice = -1;
+			return -1;
+		}
+
+		for(struct js_event *e = event;n > 0; e++,n-=sizeof(*e)) {
+			if((e->type & ~JS_EVENT_INIT) == JS_EVENT_AXIS &&
e->number<3) {
+				p_sys->axes[e->number] = e->value * (180. /
32767.);
+				fire++;
+			}
+#ifdef DEBUG
+			else
+				msg_Info(p_sys->libvlc, "unknown js event
%9d %04X %02X %d %p\n", 
+e->time, e->value, e->type, e->number, p_sys->axes); #endif
+		}
+		if(fire) {
+			var_SetAddress(p_sys->libvlc, "head-rotation",
p_sys->axes);
+		}
+	}
+	return 1;
+}
+
+static void* query(void *p)
+{
+	intf_sys_t *p_sys = (intf_sys_t*)p;
+#ifdef DEBUG
+	msg_Info( p_sys->libvlc, "query thread started"); #endif
+
+	while(p_sys->running) {
+		vlc_testcancel();
+
+		if(jsQuery(p_sys)<0)
+			break;
+
+	}
+
+	p_sys->running = 0;
+
+	return NULL;
+}
+
+static void discovery(void *p)
+{
+	intf_sys_t *p_sys = (intf_sys_t*)p;
+
+	if(p_sys->running)
+		return;
+
+	if(!jsDiscovery(p_sys))
+		return;
+
+	p_sys->running = 1;
+	vlc_clone(&p_sys->queryThread, &query, p_sys, 
+VLC_THREAD_PRIORITY_INPUT); }
+
+
+/**********************************************************************
+*******
+ * Open: initialize headtracking interface  
+***********************************************************************
+******/ static int Open( vlc_object_t *p_this ) {
+    intf_thread_t *p_intf = (intf_thread_t *)p_this;
+    intf_sys_t *p_sys;
+    int res;
+
+    msg_Info( p_intf, "using the headtracking interface module..." );
+
+	/* get memory for structure */
+    p_sys = malloc( sizeof( intf_sys_t ) );
+    if( !p_sys )
+        return VLC_ENOMEM;
+    p_intf->p_sys = p_sys;
+
+    p_sys->libvlc = p_this->obj.libvlc;
+    p_sys->jsDevice = -1;
+    p_sys->running = 0;
+    p_sys->axes[0] = p_sys->axes[1] = p_sys->axes[2] = 0;
+
+	/* start HID discovery timer */
+    res = vlc_timer_create(&p_sys->discoveryTimer, &discovery, p_sys);
+    if(res != 0)
+	return VLC_EGENERIC;
+
+    vlc_timer_schedule(p_sys->discoveryTimer, false, 1000000, 5000000);
+
+	/* create notification object */
+    var_Create (p_sys->libvlc, "head-rotation", VLC_VAR_ADDRESS);
+    var_AddCallback(p_sys->libvlc, "head-rotation", ActionEvent, p_sys 
+);
+
+    msg_Info( p_intf, "done" );
+
+    return VLC_SUCCESS;
+}
+
+/**********************************************************************
+*******
+ * Close: destroy interface
+ 
+***********************************************************************
+******/ static void Close( vlc_object_t *p_this ) {
+    intf_thread_t *p_intf = (intf_thread_t *)p_this;
+    intf_sys_t *p_sys = p_intf->p_sys;
+
+    var_DelCallback( p_intf->obj.libvlc, "head-rotation", ActionEvent, 
+ p_intf );
+
+    /* destroy thread */
+    if(p_sys->running) {
+	vlc_cancel(p_sys->queryThread);
+	vlc_join(p_sys->queryThread, NULL);
+    }
+
+    /* destroy timer */
+    vlc_timer_destroy(p_sys->discoveryTimer);
+
+    /* Destroy structure */
+    free( p_sys );
+
+}
+
+/**********************************************************************
+*******
+ * ActionEvent: callback for hotkey actions  
+***********************************************************************
+******/
+
+static int ActionEvent( vlc_object_t *libvlc, char const *psz_var,
+                        vlc_value_t oldval, vlc_value_t newval, void 
+*pdata) {
+        VLC_UNUSED(oldval);
+        VLC_UNUSED(pdata);
+
+	double *axes = (double*) newval.p_address;
+	msg_Info(  libvlc, "%s yaw %4.0f pitch %4.0f roll %4.0f", psz_var,
axes[0], axes[1], axes[2]);
+	return VLC_SUCCESS;
+}
+
+
--
2.1.4





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