2 files changed, 21 insertions, 14 deletions

diff --git a/core/os/os.cpp b/core/os/os.cpp
index 8088a6fa74..7010d44930 100644
--- a/core/os/os.cpp
+++ b/core/os/os.cpp
@@ -536,12 +536,21 @@ String OS::get_joy_guid(int p_device) const {
 
 void OS::set_context(int p_context) {
 }
+
+OS::SwitchVSyncCallbackInThread OS::switch_vsync_function = NULL;
+
 void OS::set_use_vsync(bool p_enable) {
+	_use_vsync = p_enable;
+	if (switch_vsync_function) { //if a function was set, use function
+		switch_vsync_function(p_enable);
+	} else { //otherwise just call here
+		_set_use_vsync(p_enable);
+	}
 }
 
 bool OS::is_vsync_enabled() const {
 
-	return true;
+	return _use_vsync;
 }
 
 OS::PowerState OS::get_power_state() {
@@ -606,10 +615,6 @@ bool OS::has_feature(const String &p_feature) {
 	return false;
 }
 
-void *OS::get_stack_bottom() const {
-	return _stack_bottom;
-}
-
 OS::OS() {
 	void *volatile stack_bottom;
 
diff --git a/core/os/os.h b/core/os/os.h
index 41500acd93..2faaa6ab8f 100644
--- a/core/os/os.h
+++ b/core/os/os.h
@@ -58,6 +58,7 @@ class OS {
 	int _exit_code;
 	int _orientation;
 	bool _allow_hidpi;
+	bool _use_vsync;
 
 	char *last_error;
 
@@ -435,8 +436,16 @@ public:
 
 	virtual void set_context(int p_context);
 
-	virtual void set_use_vsync(bool p_enable);
-	virtual bool is_vsync_enabled() const;
+	//amazing hack because OpenGL needs this to be set on a separate thread..
+	//also core can't access servers, so a callback must be used
+	typedef void (*SwitchVSyncCallbackInThread)(bool);
+
+	static SwitchVSyncCallbackInThread switch_vsync_function;
+	void set_use_vsync(bool p_enable);
+	bool is_vsync_enabled() const;
+
+	//real, actual overridable function to switch vsync, which needs to be called from graphics thread if needed
+	virtual void _set_use_vsync(bool p_enable) {}
 
 	virtual OS::PowerState get_power_state();
 	virtual int get_power_seconds_left();
@@ -445,13 +454,6 @@ public:
 	virtual void force_process_input(){};
 	bool has_feature(const String &p_feature);
 
-	/**
-	 * Returns the stack bottom of the main thread of the application.
-	 * This may be of use when integrating languages with garbage collectors that
-	 * need to check whether a pointer is on the stack.
-	 */
-	virtual void *get_stack_bottom() const;
-
 	bool is_hidpi_allowed() const { return _allow_hidpi; }
 	OS();
 	virtual ~OS();