3 files changed, 75 insertions, 4 deletions

diff --git a/core/os/file_access.cpp b/core/os/file_access.cpp
index 7b2062936b..20c1221f2b 100644
--- a/core/os/file_access.cpp
+++ b/core/os/file_access.cpp
@@ -273,9 +273,62 @@ String FileAccess::get_token() const {
 	return String::utf8(token.get_data());
 }
 
+class CharBuffer {
+	Vector<char> vector;
+	char stack_buffer[256];
+
+	char *buffer;
+	int capacity;
+	int written;
+
+	bool grow() {
+
+		if (vector.resize(next_power_of_2(1 + written)) != OK) {
+
+			return false;
+		}
+
+		if (buffer == stack_buffer) { // first chunk?
+
+			for (int i = 0; i < written; i++) {
+
+				vector[i] = stack_buffer[i];
+			}
+		}
+
+		buffer = vector.ptrw();
+		capacity = vector.size();
+		ERR_FAIL_COND_V(written >= capacity, false);
+
+		return true;
+	}
+
+public:
+	_FORCE_INLINE_ CharBuffer() :
+			buffer(stack_buffer),
+			capacity(sizeof(stack_buffer) / sizeof(char)),
+			written(0) {
+	}
+
+	_FORCE_INLINE_ void push_back(char c) {
+
+		if (written >= capacity) {
+
+			ERR_FAIL_COND(!grow());
+		}
+
+		buffer[written++] = c;
+	}
+
+	_FORCE_INLINE_ const char *get_data() const {
+
+		return buffer;
+	}
+};
+
 String FileAccess::get_line() const {
 
-	CharString line;
+	CharBuffer line;
 
 	CharType c = get_8();
 
diff --git a/core/os/os.cpp b/core/os/os.cpp
index d81e70e612..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() {
diff --git a/core/os/os.h b/core/os/os.h
index d9f7b91daa..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();