reduce FPS when out of focus

CPU usage is significant with a few instances running

src/editor/Renderer.cpp

@@ -67,6 +67,22 @@ void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
 	g_scroll += round(yoffset);
 }
 
+void window_focus_callback(GLFWwindow* window, int focused)
+{
+	g_app->isFocused = focused;
+}
+
+void cursor_enter_callback(GLFWwindow* window, int entered)
+{
+	g_app->isHovered = entered;
+}
+
+void window_iconify_callback(GLFWwindow* window, int iconified)
+{
+	g_app->isIconified = iconified;
+}
+
+
 Renderer::Renderer() {
 	g_settings.loadDefault();
 	g_settings.load();
@@ -108,6 +124,9 @@ Renderer::Renderer() {
 	glfwSetWindowPosCallback(window, window_pos_callback);
 	glfwSetWindowCloseCallback(window, window_close_callback);
 	glfwSetWindowMaximizeCallback(window, window_maximize_callback);
+	glfwSetWindowFocusCallback(window, window_focus_callback);
+	glfwSetCursorEnterCallback(window, cursor_enter_callback);
+	glfwSetWindowIconifyCallback(window, window_iconify_callback);
 
 	glewInit();
 
@@ -488,6 +507,10 @@ void Renderer::renderLoop() {
 		if (glerror != GL_NO_ERROR) {
 			logf("Got OpenGL Error: %d\n", glerror);
 		}
+
+		if (!isFocused && !isHovered) {
+			sleepms(50);
+		}
 	}
 
 	glfwTerminate();

src/editor/Renderer.h

@@ -78,6 +78,9 @@ class Renderer {
 	MergeResult mergeResult;
 
 	bool hideGui = false;
+	bool isFocused = false;
+	bool isHovered = false;
+	bool isIconified = false;
 
 	Renderer();
 	~Renderer();

src/util/util.cpp

@@ -916,3 +916,13 @@ string getConfigDir()
 	return string("") + getenv("HOME") + "/.config/bspguy/";
 }
 #endif
+
+
+void sleepms(uint32_t ms)
+{
+#ifdef _WIN32
+	Sleep(ms);
+#else
+	usleep(ms * 1000);
+#endif
+}

src/util/util.h

@@ -111,4 +111,6 @@ enum class FIXUPPATH_SLASH
 };
 
 void fixupPath(std::string& path, FIXUPPATH_SLASH needstartslash, FIXUPPATH_SLASH needendslash);
-void replaceAll(std::string& str, const std::string& from, const std::string& to);
+void replaceAll(std::string& str, const std::string& from, const std::string& to);
+
+void sleepms(uint32_t ms);