Adding template project

vendor/rmlui_backend/RmlUi_Backend.h

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <RmlUi/Core/Input.h>
+#include <RmlUi/Core/RenderInterface.h>
+#include <RmlUi/Core/SystemInterface.h>
+#include <RmlUi/Core/Types.h>
+
+using KeyDownCallback = bool (*)(Rml::Context* context, Rml::Input::KeyIdentifier key, int key_modifier, float native_dp_ratio, bool priority);
+
+/**
+    This interface serves as a basic abstraction over the various backends included with RmlUi. It is mainly intended as an example to get something
+    simple up and running, and provides just enough functionality for the included samples.
+
+    This interface may be used directly for simple applications and testing. However, for anything more advanced we recommend to use the backend as a
+    starting point and copy relevant parts into the main loop of your application. On the other hand, the underlying platform and renderer used by the
+    backend are intended to be re-usable as is.
+ */
+namespace Backend {
+
+// Initializes the backend, including the custom system and render interfaces, and opens a window for rendering the RmlUi context.
+bool Initialize(const char* window_name, int width, int height, bool allow_resize);
+// Closes the window and release all resources owned by the backend, including the system and render interfaces.
+void Shutdown();
+
+// Returns a pointer to the custom system interface which should be provided to RmlUi.
+Rml::SystemInterface* GetSystemInterface();
+// Returns a pointer to the custom render interface which should be provided to RmlUi.
+Rml::RenderInterface* GetRenderInterface();
+
+// Polls and processes events from the current platform, and applies any relevant events to the provided RmlUi context and the key down callback.
+// @return False to indicate that the application should be closed.
+bool ProcessEvents(Rml::Context* context, KeyDownCallback key_down_callback = nullptr, bool power_save = false);
+// Request application closure during the next event processing call.
+void RequestExit();
+
+// Prepares the render state to accept rendering commands from RmlUi, call before rendering the RmlUi context.
+void BeginFrame();
+// Presents the rendered frame to the screen, call after rendering the RmlUi context.
+void PresentFrame();
+
+} // namespace Backend