feat: animated background

app/src/main/java/gui/AnimatedBackground.java

@@ -0,0 +1,28 @@
+package gui;
+
+import imgui.ImGui;
+import imgui.ImVec2;
+import imgui.flag.ImGuiWindowFlags;
+
+public class AnimatedBackground {
+
+	private float backgroundOffset = 0;
+
+	public AnimatedBackground() {
+
+	}
+
+	public void render() {
+		backgroundOffset += ImGui.getIO().getDeltaTime() / 10.0f * Options.BackgroundSpeed;
+		var displaySize = ImGui.getIO().getDisplaySize();
+		ImGui.setNextWindowPos(new ImVec2(0.0f, 0.0f));
+		ImGui.setNextWindowSize(displaySize);
+		ImGui.begin("Background", null, ImGuiWindowFlags.NoDecoration | ImGuiWindowFlags.NoMove
+				| ImGuiWindowFlags.NoSavedSettings | ImGuiWindowFlags.NoBackground
+				| ImGuiWindowFlags.NoBringToFrontOnFocus | ImGuiWindowFlags.NoInputs);
+		ImGui.image(Images.BACKGROUND, displaySize, new ImVec2(backgroundOffset, backgroundOffset),
+				new ImVec2(1.0f + backgroundOffset, 1.0f + backgroundOffset));
+		ImGui.end();
+	}
+
+}