default Rect calculateGL11Frame() {
        // Convert frame to screen space anchored at bottom-left instead of top-left
        Rect screenFrame = getRoot().getScreenFrame();
        Rect frame = convertParentRectToScreen(getFrame());
        Rect bottomLeftFrame = new Rect(
                new Point(frame.x(), screenFrame.height() - frame.y() - frame.height()),
                frame.size);

        // Convert from GUI screen space to GL11 screen space using the Minecraft Gui Scale value
        double glWScale = getRoot().getMinecraft().getWindow().getGuiScale();
        double glHScale = getRoot().getMinecraft().getWindow().getGuiScale();
        Rect gl11Rect = new Rect(new Point((int) Math.round(bottomLeftFrame.x() * glWScale), (int) Math.round(bottomLeftFrame.y() * glHScale)),
                new Size((int) Math.round(bottomLeftFrame.width() * glWScale), (int) Math.round(bottomLeftFrame.height() * glHScale)));

        return gl11Rect;
    }
Calculates the GL11 screen-space equivalent this node's frame.

@return Bottom-left anchored frame in GL11 window space
core/src/main/java/mrtjp/projectred/redui/RedUINode.java