This command is used to draw a 2D box with rounded corners. The radius of the corners is determined by the radius parameter. It cannot be smaller than 1 or greater than the width/height of the box itself. The command will alter these values if they do not meet the criteria.
An optional colour value can be provided to override the colour set by D3D_COLOR.
D3D_ROUNDED_BOX Left, Top, Right, Bottom, Corner Radius
D3D_ROUNDED_BOX Left, Top, Right, Bottom, Corner Radius, Colour