Based on the code context, you can draw a rectangle using DrawTexturePro(), which is the most flexible option. The basic syntax is:
DrawTexturePro(texture, source, dest, origin, rotation, tint);Where dest is the Rectangle structure defining where and how large to draw the rectangle on screen. If you just need a solid colored rectangle without a texture, you can use the simpler DrawRectangle() function (though not shown in the provided context).