let rotate src dst alpha =

 let (w,h,_) = Sdlvideo.surface_dims pic

  let halfWidth = w / 2 in

   let halfHeight = h / 2 in

    let cosv = int_to_float(cos( -(alpha) / ((180 / 3.14159265)))) in

     let sinv = int_to_float(sin( -(alpha) / ((180 / 3.14159265)))) in

      let x = ref 1 in

           let y = ref 1 in

            while !x < w do

                (while !y < h do

                 let xOr = ((x-halfWidth) * int_to_float(Maths.cos alpha) + ((y - halfHeight) * sinv + halfWidth)) in

                  let yOr = int_to_float((x-halfWidth) * (Maths.cos alpha) + ((y - halfHeight) * sinv + halfWidth)) in

               if (xOr >= 0 && yOr >= 0 && xOr < dst.Width && yOr < dst.Height)

            Sdlvideo.put_pixel_color dst !x !y (Sqlvideo.get_pixel_color src xOr yOr)

                   y := !y+1

                  done;

                  x := !x+1;)

                done;

   dst