OCaml > Rotate Ocaml

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