oboy/src/screen.ml

type pixel = {
  r : char;
  g : char;
  b : char;
  a : char;
}

type t = {
  width  : int;
  height : int;
  data   : pixel array;
}

type control = {
  lcd_display_enable    : bool;
  tile_map_select       : int;
  window_display_enable : bool;
  tile_data_select      : int;
  bg_tile_map_select    : int;
  sprite_size           : int;
  sprite_enable         : bool;
  bg_display            : bool;
}

let get_lcd_control mem =
  let b = Memory.get mem 0xFF40 |> int_of_char in

  let lcd_display_enable = Bit.is_set b 7 in
  let tile_map_select = if not (Bit.is_set b 6) then 0x9800 else 0x9c00 in
  let window_display_enable = Bit.is_set b 5 in
  let tile_data_select = if not (Bit.is_set b 4) then 0x8800 else 0x8000 in
  let bg_tile_map_select = if not (Bit.is_set b 3) then 0x9800 else 0x9c00 in
  let sprite_size = if not (Bit.is_set b 2) then 8 else 16 in
  let sprite_enable = Bit.is_set b 1 in
  let bg_display = Bit.is_set b 0 in

  {
    lcd_display_enable;
    tile_map_select;
    window_display_enable;
    tile_data_select;
    bg_tile_map_select;
    sprite_size;
    sprite_enable;
    bg_display;
  }

let init_screen w h =
  {
    width = w;
    height = h;
    data = Array.make_matrix h w { r = 255; g = 255; b = 255; a = 255 }
  }