/******************************************************************************
** Functions by Derrick Sobodash
** http://www.cinnamonpirate.com/
** Submitted to ROM Hacking.net on July 3, 2006
******************************************************************************/

/******************************************************************************
** bmp2bpp()
*******************************************************************************
** syntax: string bmp2bpp(string bitmap, int t_width, int t_height[,
**         int rows, int cols])
*******************************************************************************
** Transforms bitmap from linear bitmap data to tile-based bitplane data.
** Tiles will be sized as t_widthxt_height. If rows and cols aren't
** specified, both will default to 16. The result will need to be further
** processed if you need to split apart color data.
******************************************************************************/

function bmp2bpp($bitmap, $t_width, $t_height, $rows = 16, $cols = 16)
{

  if($t_width == null || $bitmap == null || $t_height == null)
    die("Error: bmp2bpp(): Requires at least three non-null arguments\n\n");

  $ptr      = 0;
  $bitplane = "";

  for($k = 0; $k < $rows; $k ++)
  {
      
    for($i = 0; $i < $t_height; $i ++)
    {

      for($z = 0; $z < $cols; $z ++)
      {

        $tile[$z][$i] = substr($bitmap, $ptr, $t_width);
        $ptr += $t_width;

      }

    }

    for($z = $cols - 1; $z > -1; $z --)
    {

      for($i = 0; $i < $t_height; $i ++)
        $bitplane .= strrev($tile[$z][$i]);

    }

    unset($tile);

  }

  return($bitplane);

}


/******************************************************************************
** bpp2bmp()
*******************************************************************************
** syntax: string bpp2bmp(string bitplane, int t_width, int t_height[,
**         int rows, int cols])
*******************************************************************************
** Transforms bitplane from tile-based bitplane data to linear bitmap data.
** Tiles will be sized as t_widthxt_height. If rows and cols aren't
** specified, both will default to 16. The resulting pixel stream will need
** to be further processed into a valid graphic format.
******************************************************************************/

function bpp2bmp($bitplane, $t_width, $t_height, $rows = 16, $cols = 16)
{

  if($t_width == null || $bitplane == null || $t_height == null)
    die("Error: bpp2bmp(): Requires at least three non-null arguments\n\n");

  $bitmap  = "";
  $ptr     = 0;

  for($k = 0; $k < $rows; $k ++)
  {
      
    for($i = 0; $i < $cols; $i ++)
    {

      for($z = 0; $z < $t_height; $z ++)
      {

        $line[$i][$z] = substr($bitplane, $ptr, $t_width);
        $ptr = $ptr + $t_width;

      }

    }

    for($z = 0; $z < $t_height; $z ++)
    {

      for($i = $cols - 1; $i > -1; $i --)
        $bitmap .= strrev($line[$i][$z]);

    }

  }

  return($bitmap);

}