/// draw_map_surf(x, y)
// leaks all variables, repositions calling instance..?
x = (argument0 - 3) * 8;
y = (argument1 - 3) * 8;
mystr = string(global.map[argument0, argument1]);
if (mystr != "0") {
    wallU = string_char_at(mystr, 1);
    wallR = string_char_at(mystr, 2);
    wallD = string_char_at(mystr, 3);
    wallL = string_char_at(mystr, 4);
    color = string_char_at(mystr, 5);
    //This line seems to change the underlying map color when the 8-bit shader is active
    //It causes the 8-bit shader to miscolor map blocks; commented out
    //if (oControl.shader_on == true) color = "2";
    special = string_char_at(mystr, 6);
    corner = string_char_at(mystr, 7);
    draw_mapblock(x, y, wallU, wallR, wallD, wallL, color, special, global.dmap[argument0, argument1], corner);
}