// generate an array with 1's and 0's

tileSize = 8

w = room_width
h = room_height

colMap[w/tileSize , h/tileSize ] = 0

for( xx=0 ; xx < w ; xx += tileSize ) {
    for( yy=0 ; yy < h ; yy += tileSize) {
        if tile_layer_find( 100 , xx , yy ) {
            colMap[ xx/tileSize , yy/tileSize ] = 1
            else colMap[ xx/tileSize , yy/tileSize ] = 0
//            show_debug_message("tilefind!")
            }

        }
    }