Dino's Complete Guide to
Ultima 1: The First Age of Darkness
CASTLE.4 File Format
Table of Contents
Overview
CASTLE.4 image

CASTLE.4 stores the CGA version of the castle image shown in the intro sequence. It is a single image and does not include the animations of the flags moving with the wind; those are stored elsewhere.

This is a 320x200 image using the standard CGA palette.

Composition
CASTLE.4 image

CASTLE.4 is 16384 bytes in length. It uses 2 bits per pixel; however its structure is not entirely sequential. The first half of the file (8192 bytes) contains the odd scanlines (8000 bytes) followed by 192 bytes of padding. The second half of the file (8192 bytes) contains the even scanlines (8000 bytes) followed by 192 bytes of padding.