HDOS

This page is about an approved third-party Old School RuneScape client.

Using this specific third-party client is not a bannable offence. However, using third-party clients that are not on Jagex's approved list is a bannable offence. Always use third-party clients at your own risk. The wiki does not endorse any particular third-party client.

HDOS, or High-Detail Old School, is a closed-source third-party client for Old School RuneScape. It is one of two non-Jagex clients on the approved client list that players are permitted to use, along with RuneLite. When installed HDOS can be launched as a standalone client or through the official Jagex Launcher.

The stated goal of HDOS is to emulate the era of RuneScape HD that was originally released 1 July 2008.

History

Development of HDOS had officially begun by 8 May 2020.

On 17 June 2022, Jagex made an announcement regarding third-party clients, stating that only clients listed in the approved client list shall be allowable for players' use. HDOS received Jagex's approval alongside RuneLite and, at the time, OSBuddy.

HDOS was built on a 530 revision client. The engine is primarily written in Java, although Kotlin is also used for a variety of applications.

Features

HDOS is an entirely standalone client, as opposed to other third-party clients that work via "client injection" — modifying the binary code of the official Jagex client. Modifications to the game engine can be performed because the HDOS client is written independently from the official Old School RuneScape client, allowing for unique capabilities and features.

Increased performance

HDOS is capable of utilising multiple CPU cores at a time and introduces a rendering pipeline that uses more up to date technology than the original game engine, resulting in much higher 3D rendering performance. As a result, HDOS maintains stable framerates on a larger range of hardware.

Plugins

Similarly to RuneLite, HDOS features support for plugins which extend the functionality of the client. The first client revision to feature plugin support was released on 28 April 2022. Although the first batch included a set amount of user-voted plugins, as of early 2023 the plugins are handled in a subsystem within the client, which supports direct forking of RuneLite plugins as well as further modifications for HDOS's engine.

Increased view distance

Unrestored Lumbridge (view distance: 6)

Restored Lumbridge (view distance: 12)

In Old School RuneScape, the player is normally able to see up to 111 tiles away. In the HDOS client, the player is now able to render up to 200 tiles.

Rendering NPCs in distance

Using the official client, NPCs are only rendered up to a certain view distance, as it was never intended for the player to see further than 111 tiles.

HDOS includes an option to render NPCs further away, to account for the increased view distance of the client. To accomplish this effect, the client will load the data of the region the player is in, as well as the regions they are able to view depending on their set view distance. For NPCs that extend past the normal range of 56 tiles, the HDOS client will detect where those NPCs would be and instead spawn "fake NPCs". Because this effect is client-sided, NPCs past the normal range are not able to be interacted with.

Map restoration

Shortly after the RuneScape High Detail update in 2008, Jagex made an effort to overhaul and modernise many areas in RuneScape utilising the new features RuneTek 4 had to offer. A significant part of the HDOS project is to restore areas of the Old School RuneScape map to reflect the look and feel they had during their post-HD update era. This is done by making modifications to maps in compliance with Old School RuneScape's server-side rules. To achieve this, the HDOS client also leverages the ability to remove or add entities that are not actually present in the Old School RuneScape.

Map region filtering

Fire Altar (Map Region Filtering off)

Fire Altar (Map Region Filtering on)

Old School RuneScape maps are loaded in "regions" — 64x64 tile areas comprised of several 8x8 "chunks" — which are organized on a grid that Jagex uses to produce the world map.

Underground areas and certain other instances are kept separate from the mainland map of the game. Because of this, extending the view distance resulted in revealing areas that were never intended to be seen from certain positions. Map Region Filtering is able to correct this and filter out areas that were not intended for player view.

External links

• HDOS website
• HDOS GitLab repository