Water 101

[Sparky]

Here, let's discuss how to implement water by using traditional modding techniques. First, read the following excerpt from the Halo PC Editing Reference to learn how the game engine handles water:

Water and Water Volumes in Halo

Water in Halo is very simple, almost to the point where water does not truly exist (at least in the sense that most people that have edited or created water in other games are used to). This is understandable since there are no specifically designed underwater missions or environments in Halo. In the case of streams, the water is shallow and the player cannot get under the surfaces of the water and be completely immersed. Couple these facts with the game play mechanic that the player in the role of the Master Chief has a self contained suit of armor and has no fear of drowning, there was no need for complicated underwater player behaviors, physics, and effects.

The majority of water encountered is in the form of simple streams. This kind of "water" has 2 parts: a stream surface with a shader whose settings simulate a water surface (small waves, flowing water, etc...) and the terrain underneath which has specific settings so that when objects interact with the terrain water effects occur (particles, sprites, sounds, etc...) giving the appearance that the stream itself is water. It is this kind of water that is demonstrated in the tutorial below.

There is one instance in the game where a large volume of water exists that the player can interact with or go "completely under water", this occurs for the island level in single player Halo, Silent Cartographer and in its multiplayer derivative, Death Island.

In this instance, the water is still very simple. Just like the stream example, there are the water surfaces that have the water shader effects and the terrain or surfaces underneath that are setup to simulate water with the effects that occur when objects interact with these surfaces. In the case of the water surfaces, these are defined with a .shader_transparent_water where as the streams use .shader_transparent_chicago or shader_transparent_chicago_extended shader tags. The water is made to have no collision using the "!" Render Only Shader Symbol just as with the stream example below.

The combination of the .shader_transparent_water and water fog volumes described below determine additional game behaviors such as the ability of vehicles to travel over the water (Ghosts will eventually stop and sink).

For large volumes of water, a water fog volume is created. This is done by adding the fog plane Shader Symbol "$" to the material names for the water surfaces, or a similar plane is created with another fog plane defined shader assigned to the surfaces of the plane. The volume is defined to be a water fog volume by enabling the "is water" flag located in the .fog tag.

Fog planes or volumes (suchs as those seen throughout the game and in the chasm in the multiplayer level Gephyrophobia) as well as water fog volumes are all created in a similar manner.

Make a plane that covers the entire area and extends past the level borders (this plane does not have to follow the Sealed World Rules), face the normals for the faces of the plane upwards, apply a material with the fog plane symbol or use the +unused special material (this material has no collision nor will it draw) with the fog plane symbol (to create the material +unused$). In Sapien, create a fog reference (a .fog tag that contains fog color and density as well as other properties) for the "fog palette" and then enter the volume and set the .fog palette entry to be applied to this volume.

How can we bring this effectively to Halo Demo, without any HEK use at all? (I guess I'll say now that I'm about to create a water plane scenery tag that will look appropriate, but how would we do this without using Halo CE's HEK?)

[Modzy]

A few ways:

• Using invisible scen with water coll and another water-like shader'd scen above it.
• Creating a fog plane and using water shader'd scen above it.
• Create a fog plane and add a material to the BSP that is shader'd like water, above the plane.

None of these are impossible. The first two are very easy, the latter is still achievable without HEK.