shader_transparent_water

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Water shaders are characterized by their use of layered animated ripple maps, tint colours, and reflectance.

They need not exclusively be used for water -- the coolant pools of Keyes (d20) also use water shaders, and the Halo CE Refined project uses them for some glass to better emulate Xbox glass shaders. They are also not exclusively used within the BSP, with skies like Damnation's also using this shader type.

Water shaders are not typically used for waterfalls (shader_transparent_chicago_extended) nor rivers (shader_transparent_chicago), though there are exceptions (the water in Battle Creek).

Known issues #

Ripple maps are not rendered correctly on PC compared to Xbox. The highest level of detail mipmap is used for the most distant areas, but water closer to the camera uses the lowest detail mipmap. This is the opposite of how it should be, and results in distant water suffering from major aliasing.

Structure and fields #

This tag inherits fields from shader which are not shown here. See the parent's page for more information. The following information is unique to the shader_transparent_water tag.

Field Type Comments

water flags bitfield(16)

Flag	Mask	Comments
base map alpha modulates reflection	`0x1`
base map color modulates background	`0x2`
atmospheric fog	`0x4`
draw before fog	`0x8`

pad(2)

pad(32)

base map

Reference^?: bitmap

pad(16)

view perpendicular brightness

Fraction: f32

Maximum: 1

view perpendicular tint color

ColorRGB

red: f32
green: f32
blue: f32

view parallel brightness

Fraction: f32

Maximum: 1
Default value: 1.

view parallel tint color

ColorRGB

red: f32
green: f32
blue: f32

pad(16)

reflection map

Reference^?: bitmap

pad(16)

ripple animation angle Angle: f32

ripple animation velocity f32

ripple scale

f32

Default value: 1.

ripple maps

Reference^?: bitmap

ripple mipmap levels u16

pad(2)

ripple mipmap fade factor

Fraction: f32

Maximum: 1

ripple mipmap detail bias f32

pad(64)

ripples

Block^?

Maximum: 4

Field	Type	Comments
	`pad(2)`
	`pad(2)`
contribution factor	`Fraction: f32`	Maximum: 1
	`pad(32)`
animation angle	`Angle: f32`
animation velocity	`f32`
map offset	`Vector2D` i: `f32` j: `f32`
map repeats	`u16`	Default value: 1.
map index	`Index: u16`
	`pad(16)`

pad(16)

This information was partially generated using Invader tag definitions.

Acknowledgements

Thanks to the following individuals for their research or contributions to this topic:

Kavawuvi (Invader tag definitions)
MosesOfEgypt (Tag structure research)