shader_environment

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Environment shaders are intended for opaque and alpha-tested surfaces in BSPs. A key feature of this shader is its ability to blend between two detail maps, making it ideal for outdoor ground shaders. It also supports cubemaps, normal maps, and masked specularity which can be used for metallic surfaces like Forerunner structures.

When the "is alpha tested" flag is checked, the normal map's alpha channel can be used to mask the material. In this case, the material is either fully opaque or fully transparent depending on the alpha value. The billboard trees outside Timberland make use of this feature.

Use by gbxmodels

When a gbxmodel references this shader type it will not render correctly in Custom Edition due to renderer bugs. Some affected scenery include the teleporter base and human barricades.

It is not recommended to use this shader type for custom objects when targeting Custom Edition.

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_environment tag.

Field Type Comments

shader environment flags bitfield(16)

Flag	Mask	Comments
alpha tested	`0x1`
bump map is specular mask	`0x2`
true atmospheric fog	`0x4`

shader environment type enum

Option	Value	Comments
normal	`0x0`
blended	`0x1`
blended base specular	`0x2`

lens flare spacing f32

lens flare

Reference^?: lens_flare

pad(44)

diffuse flags bitfield(16)

Flag	Mask	Comments
rescale detail maps	`0x1`
rescale bump map	`0x2`

pad(2)

pad(24)

base map

Reference^?: bitmap

pad(24)

detail map function enum

Option	Value	Comments
double biased multiply	`0x0`
multiply	`0x1`
double biased add	`0x2`

pad(2)

primary detail map scale f32

primary detail map

Reference^?: bitmap

secondary detail map scale f32

secondary detail map

Reference^?: bitmap

pad(24)

micro detail map function enum

Option	Value	Comments
double biased multiply	`0x0`
multiply	`0x1`
double biased add	`0x2`

pad(2)

micro detail map scale f32

micro detail map

Reference^?: bitmap

material color

ColorRGB (3)

red: f32
green: f32
blue: f32

pad(12)

bump map scale

f32

Default value: 1

bump map

Reference^?: bitmap

bump map scale xy

Point2D (little endian^?) (2)

x: f32
y: f32

Only set when the tag is compiled into a map cache.

pad(16)

u animation function enum

Option	Value	Comments
one	`0x0`
zero	`0x1`
cosine	`0x2`
cosine variable period	`0x3`
diagonal wave	`0x4`
diagonal wave variable period	`0x5`
slide	`0x6`
slide variable period	`0x7`
noise	`0x8`
jitter	`0x9`
wander	`0xa`
spark	`0xb`

pad(2)

u animation period

f32 (seconds)

Default value: 1

u animation scale

f32 (base map repeats)

Default value: 1

v animation function enum

Option	Value	Comments
one	`0x0`
zero	`0x1`
cosine	`0x2`
cosine variable period	`0x3`
diagonal wave	`0x4`
diagonal wave variable period	`0x5`
slide	`0x6`
slide variable period	`0x7`
noise	`0x8`
jitter	`0x9`
wander	`0xa`
spark	`0xb`

pad(2)

v animation period

f32 (seconds)

Default value: 1

v animation scale

f32 (base map repeats)

Default value: 1

pad(24)

self illumination flags bitfield(16)

Flag	Mask	Comments
unfiltered	`0x1`

pad(2)

pad(24)

primary on color

ColorRGB (3)

red: f32
green: f32
blue: f32

primary off color

ColorRGB (3)

red: f32
green: f32
blue: f32

primary animation function enum

Option	Value	Comments
one	`0x0`
zero	`0x1`
cosine	`0x2`
cosine variable period	`0x3`
diagonal wave	`0x4`
diagonal wave variable period	`0x5`
slide	`0x6`
slide variable period	`0x7`
noise	`0x8`
jitter	`0x9`
wander	`0xa`
spark	`0xb`

pad(2)

primary animation period

f32 (seconds)

Default value: 1

primary animation phase f32 (seconds)

pad(24)

secondary on color

ColorRGB (3)

red: f32
green: f32
blue: f32

secondary off color

ColorRGB (3)

red: f32
green: f32
blue: f32

secondary animation function enum

Option	Value	Comments
one	`0x0`
zero	`0x1`
cosine	`0x2`
cosine variable period	`0x3`
diagonal wave	`0x4`
diagonal wave variable period	`0x5`
slide	`0x6`
slide variable period	`0x7`
noise	`0x8`
jitter	`0x9`
wander	`0xa`
spark	`0xb`

pad(2)

secondary animation period

f32 (seconds)

Default value: 1

secondary animation phase f32 (seconds)

pad(24)

plasma on color

ColorRGB (3)

red: f32
green: f32
blue: f32

plasma off color

ColorRGB (3)

red: f32
green: f32
blue: f32

plasma animation function enum

Option	Value	Comments
one	`0x0`
zero	`0x1`
cosine	`0x2`
cosine variable period	`0x3`
diagonal wave	`0x4`
diagonal wave variable period	`0x5`
slide	`0x6`
slide variable period	`0x7`
noise	`0x8`
jitter	`0x9`
wander	`0xa`
spark	`0xb`

pad(2)

plasma animation period

f32 (seconds)

Default value: 1

plasma animation phase f32 (seconds)

pad(24)

map scale

f32

Default value: 1

map

Reference^?: bitmap

pad(24)

specular flags bitfield(16)

Flag	Mask	Comments
overbright	`0x1`
extra shiny	`0x2`
lightmap is specular	`0x4`

pad(2)

pad(16)

brightness

Fraction: f32

Maximum: 1

pad(20)

perpendicular color

ColorRGB (3)

red: f32
green: f32
blue: f32

parallel color

ColorRGB (3)

red: f32
green: f32
blue: f32

pad(16)

reflection flags bitfield(16)

Flag	Mask	Comments
dynamic mirror	`0x1`

reflection type enum

Option	Value	Comments
bumped cube map	`0x0`
flat cube map	`0x1`
bumped radiosity	`0x2`

lightmap brightness scale

Fraction: f32

Maximum: 1

pad(28)

perpendicular brightness

Fraction: f32

Maximum: 1

parallel brightness

Fraction: f32

Maximum: 1

pad(16)

pad(8)

pad(16)

reflection cube map

Reference^?: bitmap

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)