shader_transparent_chicago

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The transparent chicago shader is applied to surfaces that require transparent elements. This shader can contain up to 4 "stages" of bitmaps, where each stage and its alpha can animate and blend to form final accumulated diffuse and alpha channels. The shader can be given a final framebuffer blending function too, like add for holograms.

Alpha-tested BSP surfaces like 2D billboard trees and ladders can use the simpler shader_environment instead.

If referenced as an extra shader layer, this tag will inherit some fields from its parent regardless of its own flags (e.g. first map type).

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_chicago tag.

Field Type Comments

numeric counter limit u8

shader transparent chicago flags bitfield(8)

Flag	Mask	Comments
alpha tested	`0x1`
decal	`0x2`
two sided	`0x4`
first map is in screenspace	`0x8`
draw before water	`0x10`
ignore effect	`0x20`
scale first map with distance	`0x40`
numeric	`0x80`

first map type enum

Option	Value	Comments
2d map	`0x0`
first map is reflection cube map	`0x1`
first map is object centered cube map	`0x2`
first map is viewer centered cube map	`0x3`

framebuffer blend function enum

Option	Value	Comments
alpha blend	`0x0`
multiply	`0x1`
double multiply	`0x2`
add	`0x3`
subtract	`0x4`
component min	`0x5`
component max	`0x6`
alpha multiply add	`0x7`

framebuffer fade mode enum

Option	Value	Comments
none	`0x0`
fade when perpendicular	`0x1`
fade when parallel	`0x2`

framebuffer fade source enum

Option	Value	Comments
none	`0x0`
a out	`0x1`
b out	`0x2`
c out	`0x3`
d out	`0x4`

pad(2)

lens flare spacing f32

lens flare

Reference^?: lens_flare

extra layers

Block^?

Specifies additional shaders to render before this parent shader. The same geometry is essentially rendered multiple times with different shaders. Each extra layer shader can have an independent framebuffer blend function, but some settings like first map is reflection cube map from the parent will also override the setting in extra layers.

Although any shader type can be referenced here, only the chicago transparent shaders are properly supported; the other types will either not render or render incorrectly.

Warning: Using a shader with extra layers on an object with transparent self occlusion enabled causes Sapien to crash.

Field	Type	Comments
shader	`Reference^?`: shader

maps

Block^?

Maximum: 4

Field Type Comments

flags bitfield(16)

Flag	Mask	Comments
unfiltered	`0x1`
alpha replicate	`0x2`
u clamped	`0x4`
v clamped	`0x8`

pad(2)

pad(40)

color function enum

Option	Value	Comments
current	`0x0`
next map	`0x1`
multiply	`0x2`
double multiply	`0x3`
add	`0x4`
add signed current	`0x5`
add signed next map	`0x6`
subtract current	`0x7`
subtract next map	`0x8`
blend current alpha	`0x9`
blend current alpha inverse	`0xa`
blend next map alpha	`0xb`
blend next map alpha inverse	`0xc`

alpha function enum

Option	Value	Comments
current	`0x0`
next map	`0x1`
multiply	`0x2`
double multiply	`0x3`
add	`0x4`
add signed current	`0x5`
add signed next map	`0x6`
subtract current	`0x7`
subtract next map	`0x8`
blend current alpha	`0x9`
blend current alpha inverse	`0xa`
blend next map alpha	`0xb`
blend next map alpha inverse	`0xc`

pad(36)

map u scale

f32

Default value: 1

map v scale

f32

Default value: 1

map u offset f32

map v offset f32

map rotation f32

mipmap bias

Fraction: f32

Maximum: 1

map

Reference^?: bitmap

pad(40)

u animation source enum

Option	Value	Comments
none	`0x0`
a out	`0x1`
b out	`0x2`
c out	`0x3`
d out	`0x4`

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`

u animation period

f32 (seconds)

Default value: 1

u animation phase f32

u animation scale

f32 (world units)

Default value: 1

v animation source enum

Option	Value	Comments
none	`0x0`
a out	`0x1`
b out	`0x2`
c out	`0x3`
d out	`0x4`

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`

v animation period

f32 (seconds)

Default value: 1

v animation phase f32

v animation scale

f32 (world units)

Default value: 1

rotation animation source enum

Option	Value	Comments
none	`0x0`
a out	`0x1`
b out	`0x2`
c out	`0x3`
d out	`0x4`

rotation 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`

rotation animation period

f32 (seconds)

Default value: 1

rotation animation phase f32

rotation animation scale

f32 (degrees)

Default value: 360

rotation animation center

Point2D (2)

x: f32
y: f32

extra flags bitfield(32)

Flag	Mask	Comments
don't fade active camouflage	`0x1`
numeric countdown timer	`0x2`

pad(8)

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)