shader_transparent_chicago_extended

Transparent chicago extended shaders are essentially identical to shader_transparent_chicago, but have an additional 2-stage block used when video hardware does not support more than 2 maps in a shader (which can be simulated with arguments). There is no reason to use this shader type over shader_transparent_chicago on modern systems.

See shader_transparent_chicago for more documentation.

Structure and fields

Field Type Comments

numeric counter limit uint8

shader transparent chicago extended flags bitfield

Flag	Mask	Comments
alpha tested	`0x1`
decal	`0x2`	Makes the shader render with a slight depth bias toward the camera to prevent Z-fighting. Use this flag for light planes that will be placed at very small offsets from the surface behind them. Avoid using shaders with this flag where they're placed behind greates or embedded within geometric details, as it will sometimes sort incorrectly against them when viewed at a distance.
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`	The faces do not fade by viewing angle.
fade when perpendicular	`0x1`	The faces fade out when viewed edge-on.
fade when parallel	`0x2`	The faces fade out when viewed flat to the camera.

framebuffer fade source enum

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

lens flare spacing

float

Unit: world units

lens flare TagDependency: lens_flare

extra layers

Block

HEK max count: 4

Warning: Using a shader with extra layers on an object with transparent self occlusion enabled may cause Sapien and Standalone to crash if there are too many overlapping faces from the viewing angle.

Field	Type	Comments
shader	`TagDependency`: shader

maps 4 stage

Block

HEK max count: 4
Max: 4

Field Type Comments

flags bitfield

Flag	Mask	Comments
unfiltered	`0x1`
alpha replicate	`0x2`
u clamped	`0x4`	Texture coordinates outside the U 0-1 range will be clamped to the edges. See u animation function for caveats.
v clamped	`0x8`	Texture coordinates outside the V 0-1 range will be clamped to the edges. See u animation function for caveats.

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^?

map u scale float

map v scale float

map u offset float

map v offset float

map rotation float

mipmap bias

float

Min: 0
Max: 1

map TagDependency: bitmap

u animation source enum^?

u animation function

enum

Default: one

Horizontal animation function. The u and v animation functions default to 1, which results in effectively an additional map u offset and map v offset of 1. This causes some counterintuitive side effects. The u clamped and v clamped flags will not work properly, stretching the corner pixel across the entire canvas The rotation animation functions will behave unexpectedly as well, with 1 added to the rotation animation center coordinates. It is recommended to set the function to 0 if these features are being used.

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

float

Unit: seconds
Default: 1

u animation phase float

u animation scale

float

Unit: world units
Default: 1

v animation source enum^?

v animation function

enum^?

Default: one

Vertical animation function. See u animation function for caveats.

v animation period

float

Unit: seconds
Default: 1

v animation phase float

v animation scale

float

Unit: world units
Default: 1

rotation animation source enum^?

rotation animation function enum^?

rotation animation period

float

Unit: seconds
Default: 1

rotation animation phase float

rotation animation scale

float

Unit: degrees
Default: 360

rotation animation center

Point2D

Coordinates for the center of map rotation. Note that these coordinates may be offset unintuitively if u animation function and v animation function are not zero.

Field	Type	Comments
x	`float`
y	`float`

maps 2 stage

Block^?

HEK max count: 2
Max: 2

This block is used instead of maps 4 stage on older video hardware.

extra flags bitfield

Flag	Mask	Comments
don't fade active camouflage	`0x1`
numeric countdown timer	`0x2`
custom edition blending	`0x4`	Custom edition originally had an incorrect implementation of the multiply and double multiply framebuffer blend functions for transparent shaders which made fully dark pixels transparent. MCC is fixed but this flag allows modders to use custom edition's blending, which can help when porting legacy tags to the updated engine.

Acknowledgements

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

Jakey (Explaining purpose of this tag)
Kavawuvi (Invader tag definitions)
MosesOfEgypt (Tag structure research)