Layer RGBA

The layer_RGBA shader can be used to linearly layer up to eight shaders together, enabling you to create complex shading effects. Layers are applied in order (bottom to top) according to a blending mode specified in the operation. The layer alpha can optionally be a separate input. A use for this shader could include adding text to an image for example.

Enable (1-8)

Enable/disable the layer entirely.

Name (1-8)

Layer name.

Input (1-8)

Input value for Layer.

Mix (1-8)

Controls the amount of blending between shaders.


0	0.5	1 (default)

You may need to insert a range shader when connecting a bitmap to mix.

Operation (1-8)

The blending mode for the current layer. They emulate all of Nuke and Photoshop's modes. In the formulas, A (layer_1) is the upstream intermediate result, and B (layer_2) is the current layer.

Click here to view the list of operations

overwrite: B
atop: A * B.a + B * (1 - A.a)
average: (A + B) / 2
cojoint_over: A if A.a > B.a else A + B * (1 - A.a) /B.a
color_burn: 1 - (1 - A) / B
color_dodge: A/ (1 - B)
difference: abs(A - B)
disjoint_over: A + B * (1 - A.a) / B.a, A + B if A.a + B.a < 1
divide: A / B, 0 if A and B < 0, else A if B < epsilon
exclusion: A + B - 2 * A * B
from: B - A
geometric: 2 * A * B / (A + B)
glow: B² / (1 - A)
hard_light: 1 - 2 * (1 - A) * (1 - B), 2 * A * B if A < 0.5
hard_mix: vivid_light(A, B) < 0.5 ? 0 : 1
hypot_diagonal: √(A² + B²)
in: A * B.a
linear_light: (B< 0.5) ? A + 2* B- 1: A + 2 * (B - 0.5)
mask: B * A.a
matte: A * A.a + B * (1 - A.a)
max: max(A, B)
min: min(A, B)
minus: A - B
multiply: A * B, A if A and B < 0
negation: 1 - abs(1 - A - B)
out: A * (1 - B.a)
over: A + B * (1 - A.a)
overlay: hardlight(B, A)
phoenix: min(A, B) - max(A, B) +1
pin_light: B < 0.5 ? min(A, 2 * B) : max(A, 2 * (B - 0.5)
plus: A + B
reflect: A² / (1 - B)
screen: A + B - A * B if A and B in 0..1, else max(A, B)
soft_light: Softer version of hard_light
stencil: B * (1 - A.a)
subtract: A + B - 1
under: A * (1 - B.a) + B
vivid_light: B < 0.5 ? color_burn(A, 2 * B) : color_dodge(A, 2* (B - 0.5)
xor: A * (1 - B.a) + B * (1 - A.a)


Atop: A * B.a + B * (1 - A.a)	Average: (A + B) / 2	Cojoint Over: A if A.a > B.a else A + B * (1 - A.a) /B.a	Color Burn: 1 - (1 - A) / B

Color Dodge: A/ (1 - B)	Difference: abs(A - B)	Disjoint Over: A + B * (1 - A.a) / B.a, A + B if A.a + B.a < 1	Divide: A / B, 0 if A and B < 0, else A if B < epsilon

Exclusion: A + B - 2 * A * B	From: B - A	Geometric: 2 * A * B / (A + B)	Glow: B2 / (1 - A)

Hard Light: 1 - 2 * (1 - A) * (1 - B), 2 * A * B if A < 0.5	Hard Light: 1 - 2 * (1 - A) * (1 - B), 2 * A * B if A < 0.5	Hypot Diagonal: hypot_diagonal: √(A2 + B2)	In: in: A * B.a

Linear Light: (B< 0.5) ? A + 2* B- 1: A + 2 * (B - 0.5)	Mask: B * A.a	Matte: A * A.a + B * (1 - A.a)	Max: max(A, B)

Min: min(A, B)	Minus: A - B	Multiply: A * B, A if A and B < 0	Negation: 1 - abs(1 - A - B)

Out: A * (1 - B.a)	Over: A + B * (1 - A.a)	Overlay: hardlight(B, A)	Overwrite: B

Phoenix: min(A, B) - max(A, B) +1	Pin Light: B < 0.5 ? min(A, 2 * B) : max(A, 2 * (B - 0.5)	Plus: A + B	Reflect: A2 / (1 - B)

Screen: A + B - A * B if A and B in 0..1, else max(A, B)	Soft Light: Softer version of hard_light	Stencil: B * (1 - A.a)	Subtract: A + B - 1

Under: A * (1 - B.a) + B	Vivid Light: B < 0.5 ? color_burn(A, 2 * B) : color_dodge(A, 2* (B - 0.5)	XOR: A * (1 - B.a) + B * (1 - A.a)

Normal Map

It is possible to blend multiple normal maps using the normal map blending operation.


Normal map->Layer 1 Input	Normal map->Layer 2 Input	Normal map 1 & 2 combined	Rendered result

Alpha Operation (1-8)

Optional alpha value for Layer.

Result: The alpha is computed in the same way as the other color channels (follows the "operation" for the RGB channel).

Preserve: Keeps the old alpha value ( A.a ).

Overwrite: The alpha channel is overwritten by the alpha of the current layer ( B.a ).

Mask: Calculated as: A.a + B.a - A.a * B.a.


Atop	Average	Cojoint Over	Color Burn

Color Dodge	Difference	Disjoint Over	Divide

Exclusion	From	Geometric	Glow

Hard Light	Hard Mix	Hypot Diagonal	In

Linear Light	Mask	Matte	Max

Min	Minus	Multiply	Negation

Out	Over	Overlay	Overwrite

Phoenix	Pin Light	Plus	Reflect

Screen	Soft Light	Stencil	Subtract

Under	Vivid Light	XOR