Version: 2018.4
ShaderLab: SubShader
ShaderLab culling and depth testing

ShaderLab: Pass

The Pass block causes the geometry of a GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
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to be rendered once.


Pass { [Name and Tags] [RenderSetup] }

The basic Pass command contains a list of render state setup commands.

Name and tags

A Pass can define its Name and arbitrary number of TagsA reference word which you can assign to one or more GameObjects to help you identify GameObjects for scripting purposes. For example, you might define and “Edible” Tag for any item the player can eat in your game. More info
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. These are name/value strings that communicate the Pass’s intent to the renderingThe process of drawing graphics to the screen (or to a render texture). By default, the main camera in Unity renders its view to the screen. More info
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Render state set-up

A Pass sets up various states of the graphics hardware, such as whether alpha blending should be turned on or whether depth testing should be used.

The commands are as follows:


Cull Back | Front | Off

Set polygon culling mode.


ZTest (Less | Greater | LEqual | GEqual | Equal | NotEqual | Always)

Set depth bufferA memory store that holds the z-value depth of each pixel in an image, where the z-value is the depth for each rendered pixel from the projection plane. More info
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testing mode.


ZWrite On | Off

Set depth buffer writing mode.


Offset OffsetFactor, OffsetUnits

Set Z buffer depth offset. See documentation on Cull and Depth page for more details.

See documentation on Cull and Depth for more details on Cull, ZTest, ZWrite and Offset.


Blend sourceBlendMode destBlendMode
Blend sourceBlendMode destBlendMode, alphaSourceBlendMode alphaDestBlendMode
BlendOp colorOp
BlendOp colorOp, alphaOp
AlphaToMask On | Off

Sets alpha blending, alpha operation, and alpha-to-coverage modes. See documentation on Blending for more details.


ColorMask RGB | A | 0 | any combination of R, G, B, A

Set color channel writing mask. Writing ColorMask 0 turns off rendering to all color channels. Default mode is writing to all channels (RGBA), but for some special effects you might want to leave certain channels unmodified, or disable color writes completely.

When using multiple render target (MRT) rendering, it is possible to set up different color masks for each render target, by adding index (0–7) at the end. For example, ColorMask RGB 3 would make render target #3 write only to RGB channels.

Legacy fixed-function Shader commands

A number of commands are used for writing legacy “fixed-function style” ShadersA small script that contains the mathematical calculations and algorithms for calculating the Color of each pixel rendered, based on the lighting input and the Material configuration. More info
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. This is considered deprecated functionality, as writing Surface ShadersUnity’s code generation approach that makes it much easier to write lit shaders than using low level vertex/pixel shader programs. More info
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or Shader programs allows much more flexibility. However, for very simple Shaders, writing them in fixed-function style can sometimes be easier, so the commands are provided here. Note that all of the following commands are are ignored if you are not using fixed-function Shaders.

Fixed-function Lighting and Material

Lighting On | Off
Material { Material Block }
SeparateSpecular On | Off
Color Color-value
ColorMaterial AmbientAndDiffuse | Emission

All of these control fixed-function per-vertex Lighting: they turn it on, set up Material colors, turn on specular highlights, provide default color (if vertex Lighting is off), and controls how the meshThe main graphics primitive of Unity. Meshes make up a large part of your 3D worlds. Unity supports triangulated or Quadrangulated polygon meshes. Nurbs, Nurms, Subdiv surfaces must be converted to polygons. More info
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vertex colors affect Lighting. See documentation on MaterialsAn asset that defines how a surface should be rendered, by including references to the Textures it uses, tiling information, Color tints and more. The available options for a Material depend on which Shader the Material is using. More info
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for more details.

Fixed-function Fog

Fog { Fog Block }

Set fixed-function Fog parameters. See documentation onFogging for more details.

Fixed-function AlphaTest

AlphaTest (Less | Greater | LEqual | GEqual | Equal | NotEqual | Always) CutoffValue

Turns on fixed-function alpha testing. See documentation on alpha testing for more details.

Fixed-function Texture combiners

After the render state setup, use SetTexture commands to specify a number of Textures and their combining modes:

SetTexture textureProperty { combine options }


Shader passes interact with Unity’s rendering pipeline in several ways; for example, a Pass can indicate that it should only be used for deferred shadingA rendering path that places no limit on the number of lights that can affect a GameObject. All lights are evaluated per-pixel, which means that they all interact correctly with normal maps and so on. Additionally, all lights can have cookies and shadows. More info
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using the Tags command. Certain passes can also be executed multiple times on the same GameObject; for example, in forward renderingA rendering path that renders each object in one or more passes, depending on lights that affect the object. Lights themselves are also treated differently by Forward Rendering, depending on their settings and intensity. More info
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the “ForwardAdd” pass type is executed multiple times based on how many Lights are affecting the GameObject. See documentation on the Render Pipeline for more details.

See also

There are several special passes available for reusing common functionality or implementing various high-end effects:

  • UsePass includes named passes from another shader.
  • GrabPass grabs the contents of the screen into a Texture, for use in a later pass.
ShaderLab: SubShader
ShaderLab culling and depth testing