ShaderLab syntax: BindChannels
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ShaderLab syntax: BindChannels

BindChannels command allows you to specify how vertex data maps to the graphics hardware.

BindChannels has no effect when programmable vertex shaders are used, as in that case bindings are controlled by vertex shader inputs.

By default, Unity figures out the bindings for you, but in some cases you want custom ones to be used.

For example you could map the primary UV set to be used in the first texture stage and the secondary UV set to be used in the second texture stage; or tell the hardware that vertex colors should be taken into account.

Syntax

BindChannels { Bind "source", target }
Specifies that vertex data source maps to hardware target.

Source can be one of:

Target can be one of:

Details

Unity places some restrictions on which sources can be mapped to which targets. Source and target must match for Vertex, Normal, Tangent and Color. Texture coordinates from the mesh (Texcoord and Texcoord1) can be mapped into texture coordinate targets (Texcoord for all texture stages, or TexcoordN for a specific stage).

There are two typical use cases for BindChannels:

Examples

// Maps the first UV set to the first texture stage
// and the second UV set to the second texture stage
BindChannels {
   Bind "Vertex", vertex
   Bind "texcoord", texcoord0
   Bind "texcoord1", texcoord1
} 
// Maps the first UV set to all texture stages
// and uses vertex colors
BindChannels {
   Bind "Vertex", vertex
   Bind "texcoord", texcoord
   Bind "Color", color
}