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Unity Engine

Shader keywords workflow

Learn about defining shader keywords to create shaders that share some common code, but have different functionality when you enable or disable a keyword.
Read time 2 minutesLast updated 21 days ago
To control how shaders behave in different situations, use shader keywords. Each keyword acts as a toggle to change the shader's behavior.
You can use keywords to do the following:
  • Configure different settings for a material.
  • Make a shader work differently on different hardware.
  • Dynamically change the behavior of a shader at runtime.
Use the following steps:
  1. Declare a shader keyword, or a set of shader keywords.
  2. Use an 
    if
    statement to branch the shader code depending on the state of the keyword.
  3. Toggle the shader keyword to control which branch is active.

Declare a shader keyword

Declare a shader keyword, or a set of shader keywords, using a 
#pragma
statement. The following example defines a set of 2 keywords called 
RED
and 
GREEN
:
#pragma shader_feature RED GREEN
For more information, refer to Declare shader keywords.

Branch the shader code

Use an 
if
statement to make parts of your shader code execute based on the state of the keyword. For example, use the 
RED
and 
GREEN
keywords to control the color the shader outputs:
void frag() : SV_Target {    if (RED)    {        // Output red    }        else if (GREEN)    {        // Output green    }}
For more information, refer to Make shader behavior conditional on keywords.
Note
You can also use HLSL conditional statements like 
if
and preprocessor statements like 
#if
without using shader keywords.

Toggle the shader keyword

To control the shader from the Editor or at runtime, refer to the following:

Additional resources