Toggle and check shader keywords in a script

Check if a keyword is enabled or disabled

When a global and local shaderA program that runs on the GPU. More info
See in Glossary keyword with the same name have different states, Unity uses the isOverridable property of a LocalKeyword to determine whether the keyword is enabled or disabled for an individual material or compute shader. isOverridable is true if the keyword was declared with global scope, and false if it was declared with local scope.

• When isOverridable is true: If a global keyword with the same name exists and is enabled, Unity uses the state of the global keyword. Otherwise, Unity uses the state of the local keyword.
• When isOverridable is false: Unity always uses the state of the local keyword.

Therefore, to understand whether a shader keyword is enabled or disabled for an individual material or compute shader, you must examine the state of the isOverridable property and the global and/or local keyword state.

This example demonstrates how to check whether Unity considers a keyword enabled or disabled for a material:

using UnityEngine;
using UnityEngine.Rendering;

public class KeywordExample : MonoBehaviour
{
    public Material material;

    void Start()
    {
        CheckShaderKeywordState();
    }

    void CheckShaderKeywordState()
    {
        // Get the instance of the Shader class that the material uses
        var shader = material.shader;

        // Get all the local keywords that affect the Shader
        var keywordSpace = shader.keywordSpace;

        // Iterate over the local keywords
        foreach (var localKeyword in keywordSpace.keywords)
        {
            // If the local keyword is overridable (i.e., it was declared with a global scope),
            // and a global keyword with the same name exists and is enabled,
            // then Unity uses the global keyword state
            if (localKeyword.isOverridable && Shader.IsKeywordEnabled(localKeyword.name))
            {
                Debug.Log("Local keyword with name of " + localKeyword.name + " is overridden by a global keyword, and is enabled");
            }
            // Otherwise, Unity uses the local keyword state
            else
            {
                var state = material.IsKeywordEnabled(localKeyword) ? "enabled" : "disabled";
                Debug.Log("Local keyword with name of " + localKeyword.name + " is " + state);
            }            
        }
    }
}

Enabling and disabling shader keywords

To check whether a local keyword is enabled for a graphics shader, use Material.IsKeywordEnabled or Material.EnableKeyword. For a compute shader, use ComputeShader.IsKeywordEnabled, or ComputeShader.EnableKeyword.

To check whether a global keyword is enabled, use Shader.IsKeywordEnabled or Shader.EnableKeyword or ComputeShader.enabledKeywords.

To enable or disable a local shader keyword for a graphics shader, use Material.SetKeyword, Material.EnableKeyword, or Material.DisableKeyword. For a compute shader, use ComputeShader.SetKeyword, ComputeShader.EnableKeyword, or ComputeShader.DisableKeyword.

To enable or disable a global shader keyword, use Shader.SetKeyword, ComputeShader.EnableKeyword, or ComputeShader.DisableKeyword.

To enable or disable a local or global keyword with a Command Buffer, use CommandBuffer.EnableKeyword, or CommandBuffer.DisableKeyword .

Note: When you enable or disable keywords that work with shader variants, Unity uses different shader variants. Changing shader variants at runtime can impact performance. If a change in keywords requires a variant to be used for the first time, it can lead to hitches while the graphics driver prepares the shader program. This can be a particular problem for large or complex shaders, or if a global keyword state change affects multiple shaders. To avoid this, if you use keywords with shader variants, ensure that you consider keyword variants in your shader loading and prewarming strategy. For more information, see Shader loading.

Check if a keyword was declared for dynamic branching

In Unity, you can use shader keywords with shader variants, or you can use them with dynamic branching. You decide when you declare the keywords.

The isDynamic property of a LocalKeyword indicates whether the keyword was declared for use with dynamic branching in the shader source file. It is true if the keyword was declared for use with dynamic branching, and false if it was declared for use with shader variants.

Additional resources

• Shader keyword scope fundamentals