A material defined by a custom [Shader] program and the values of its shader parameters. A material that uses a custom [Shader] program to render visual items (canvas items, meshes, skies, fog), or to process particles. Compared to other materials, [ShaderMaterial] gives deeper control over the generated shader code. For more information, see the shaders documentation index below. Multiple [ShaderMaterial]s can use the same shader and configure different values for the shader uniforms. [b]Note:[/b] For performance reasons, the [signal Resource.changed] signal is only emitted when the [member Resource.resource_name] changes. Only in editor, it is also emitted for [member shader] changes. $DOCS_URL/tutorials/shaders/index.html Returns the current value set for this material of a uniform in the shader. Changes the value set for this material of a uniform in the shader. [b]Note:[/b] [param param] is case-sensitive and must match the name of the uniform in the code exactly (not the capitalized name in the inspector). [b]Note:[/b] Changes to the shader uniform will be effective on all instances using this [ShaderMaterial]. To prevent this, use per-instance uniforms with [method GeometryInstance3D.set_instance_shader_parameter] or duplicate the [ShaderMaterial] resource using [method Resource.duplicate]. Per-instance uniforms allow for better shader reuse and are therefore faster, so they should be preferred over duplicating the [ShaderMaterial] when possible. The [Shader] program used to render this material.