TypeScript type guard: narrows a Material to ShaderMaterial when it belongs to
the shader family (see getMaterialFamily). This also covers materials built on top of
createShaderMaterial, such as the grid material. A MaterialView over a shader
source also passes, since it inherits every shader property through its prototype chain.
TypeScript type guard: narrows a Material to ShaderMaterial when it belongs to the shader family (see getMaterialFamily). This also covers materials built on top of createShaderMaterial, such as the grid material. A MaterialView over a shader source also passes, since it inherits every shader property through its prototype chain.