Visual Shader Graph Set Default Texture to specific value

Godot Version



The shader graph only gives white, black, and transparent as options for a default value. However, in the case of an ORM texture, the USD and glTF standard for packing pbr textures packing occlusion, roughness, and metallic into the Red, green and blue channels respectively. I would like the default texture to be one with 1,0.5,0 rgb values. In other software, I have done this with another option to reference a texture image as the default, but Godot does not seem to have this option.

Is there a potential workaround or proper way to set up a custom texture or custom values beyond the three intial options?