gzdoom/wadsrc/static/shaders/scene/material_pbr.glsl

void SetupMaterial(inout Material material)
{
	SetMaterialProps(material, vTexCoord.st);
	material.Metallic = texture(metallictexture, vTexCoord.st).r;
	material.Roughness = texture(roughnesstexture, vTexCoord.st).r;
	material.AO = texture(aotexture, vTexCoord.st).r;
}