ohdear.rb

# Returns a hash mapping image paths to arrays of the assets referencing them
def image_usage
  {}.tap do |usage|
    asset_types = app.metadata.by_name.values + @class_by_ref.values

    image_properties_by_type = asset_types.flat_map do |type|
      type.properties.values
          .select{ |property| property.type=='Image' || property.type == 'Texture' }
          .map{ |property| [type,property] }
    end.group_by(&:first).tap{ |x| x.each{ |t,a| a.map!(&:last) } }

    assets.each do |asset|
      if properties = image_properties_by_type[asset.class]
        properties.each do |property|
          asset[property.name].values.compact.each do |value|
            value = value['sourcepath'] if property.type=='Image'
            usage[value] ||= []
            usage[value] << asset
          end
        end
      end
    end
  end
end