A Data Driven Factory

• I am still not happy with my factory.
  • I don't like editing things in game
  • Especially creating large lists.
  • Like the different magic items I might have.
• I added the Megascans Vegetables pack to my project
  • They were free last year so I grabbed them.
  • 
  • I have had several people tell me that you should grab the free content each month.
  • They are $5.00 right now, but you don't need them.
  • I have no artistic talent, so I have several of these that I use.
• So I am going to create a data driven factory.
  • This will rely on a CSV file that lists
    • The Name of the item.
    • The Description of the item.
    • The price of the item
    • The Type (EN_PickupType) of the item
    • The Path to the mesh
    • The path to the material the mesh uses.
  • I did this in excel.
    • 
    • Make sure that there are column headings
    • Spelled correctly.
    • I also ran the spell checker, but perhaps not enough.
    • Adding the Mesh and Material Data
      • Just find the asset
      • And right click
      • Select Copy Reference
      • 
    • The save-as csv somewhere in the project area
    • 
• A data table
  • Unreal has a tool to read csv files directly into an array of structures.
  • This is called a data table.
  • To star with, It needs a struct
  • So I built a ST_VeggieList
    • Note it contains a Static Mesh and a Material Instance.
    • 
  • Next I created Data Table Veggie_Data
    • A Basic Reference
    • Right click in the content browser and select Miscellaneous -> DataTable
    • 
    • It wants to know the associated struct, so give it the one your just created.
    • 
    • You will need to associate the csv file with this object, so click on Data Table Details
    • 
    • and browse to the file
    • 
    • You may need to click on reimport
    • And you certainly must do this every time you change the file.
    • 
• Now we need to add the new type, BP_Pickup_Veggie
  • Three variables
    • A Name and Description of type String
    • A Price of type int.
  • A fairly standard Pickup function
  • 
  • I added a SetupVeggie function to set all of the values.
    • This takes a ST_VeggieList as input
    • And returns the veggie for convenience.
    • 
• I added this type to the enumerator BP_PickupType
  • 
• Which instantly broke the factory
  • I needed to update the ClassListArray (I dislike this)
  • And all of the switches and selects had a new, unconnected item.
  • Since constructing a veggie is complex
  • And a new factory is the right way to do this, I added a veggie factory.
    • I really should have a base class ItemFactory that I am deriving these all from.
    • But I did not do that
    • So I just created a new BP_VeggieFactory
    • Two Functions
      • NewVeggie
        • 
      • GetRandomVeggie
        • 
        • Note, this calls GetDataTableRowNames
          • Which returns the names of the rows in an array.
        • Silly me, I found the Random ArrayItem function
        • And the Get Data Table Row function
  • I added a reference to one of these factories and created it in the main factory
    • 
  • And called it in the NewItem method
    • 
• Finally,
  • I couldn't stand the bug introduced when a new enumerator is added
  • So I added a check at the end of begin play in the base factory
    • 
  • And a warning in the enum list.
    • 
• I made two more "stores"
  • One that asks for an item from a list of items.
  • One that places items in fixed positions and restocks after the player exits.