Now, we’ll add recipes to the game. Most of this code should look similar to what we do for Quests – a model, a factory, adding a list property to the Player class, and displaying the recipes in the UI.
Step 1: Modify Engine\Factories\ItemFactory.cs
Add the ingredients to make our healthy granola bar.
I added three new miscellaneous items (oats, honey, and raisins) on lines 23-25.
ItemFactory.cs
using System.Collections.Generic;
using System.Linq;
using Engine.Actions;
using Engine.Models;
namespace Engine.Factories
{
public static class ItemFactory
{
private static readonly List<GameItem> _standardGameItems = new List<GameItem>();
static ItemFactory()
{
BuildWeapon(1001, "Pointy Stick", 1, 1, 2);
BuildWeapon(1002, "Rusty Sword", 5, 1, 3);
BuildWeapon(1501, "Snake fangs", 0, 0, 2);
BuildWeapon(1502, "Rat claws", 0, 0, 2);
BuildWeapon(1503, "Spider fangs", 0, 0, 4);
BuildHealingItem(2001, "Granola bar", 5, 2);
BuildMiscellaneousItem(3001, "Oats", 1);
BuildMiscellaneousItem(3002, "Honey", 2);
BuildMiscellaneousItem(3003, "Raisins", 2);
BuildMiscellaneousItem(9001, "Snake fang", 1);
BuildMiscellaneousItem(9002, "Snakeskin", 2);
BuildMiscellaneousItem(9003, "Rat tail", 1);
BuildMiscellaneousItem(9004, "Rat fur", 2);
BuildMiscellaneousItem(9005, "Spider fang", 1);
BuildMiscellaneousItem(9006, "Spider silk", 2);
}
public static GameItem CreateGameItem(int itemTypeID)
{
return _standardGameItems.FirstOrDefault(item => item.ItemTypeID == itemTypeID)?.Clone();
}
private static void BuildMiscellaneousItem(int id, string name, int price)
{
_standardGameItems.Add(new GameItem(GameItem.ItemCategory.Miscellaneous, id, name, price));
}
private static void BuildWeapon(int id, string name, int price,
int minimumDamage, int maximumDamage)
{
GameItem weapon = new GameItem(GameItem.ItemCategory.Weapon, id, name, price, true);
weapon.Action = new AttackWithWeapon(weapon, minimumDamage, maximumDamage);
_standardGameItems.Add(weapon);
}
private static void BuildHealingItem(int id, string name, int price, int hitPointsToHeal)
{
GameItem item = new GameItem(GameItem.ItemCategory.Consumable, id, name, price);
item.Action = new Heal(item, hitPointsToHeal);
_standardGameItems.Add(item);
}
}
}
Step 2: Create Engine\Models\Recipe.cs
This class holds a list of ingredient items (and their quantities) that need to be combined and the Output items and quantities that are created by the recipe.
I have the Output as a List of ItemQuantity objects, so we can create multiple items and have “waste” items that are a by-product of our crafting.
There are also two helper functions – AddIngredient and AddOutputItem – for us to populate the Ingredients and OutputItems properties without allowing duplicate items.
Recipe.cs
using System.Collections.Generic;
using System.Linq;
namespace Engine.Models
{
public class Recipe
{
public int ID { get; }
public string Name { get; }
public List<ItemQuantity> Ingredients { get; } = new List<ItemQuantity>();
public List<ItemQuantity> OutputItems { get; } = new List<ItemQuantity>();
public Recipe(int id, string name)
{
ID = id;
Name = name;
}
public void AddIngredient(int itemID, int quantity)
{
if(!Ingredients.Any(x => x.ItemID == itemID))
{
Ingredients.Add(new ItemQuantity(itemID, quantity));
}
}
public void AddOutputItem(int itemID, int quantity)
{
if(!OutputItems.Any(x => x.ItemID == itemID))
{
OutputItems.Add(new ItemQuantity(itemID, quantity));
}
}
}
}
Step 3: Create Engine\Factories\RecipeFactory.cs
The recipe factory class is like the quest factory. We create a recipe, add it to our private variable, and have a “GetByID” function to get the standard Recipe object from this factory.
RecipeFactory.cs
using System.Collections.Generic;
using System.Linq;
using Engine.Models;
namespace Engine.Factories
{
public static class RecipeFactory
{
private static readonly List<Recipe> _recipes = new List<Recipe>();
static RecipeFactory()
{
Recipe granolaBar = new Recipe(1, "Granola bar");
granolaBar.AddIngredient(3001, 1);
granolaBar.AddIngredient(3002, 1);
granolaBar.AddIngredient(3003, 1);
granolaBar.AddOutputItem(2001, 1);
_recipes.Add(granolaBar);
}
public static Recipe RecipeByID(int id)
{
return _recipes.FirstOrDefault(x => x.ID == id);
}
}
}
Step 4: Modify Engine\Models\Player.cs
Modify the Player class, to hold a list of the Recipes they know.
Add a new Recipes property on line 40 and initialize it with an empty ObservableList
Add a new Recipes property on line 40 and initialize it with an empty ObservableList<Recipe> on line 54 of the constructor.
I also added a helper function LearnRecipe on lines 75-81. This checks that the Player doesn’t already have the recipe before adding it to their Recipes property.
Player.cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
namespace Engine.Models
{
public class Player : LivingEntity
{
#region Properties
private string _characterClass;
private int _experiencePoints;
public string CharacterClass
{
get { return _characterClass; }
set
{
_characterClass = value;
OnPropertyChanged();
}
}
public int ExperiencePoints
{
get { return _experiencePoints; }
private set
{
_experiencePoints = value;
OnPropertyChanged();
SetLevelAndMaximumHitPoints();
}
}
public ObservableCollection<QuestStatus> Quests { get; }
public ObservableCollection<Recipe> Recipes { get; }
#endregion
public event EventHandler OnLeveledUp;
public Player(string name, string characterClass, int experiencePoints,
int maximumHitPoints, int currentHitPoints, int gold) :
base(name, maximumHitPoints, currentHitPoints, gold)
{
CharacterClass = characterClass;
ExperiencePoints = experiencePoints;
Quests = new ObservableCollection<QuestStatus>();
Recipes = new ObservableCollection<Recipe>();
}
public bool HasAllTheseItems(List<ItemQuantity> items)
{
foreach (ItemQuantity item in items)
{
if (Inventory.Count(i => i.ItemTypeID == item.ItemID) < item.Quantity)
{
return false;
}
}
return true;
}
public void AddExperience(int experiencePoints)
{
ExperiencePoints += experiencePoints;
}
public void LearnRecipe(Recipe recipe)
{
if(!Recipes.Any(r => r.ID == recipe.ID))
{
Recipes.Add(recipe);
}
}
private void SetLevelAndMaximumHitPoints()
{
int originalLevel = Level;
Level = (ExperiencePoints / 100) + 1;
if (Level != originalLevel)
{
MaximumHitPoints = Level * 10;
OnLeveledUp?.Invoke(this, System.EventArgs.Empty);
}
}
}
}
Step 5: Modify Engine\ViewModels\GameSession.cs
Let’s give the player the granola bar recipe as their first recipe.
In the constructor, on line 133, get the granola bar recipe from the RecipeFactory and have the Player learn it through the LearnRecipe function.
GameSession.cs
using System;
using System.Linq;
using Engine.EventArgs;
using Engine.Factories;
using Engine.Models;
namespace Engine.ViewModels
{
public class GameSession : BaseNotificationClass
{
public event EventHandler<GameMessageEventArgs> OnMessageRaised;
#region Properties
private Player _currentPlayer;
private Location _currentLocation;
private Monster _currentMonster;
private Trader _currentTrader;
public World CurrentWorld { get; }
public Player CurrentPlayer
{
get { return _currentPlayer; }
set
{
if(_currentPlayer != null)
{
_currentPlayer.OnActionPerformed -= OnCurrentPlayerPerformedAction;
_currentPlayer.OnLeveledUp -= OnCurrentPlayerLeveledUp;
_currentPlayer.OnKilled -= OnCurrentPlayerKilled;
}
_currentPlayer = value;
if (_currentPlayer != null)
{
_currentPlayer.OnActionPerformed += OnCurrentPlayerPerformedAction;
_currentPlayer.OnLeveledUp += OnCurrentPlayerLeveledUp;
_currentPlayer.OnKilled += OnCurrentPlayerKilled;
}
}
}
public Location CurrentLocation
{
get { return _currentLocation; }
set
{
_currentLocation = value;
OnPropertyChanged();
OnPropertyChanged(nameof(HasLocationToNorth));
OnPropertyChanged(nameof(HasLocationToEast));
OnPropertyChanged(nameof(HasLocationToWest));
OnPropertyChanged(nameof(HasLocationToSouth));
CompleteQuestsAtLocation();
GivePlayerQuestsAtLocation();
GetMonsterAtLocation();
CurrentTrader = CurrentLocation.TraderHere;
}
}
public Monster CurrentMonster
{
get { return _currentMonster; }
set
{
if(_currentMonster != null)
{
_currentMonster.OnActionPerformed -= OnCurrentMonsterPerformedAction;
_currentMonster.OnKilled -= OnCurrentMonsterKilled;
}
_currentMonster = value;
if(_currentMonster != null)
{
_currentMonster.OnActionPerformed += OnCurrentMonsterPerformedAction;
_currentMonster.OnKilled += OnCurrentMonsterKilled;
RaiseMessage("");
RaiseMessage($"You see a {CurrentMonster.Name} here!");
}
OnPropertyChanged();
OnPropertyChanged(nameof(HasMonster));
}
}
public Trader CurrentTrader
{
get { return _currentTrader; }
set
{
_currentTrader = value;
OnPropertyChanged();
OnPropertyChanged(nameof(HasTrader));
}
}
public bool HasLocationToNorth =>
CurrentWorld.LocationAt(CurrentLocation.XCoordinate, CurrentLocation.YCoordinate + 1) != null;
public bool HasLocationToEast =>
CurrentWorld.LocationAt(CurrentLocation.XCoordinate + 1, CurrentLocation.YCoordinate) != null;
public bool HasLocationToSouth =>
CurrentWorld.LocationAt(CurrentLocation.XCoordinate, CurrentLocation.YCoordinate - 1) != null;
public bool HasLocationToWest =>
CurrentWorld.LocationAt(CurrentLocation.XCoordinate - 1, CurrentLocation.YCoordinate) != null;
public bool HasMonster => CurrentMonster != null;
public bool HasTrader => CurrentTrader != null;
#endregion
public GameSession()
{
CurrentPlayer = new Player("Scott", "Fighter", 0, 10, 10, 1000000);
if (!CurrentPlayer.Weapons.Any())
{
CurrentPlayer.AddItemToInventory(ItemFactory.CreateGameItem(1001));
}
CurrentPlayer.AddItemToInventory(ItemFactory.CreateGameItem(2001));
CurrentPlayer.LearnRecipe(RecipeFactory.RecipeByID(1));
CurrentWorld = WorldFactory.CreateWorld();
CurrentLocation = CurrentWorld.LocationAt(0, 0);
}
public void MoveNorth()
{
if(HasLocationToNorth)
{
CurrentLocation = CurrentWorld.LocationAt(CurrentLocation.XCoordinate, CurrentLocation.YCoordinate + 1);
}
}
public void MoveEast()
{
if(HasLocationToEast)
{
CurrentLocation = CurrentWorld.LocationAt(CurrentLocation.XCoordinate + 1, CurrentLocation.YCoordinate);
}
}
public void MoveSouth()
{
if(HasLocationToSouth)
{
CurrentLocation = CurrentWorld.LocationAt(CurrentLocation.XCoordinate, CurrentLocation.YCoordinate - 1);
}
}
public void MoveWest()
{
if(HasLocationToWest)
{
CurrentLocation = CurrentWorld.LocationAt(CurrentLocation.XCoordinate - 1, CurrentLocation.YCoordinate);
}
}
private void CompleteQuestsAtLocation()
{
foreach(Quest quest in CurrentLocation.QuestsAvailableHere)
{
QuestStatus questToComplete =
CurrentPlayer.Quests.FirstOrDefault(q => q.PlayerQuest.ID == quest.ID &&
!q.IsCompleted);
if(questToComplete != null)
{
if(CurrentPlayer.HasAllTheseItems(quest.ItemsToComplete))
{
// Remove the quest completion items from the player's inventory
foreach (ItemQuantity itemQuantity in quest.ItemsToComplete)
{
for(int i = 0; i < itemQuantity.Quantity; i++)
{
CurrentPlayer.RemoveItemFromInventory(CurrentPlayer.Inventory.First(item => item.ItemTypeID == itemQuantity.ItemID));
}
}
RaiseMessage("");
RaiseMessage($"You completed the '{quest.Name}' quest");
// Give the player the quest rewards
RaiseMessage($"You receive {quest.RewardExperiencePoints} experience points");
CurrentPlayer.AddExperience(quest.RewardExperiencePoints);
RaiseMessage($"You receive {quest.RewardGold} gold");
CurrentPlayer.ReceiveGold(quest.RewardGold);
foreach(ItemQuantity itemQuantity in quest.RewardItems)
{
GameItem rewardItem = ItemFactory.CreateGameItem(itemQuantity.ItemID);
RaiseMessage($"You receive a {rewardItem.Name}");
CurrentPlayer.AddItemToInventory(rewardItem);
}
// Mark the Quest as completed
questToComplete.IsCompleted = true;
}
}
}
}
private void GivePlayerQuestsAtLocation()
{
foreach(Quest quest in CurrentLocation.QuestsAvailableHere)
{
if(!CurrentPlayer.Quests.Any(q => q.PlayerQuest.ID == quest.ID))
{
CurrentPlayer.Quests.Add(new QuestStatus(quest));
RaiseMessage("");
RaiseMessage($"You receive the '{quest.Name}' quest");
RaiseMessage(quest.Description);
RaiseMessage("Return with:");
foreach(ItemQuantity itemQuantity in quest.ItemsToComplete)
{
RaiseMessage($" {itemQuantity.Quantity} {ItemFactory.CreateGameItem(itemQuantity.ItemID).Name}");
}
RaiseMessage("And you will receive:");
RaiseMessage($" {quest.RewardExperiencePoints} experience points");
RaiseMessage($" {quest.RewardGold} gold");
foreach(ItemQuantity itemQuantity in quest.RewardItems)
{
RaiseMessage($" {itemQuantity.Quantity} {ItemFactory.CreateGameItem(itemQuantity.ItemID).Name}");
}
}
}
}
private void GetMonsterAtLocation()
{
CurrentMonster = CurrentLocation.GetMonster();
}
public void AttackCurrentMonster()
{
if(CurrentPlayer.CurrentWeapon == null)
{
RaiseMessage("You must select a weapon, to attack.");
return;
}
CurrentPlayer.UseCurrentWeaponOn(CurrentMonster);
if(CurrentMonster.IsDead)
{
// Get another monster to fight
GetMonsterAtLocation();
}
else
{
CurrentMonster.UseCurrentWeaponOn(CurrentPlayer);
}
}
public void UseCurrentConsumable()
{
CurrentPlayer.UseCurrentConsumable();
}
private void OnCurrentPlayerPerformedAction(object sender, string result)
{
RaiseMessage(result);
}
private void OnCurrentMonsterPerformedAction(object sender, string result)
{
RaiseMessage(result);
}
private void OnCurrentPlayerKilled(object sender, System.EventArgs eventArgs)
{
RaiseMessage("");
RaiseMessage("You have been killed.");
CurrentLocation = CurrentWorld.LocationAt(0, -1);
CurrentPlayer.CompletelyHeal();
}
private void OnCurrentMonsterKilled(object sender, System.EventArgs eventArgs)
{
RaiseMessage("");
RaiseMessage($"You defeated the {CurrentMonster.Name}!");
RaiseMessage($"You receive {CurrentMonster.RewardExperiencePoints} experience points.");
CurrentPlayer.AddExperience(CurrentMonster.RewardExperiencePoints);
RaiseMessage($"You receive {CurrentMonster.Gold} gold.");
CurrentPlayer.ReceiveGold(CurrentMonster.Gold);
foreach(GameItem gameItem in CurrentMonster.Inventory)
{
RaiseMessage($"You receive one {gameItem.Name}.");
CurrentPlayer.AddItemToInventory(gameItem);
}
}
private void OnCurrentPlayerLeveledUp(object sender, System.EventArgs eventArgs)
{
RaiseMessage($"You are now level {CurrentPlayer.Level}!");
}
private void RaiseMessage(string message)
{
OnMessageRaised?.Invoke(this, new GameMessageEventArgs(message));
}
}
}
Step 6: Modify WPFUI\MainWindow.xaml
Finally, we’ll add the player’s known recipe list to the UI. We’ll place it in the lower-left section of the screen as a new tab item.
NOTE: There is a problem with this code if you run the game and click on a recipe name in the datagrid. You would get the error message: System.InvalidOperationException: ‘A TwoWay or OneWayToSource binding cannot work on the read-only property ‘Name’ of type ‘Engine.Models.Recipe’.’
There is a fix for that in lesson 13.2, when we change the Binding to “{Binding Name, Mode=OneWay}”
MainWindow.xaml (lines 201-211)
<TabItem Header="Recipes">
<DataGrid ItemsSource="{Binding CurrentPlayer.Recipes}"
AutoGenerateColumns="False"
HeadersVisibility="Column">
<DataGrid.Columns>
<DataGridTextColumn Header="Name"
Binding="{Binding Name}"
Width="*"/>
</DataGrid.Columns>
</DataGrid>
</TabItem>
Step 7: Run your unit tests and play the game, to test the latest changes.
In the next lesson, we’ll add the ability to craft, so the player can finally make their first granola bar.
NEXT LESSON: Lesson 12.8: Crafting items with recipes
PREVIOUS LESSON: Lesson 12.6: Refactoring after adding Actions