StendhalDesign

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This small doc tries to create an agreement on what stendhal is about and what it needs to include. It considers the existing [[StendhalObjectives#Roadmap Roadmap|]] and tries to give a coherent vision of what we are trying to create.

Please use the Discussion tab (found in the menu at the top of the page) to query about things or make suggestions.

Plot

Stendhal's plot is to grow Sheep by taking them with you to the plains or forest to graze.
The task is not as simple as it may sound though, as you will have to protect them from hungry wolves! Use your skill, strength and wit to destroy the attackers.

Lambs must first be bought at a Farm and later sold at the Village when they are plump enough. For each Sheep you sell, when fully grown, you will get extra income.

You will need to spend your money on new weapons, armor and healing potions.

As you can see Stendhal is a minigame that will try to push and thus test everything related to a fully blown RPG:

  • task
  • actions
  • areas

If Arianne is a successful platform to get Stendhal working, the only issue is scaling up the result. :)

Design

Idea

The whole game area will look like:

http://arianne.sourceforge.net/wiki_images/Stendhal_Map.jpg

It is split in to 4 different areas to test the multizones feature of Arianne.
Players need to change zone in order to accomplish their task.

Our world is made of several entities: players, wolves, rats, sheeps, NPC. By describing each entity with use cases we will simplify later the coding stage.

Use cases description

We need to use several use cases to describe our game.

Player's user case

Player is an entity that play the game, it can move, chat, attack, heal.

  Player enter village in entry point
  Player moves to Farm zone

  Player talks with Sheep seller
    Player: Hi
    Seller: Greetings! How may I help you?
    Player: buy Sheep
    Seller: Do you want to buy a Sheep for 50 coins?
    Player: yes
    Seller: Thank you! Bye

  Player moves. Sheep follows Player.
  Player moves to plains
  Player moves around looking for food
  Player protect Sheep of wolves attacks

  When Sheep is big enough Player moves to Village
  Player talks with Sheep buyer
    Player: Hi
    Buyer: Greetings! How may I help you?
    Player: sell Sheep
    Buyer: Do you want to sell this Sheep for 73 coins?
    Player: yes
    Buyer: Thank you! Bye

  Player spend money in new Sheep and equipment
  * Armor
  * Weapon
  * Healing potions

Sheep seller's user case

This seller is a NPC entity that will sell us a sheep to grow it up and make money.

FOREVER do:
  Listen to Player

  If listen "Hi":
    Seller says "Greetings <Player>!"

  If listen "Buy Sheep" from Player:
    Seller says "Do you want to buy a Sheep for 50 coins?"

  If listen "yes" from Player:
    If Player money - 50 > 0:
      set Player money=Player money - 50
      Duplicate Sheep
      Make Sheep follows Player
  Say bye to Player
DONE

Sheep buyer's user case

This buyer is a NPC entity that will buy us our sheep.

FOREVER do:
  Listen to Player

  If listen "Hi":
    Seller says "Greetings <Player>!"

  If listen "Sell Sheep" from Player:
    Estimate Sheep value related to Sheep weight
    Seller says "Do you want to sell your Sheep for <estimated price> coins?"
  
  If listen "yes" from Player:
    set Player money=Player money + <estimated price>
    set Player XP=Player XP + 100 * Sheep Weight / 100
    Destroy Sheep
  
  Say bye to Player
DONE

Sheep's user case

Sheep is our key game concept. Sheeps must be grow up to earn money and buy stuff.

  Sheep is in Farm
  Player buys Sheep
  Sheep seller duplicates Sheep
  Sheep follows Player

  If Sheep finds food:
    Sheep moves to food
    Sheep eats food
    Sheep gains weight

  Player sells Sheep
  Sheep dissappear

Wolf's user case

Wolf is the compitive entity on Stendhal. They join to attack sheeps and often also players. They can kill a sheep in not a long time.

  Wolf moves
  If Wolf sees Sheep:
    Wolf attacks Sheep
  
  If Wolf is attacked:
    Wolf attacks Attacker

Rat's user case

Rat and Cave rats are creatures that will attack player to make it harder to grow the sheep up.

  Rat moves
  If Rat sees Player:
    Rat attacks Player
  
  If Rat is attacked:
    Rat attacks Attacker


Entities

The above user cases describe the need for the following entities in our system:

  • Sheep
  • Sheep seller
  • Sheep buyer
  • Wolf
  • Rat
  • Cave rat
  • Player
  • Food
  • Armor
  • Weapon
  • Healing potion

Let's describe each entity and its attributes and actions.

Sheep

A sheep has the following set of attributes:

  • x is the x-position of the sheep
  • y is the y-position of the sheep
  • dx is the x-speed of the sheep
  • dy is the y-speed of the sheep
  • hp is the life indicator of the sheep, when it reach 0 the sheep dies.
  • atk is the RP attack value. See RP rules
  • def is the RP defense value. See RP rules
  • xp is the RP experience value. See RP rules
  • weight is the weight indicator of the sheep, the more weight, the more expensive it is.

Sheep tasks should be:

  • follow
  • eat

The sheeps behaviour is mainly to follow its owner and look for food.
If the Sheep finds food, it will eat.
Sheep will runaway if attacked.

Creatures: Wolf, rat and Cave rat

Wolves, rats and cave rats have the following set of attributes:

  • x is the x-position of the wolf
  • y is the y-position of the wolf
  • dx is the x-speed of the wolf
  • dy is the y-speed of the wolf
  • hp is the life indicator of the wolf, when it reach 0 the wolf dies.
  • atk is the RP attack value. See RP rules
  • def is the RP defense value. See RP rules
  • xp is the RP experience value. See RP rules

Wolf ( and rat and cave rat ) tasks should be:

  • follow means that wolf follows an object using the shortest way to reach it.
  • attack means that wolf will try to damage the attacked object until its hp reach 0
    Another action will cancel attack task.
  • patrol means that wolf will move around a specified path.
  • chat means that wolf will start to shout 'auuuuuuu!'. Wolves will often understand this as a call.

Wolf ( and rat and cave rat ) behaviour consists of patrolling some assigned areas.
If the Wolf finds a Sheep, it will attack Sheep.
If the Wolf finds a Player, it will attack player.
If the Wolf is attacked, the Wolf returns the attacks.
If the Wolf is severly injured, the Wolf will runaway.

Sheep seller, Sheep buyer, Beggar

The buyer and seller have the following set of attributes:

  • x is the x-position of the NPC
  • y is the y-position of the NPC
  • dx is the x-speed of the NPC
  • dy is the y-speed of the NPC
  • hp is the life indicator of the NPC, when it reach 0 it is reset back to full.
  • atk is the RP attack value. See RP rules
  • def is the RP defense value. See RP rules
  • xp is the RP experience value. See RP rules
  • attending is the object_id of the player that is actually attending.

seller, buyer and beggar tasks would be:

  • patrol means that NPC will move around a specified path.

NPC behaviour consists of listening to people near them.
If person says "Hi", NPC faces person and generates conversation.

Player

The player has the following set of attributes:

  • x is the x-position of the player
  • y is the y-position of the player
  • dx is the x-speed of the player
  • dy is the y-speed of the player
  • hp is the life indicator of the Player, when it reach 0 the player dies. See Dead
  • atk is the RP attack value. See RP rules
  • def is the RP defense value. See RP rules
  • xp is the RP experience value. See RP rules
  • money is the quantity of money the player has.

It has three slots:

  • armor
  • left hand
  • right hand
  • backpack

Player tasks should be:

  • move means that player will change its dx, dy params to move.
  • attack means that player will try to damage the attacked object until its hp reach 0.
    Another action will cancel attack task.
  • chat means that player writes text to other players or NPCs

Food

Food has the following set of attributes:

  • x is the x-position of the player
  • y is the y-position of the player
  • quantity is the amount of food available

Food will be regenerated every X units of time.

Armor

Armor is an item that player can wear:

  • x is the x-position of the armor when player doesn't wear it.
  • y is the y-position of the armor when player doesn't wear it.
  • def is the RP defense value. See RP rules
  • weight is the weight of the armor.

Shield

Shield is an item that player can wear:

  • x is the x-position of the shield when player doesn't wear it.
  • y is the y-position of the shield when player doesn't wear it.
  • def is the RP defense value. See RP rules
  • weight is the weight of the shield.

Weapon

Weapon is an item that player can wear:

  • x is the x-position of the weapon when player doesn't wear it.
  • y is the y-position of the weapon when player doesn't wear it.
  • atk is the RP attack value. See RP rules
  • weight is the weight of the weapon.

Healing potion

Healing potion is an item that player can wear inside the backpack:

  • x is the x-position of the potion when player doesn't wear it.
  • y is the y-position of the potion when player doesn't wear it.
  • heal is the amount of HP the potion will heal.


Actions

The key on making Stendhal moving is to add actions. As we have seen each entity has a list of actions that can do. Let's see them and study they interact.

Player

Our main entity is Player, it is gamer's avatar in stendhal world and as such, it is able to do the next set of actions:

Move

Move action can be understand as two actions: Move to left,right,up or down while key is down
This action allows controlling gamer's avatar using our keyboard that is the arcade/adventure game style like Nintendo Zelda.

This action should have the next set of attributes:

  • dx horizontal speed of the avatar
  • dy vertical speed of the avatar

We can have as many as we want of this action. The last action executed will be the only one that alters really dx and dy.

Move to a position

This action allows controlling game's avatar using a mouse, so we can click ( or double click ) to move to the position where the mouse clicked. This mode is great for a more relaxed adventure game style like Bioware Baldur's Gate.

This action should have the next set of attributes:

  • x desired x coordinate of the avatar
  • y desired y coordinate of the avatar

We can only have ONE action of this type and only the latest one will be considered valid. This action is cancelled by any other action like Move, Attack, Face, ...

Both move actions will have at each end of turn, moving the avatar if it is possible dx units in the x axis and dy units in the y axis. If avatar collides with something while moving, dx and dy will become 0.

Face

This action is useful as a extra for the social side of the game; when you are talking it is often good to face the person you are talking too. So face action allows our character to look at the direction we tell it: left, right, up or down.

Chat

This action is the base of any social game like a MORPG.

This action should have the next set of attributes:

  • text text that the player is going to say

Due to Arianne framework it is not possible to create a yell or whisper action, when you talk, you talk for everybody in the area, that is why area design is *VERY* important to achieve a good gameplay.

Attack

This action is the core of the gameplay for lots of gamers to consider the game fun. All the combat is ruled by the RP game system explained in the RP section of this page.

There are some limitations for combat right now:

  • No PvP ( Player versus Player )
  • Can't attack yourself
  • Can't attack NPC

We want to preserve a nice game experience so we have removed player vs player combat. We can have only ONE attack action, so choose wisely your target, and this action is cancelled by any other action but Chat and Heal.

This action should have the next set of attributes:

  • target the object.ID of the player that we are attacking.

This action require that the target of the action is near our avatar. Near means that target's avatar have to be colliding with our avatar.

The attack action has the implicit meaning of following the target.

Equipment and Inventory

This action is very important as it handles most of the complexity and the fun of a RPG: getting new stuff and use items to solve quests.

TODO

RP

Role playing games are based in a set of rules. There are many set of rules: AD&D, GURPS, Warhammer,...
Stendhal defines a new typical set of rules, that has in common simplicity and ease of computing.

The system is based around 3 ideas:

  • Randomness using 1D6
  • Risk evaluation
  • Creativity

Risk evaluation gives the DM the power to weight up an action that a player wishes to perform against things like how experienced the player is in that type of action and the situation the player is in.

DM stands for Dungeon Master. In Stendhal our task is to design the DM, as it rules the game.

Attributes

Each player has a set of attributes that are:

  • attack - this value is used to resolve attack situations.
  • defense - this value is used to resolve situations where the player is attacked.
  • hp - this value stored the live points available.
  • level - this starts off as zero when the character is created and will increase related to experience
  • experience - this is the amount of experience gained at the current level

Entity Attribute values

The hardest part of any RP is to give balance to the values different entities has.

We need to give RP(atk, def and hp) values to:

Player

Let's make our starting player to be:

  • ATK - 2
  • DEF - 2
  • HP - 100

These values have been set randomly.

Sheep

A sheep can't attack, so it has to be weaker than player.

  • ATK - 0
  • DEF - 1
  • HP - 30

These values have alse been set randomly according to player values. Killing a sheep won't report you any experience.

Rat

A rat is the simplest enemy you can find in Stendhal, so it has to be simple enought for a Level 1 player to kill.

  • ATK - 3
  • DEF - 2
  • XP - 5
  • HP - 10

To set these values we have run a simulation until we have get the right look in the graphs.
http://arianne.sourceforge.net/wiki_images/rat.gif

Cave Rat

A cave rat is a stronger version of a rat, so it has to be simple enought for a Level 2-3 player to kill.

  • ATK - 6
  • DEF - 2
  • XP - 10
  • HP - 20

To set these values we have run a simulation until we have get the right look in the graphs.
http://arianne.sourceforge.net/wiki_images/caverat.gif

Wolf

A wolf is a common creature on plains and forest, it has to be simple enought for a Level 4-5 player to kill.

  • ATK - 6
  • DEF - 4
  • XP - 18
  • HP - 35

To set these values we have run a simulation until we have get the right look in the graphs.
http://arianne.sourceforge.net/wiki_images/wolf.gif

Experience and levels

All of the attributes can be increased during the game through gaining experience and levels. Experience is awarded by DM for several reasons:

  • good roleplaying
  • use of skills
  • combats

Experience can't be gained by training.

When you gain a level you can increase one of the attributes. To reach a level you need to reach the next experience points:

LevelExperience neededHP value
00100
1100110
2128120
3384130
4768140
51408150
62432160
73712170
85504180
97808190
1010624200

As you can deduce the HP grows at a rate of 10 per level, and ATK and DEF values are increased one on each new level. The formula to calculate XP is:

 exp = (10*level+5*level^2+10*level^3+80)

Combat

Combat is a fight between two or more players.

The combat is round based. Each round takes 5 turns.

The risk to strike a player can be written as:

  Attacker.attack VS Defender.defense/6 + 1D6

If player is hit we need to compute the wound that has been done:

  result = Attacker.attack/6 + 1D6 VS Defender.defense
  if result > 0:
    Defender.hp = Defender.hp - result
  end if

Death happens when hp reachs 0.

A critical hit happens when both die rolls are 6. And the damage is equal to Attacker.attack

Shields

The shield rating adds to your defense skill:

ShieldRating
Buckler shield+1
Small shield+2
Medium shield+3
Large shield+4
Tower shield+5
Green Scale shield+6
Black Scale shield+7
  • black/green scale shields are dropped from the black/green dragon.

Armour

Armour helps you absorb damage.

ArmourRating
Leather armour+1
Studded leather armour+2
Scale mail armour+3
Chain mail armour+4
Plate mail armour+5
Field plate armour+6
Full plate armour+7
Green Scaled armour+8
Black Scaled armour+9
  • black/green scaled armour are dropped from the black/green dragon.

Weapon

Weapon helps you to kill :)

WeaponRating
Knife+2
Club+3
Spear+4
Axe+5
Long sword+6
Two hand sword+7
Green Scaled sword+8
Black Scaled sword+9
  • black/green scaled swords are dropped from the black/green dragon.

Dead

The result of combat is usually dead.

When you kill a creature a corpse will appear. If you open it, you will be able to get whatever it has inside, usually food, gold, weapons, shields or armors.
Each time you kill a monster you are rewarded XP.

When you are killed you reappear on city and you lose your sheep if you have one.
Also to penalize dead, you are remove 10% of exp points and if it is the case you are removed HP, ATK and DEF increases because of level up.