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SKILLS/EXPERIENCE DOCUMENTATION for DEVELOPERS |
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---------------------------------------------- |
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|
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- Summary - |
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0. Introduction |
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1. Sketch of system |
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a. Initialization - how skills and experience are linked |
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|
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2. How to add new skills |
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a. creation of new skill: outline of needed steps |
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3. Detail of skill archetype values. |
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4. Skill Tools |
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5. Skill Scrolls |
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6. Other Objects |
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7. Workings of the Skill System |
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8. Changes & Limitations |
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------------------------------------------------------------------------- |
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0. Introduction |
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--------------- |
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|
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Skills were redone to a large extent in April 2003. This document has been |
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updated to reflect how the skills work. |
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The main change is that experience categories were removed from the game. |
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Instead, experience goes to the skill itself. Thus. how good a player is at |
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the skills is directly proportional to how good they are at that skill, and |
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not the category itself. |
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|
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1. Sketch of system |
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------------------- |
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|
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In the skills/experience code, players gain experience for the activities |
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which they perform in the game ("You are what you do"). The activities a |
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player may engage in are controlled by the skills they possess. All players |
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start with a basic set of skills which they may expand through adventuring. |
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While monsters do not gain experience from the use of skills, they may use any |
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skills which exist in their inventory if they have the can_use_skill flag set. |
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|
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In the code, skills are objects which exist in the player/monster inventory. |
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Both NPC/monsters and players use the same skill archetypes. Not all skills |
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are however enabled for monster use. Check the Skills_players.doc for |
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available NPC skills. |
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|
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The experience one gets for a skill is greatly simplified. No longer |
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is it weighted based on the stats of the player. Rather, the experience is |
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based on what the skill was used for - opening a tough trap gets more |
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exp than opening an easy trap. The stats the player has will improve |
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the chances of success in most cases - this is bonus enough without also |
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gaining additional experience. |
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|
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The chracters total experience is no longer related to the sum of experience |
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in the players skills - A player could for example only of 1000 exp, but have |
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skills with 2500 exp, 300 exp, etc. Removing the tie between skills and total |
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experience allows for reasonable skill advancement - you can allow a player |
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to easily get to level 20 in a skill without them now being level 20 player. |
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|
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Note also that the only tunables are now in the code or in the archetypes - |
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if the exp for disarming is out of whack, the code would need to be changed |
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to give more appropriate amounts. |
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|
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2. How to add new skills |
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------------------------- |
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|
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Adding a new skill to CF is not overly difficult, it is little more difficult |
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than adding new archetypes and a spell to the game. |
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a. creation of new skill: outline of needed steps |
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A number of steps are required to create a new skill. |
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1) Edit a new skills archetype. See below for appropriate parameters. If |
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you desire the skill to be a skill tool, edit a "face" for the new skill. |
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If you want to have the skill to be learned via a skill scroll, edit a |
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skillscroll for the skill. Place the new archetype(s) in the |
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lib/arch/skills directory. Remember to name your new skill appropriately |
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(ie skill_<new skill name>). Make sure you select a unique subtype |
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for your new skill. |
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|
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2) Edit skill_util.c. Add an entry for the skill in do_skill() (so that it may |
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be used as a "long-range attack"). If the new skill is a hth attack take a |
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look at the attack_hth_skills[] table in do_skill_attack() -- where does |
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the hth attack rank? The most useful attacks should occur earlier in the |
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table. |
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|
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3) Create the skill code. If you created a hth attack, you probably can get |
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away with just using attack_hth. For other skills, put the skill code in |
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skills.c. If your new skill is to be an "associated" skill, then make sure |
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that it returns the value of calc_skill_exp(). |
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4) Edit treasures/artifacts file as needed (esp. if your skill will become one |
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of the starting skills, or will show up in shops.) |
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3. Detail of skill archetype values. |
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------------------------------------ |
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This section details the various object/archetype values. |
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First, we detail skill objects: |
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type: SKILL (43) |
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subtype: subtype of skill |
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invisible: 1 |
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no_drop: 1 |
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name: Name of the skill, used by things like 'use_skill', as well as output |
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of 'skills' command. |
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skill: Same as name - this simplifies code, so that we can look at |
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op->skill for both skills and skill tools. It also means that if a skill |
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named is passed, we can verify we have the matching entry. |
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stats (Str, Dex, sp, grace, etc): These modify the abilities of the player, |
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in a sense giving bonuses. |
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expmul: this is the ratio of experience the players total should increase by |
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when this skill is use. If this is zero, then experience only goes to |
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to the skill. Values higher than 1 are allowed. Note that experience |
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rewarded to the players total is in addition to that given to the |
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skill. Eg, if player should get 500 exp for using a skill, and |
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expmul is 1, the player will get 500 added to that skill as well as |
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500 to their total. |
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|
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exp: The exp the player has in the skill (object). If this is an archetype, |
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this contains the base amount the player gets for using the skill. |
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exp will be set to 0 when the skill is given to the player. |
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level: Object: The level of this skill - this is just determined from the exp |
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above based on the experience table. Archetype: This is a percentage value |
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that determines how the level difference effects experience rewards (like |
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the old lexp value). Basically, if it is set to 100, the ratio is normal |
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(eg, if opponent is twice level of player, player would get twice as much |
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normal exp). If level is 200, player would get 4 times. If level if 50, |
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player would half normal. If level is 0, then we don't adjust exp reward |
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based on level. |
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can_use_skill (flag): If this is set, the player knows the skill natively |
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(eg, does not need a skill tool, see below). If this is not set, |
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then this skill object is acting as a container for experience. |
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For example, if a player is using a holy symbol in order to get his |
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praying skill, we still need to have skill_praying in the players |
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inventory to store the experience in. However, the player can't |
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use that praying skill without a holy symbole until they learn it from a |
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skill scroll. |
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4. Skill Tools |
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----------------- |
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Skill tools are items that let a player use a skill they do not otherwise |
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know. Skill tools may also have advantages, eg, spellpaths they grant to the |
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caster, stat bonuses, etc. |
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Most of the values for the skill tools are just like normal equipment |
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(value, weight, face, body_..., ) fields. |
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type: skill_tool (74) |
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skill: Name of the skill this object allows the user of. |
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Note - the old skill code used 'sp' to denote the skill to use. |
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5. Skill Scrolls |
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---------------- |
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type: SKILLSCROLL |
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skill: Name of the skill to be learned |
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Rest of the values are per normal equipment (weight, value, identified, |
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etc). |
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6. Other Objects |
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---------------- |
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Many other objects will use the 'skill' field in their object to denote |
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what skill is needed to use this object. Thus, for examples, readable |
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objects have 'skill literacy' to denote that the literacy skill is |
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needed to read them. Weapons have 'skill' values to denote what |
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skill is needed to use the weapon. Same for spells. |
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------------------------------- |
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7. Workings of the Skill System |
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------------------------------- |
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This section attempts to briefly explain how this all works. |
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Due to the addition of the skill pointer, it is no longer required |
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that a skill be in the ready_skill position to gain experience. |
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Whenever a player tries to use skill either directly (ready_skill ..) |
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or indirectly (cast a spell which requires knowledge of the skill), the |
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code will examine the players inventory to see if they an in fact |
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use the skill. This first checks to see if the player has the appropriate |
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skill archetype in their object. If they do, and can_use_skill is set |
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to 1, nothing more is done. If that is not the case, we then look for |
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a skill tool. If none is found, we tell the player the can't use the |
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skill. If one is found, we try to apply the skill tool - if this can not |
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be done, we also error out. |
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Only if the player explicitly activates a skill with ready_skill do |
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we change the players range pointer. Otherwise, it will remain as is |
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(but not that casting a spell might also change the range pointer). |
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add_exp has been modified to take two additional parameters - |
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skill_name and flag. |
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skill_name is the skill to add the experience to. By passing this |
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to add exp, a lot of the code no longer needs to change chosen_skill, |
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then reset it back again. |
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flag determines what to do if the player does not currently have the |
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skill pointer in their inventory. This can arise if the player |
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is using a skill tool, or part of a party. |
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In the default case of flag being 0, if the player does not currently |
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have the skill in their inventory, this is added (with can_use_skill 0). |
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If flag is 1, we add the exp to the players total exp, but don't |
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give them any in the skill. If it is 2, the player gets nothing. |
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This fixes many of the abuses of party combat - if a member of your |
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party is killing things with wizardry, you'll get wizardry exp. If |
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you don't have wizardry, you'll get some general exp, but you can't |
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funnel it into things like alchemy anymore. |
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The effect of flag 1 to add exp is so that that a player can't have |
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thousands of exp in a skill and never have used in themselves - for a player |
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to have any exp in a skill, he will have had to use it at least once. Note |
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however that a player could have used the skill just once (to say kill a |
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kobold) and yet get a bunch more exp from party members that are actually good |
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wizards. |
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The handling of add_exp with skill_name is pretty simple. In most cases, we |
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know immediately the skill that was used (eg, melee combat, search, disarm, |
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etc). In cases of indirect death (spells), we set the skill in the spell |
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object to the skill that it should get awarded to. |
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|
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------------------------ |
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8. Changes & Limitations |
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------------------------ |
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|
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The old skill system had the idea of stats that effect the skill. There |
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is no good way to do that within the new system - instead, the code |
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the executes the skill will do this. This really isn't much worse |
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than the old system anyways - the old code still did things like |
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'stat average * 3' or otherwise determine how important the stats are. |
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|
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In addition, this allows for more flexibility for multi faceted |
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skills. For example, the identification portion of some skills should |
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probably use int, but the creation portion should perhaps be dex and strength. |
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|
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There is no more SK_level function - while this could still be useful |
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to replace code like |
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|
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level= op->chosen_skill?op->chosen_skill->level:op->level; |
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|
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the use of automatically de-referencing the op->chosen_skill is not |
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suggested - the new skill system is much more lenient on passing the |
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appropriate skill object to functions that need it, so calls to |
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SK_level in most cases may not really be the right approach - in many |
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cases, the chosen_skill may not be what the code is really expecting. |
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