I'm thinking of writing a small text-based adventure game, but I'm not particularly sure how I should design
the world from a technical standpoint.
My first thought is to do it
in XML, designed something like
the following. Apologies for
the huge pile of XML, but I felt it important to fully explain what I'm doing.
<level>
<start>
<!-- start
in kitchen with empty inventory -->
<room>Kitchen</room>
<inventory></inventory>
</start>
<rooms>
<room>
<name>Kitchen</name>
<description>A small
kitchen that looks like it hasn't been used
in a while. It has a table
in the middle, and there are some cupboards. There is a door to
the north, which leads to
the garden.</description>
<!-- IDs of
the objects
the room contains -->
<objects>
<object>Cupboards</object>
<object>Knife</object>
<object>Batteries</object>
</objects>
</room>
<room>
<name>Garden</name>
<description>The garden is wild and full of prickly bushes. To
the north there is a path, which leads into
the trees. To
the south there is a house.</description>
<objects>
</objects>
</room>
<room>
<name>Woods</name>
<description>The woods are quite dark, with little light bleeding
in from
the garden. It is eerily quiet.</description>
<objects>
<object>Trees01</object>
</objects>
</room>
</rooms>
<doors>
<!--
a door isn't necessarily a door.
each door has a type, i.e. "There is a <type> leading to..."
from and to are references
the rooms that this door joins.
direction specifies
the direction (N,S,E,W,Up,Down) from <from> to <to>
-->
<door>
<type>door</type>
<direction>N</direction>
<from>Kitchen</from>
<to>Garden</to>
</door>
<door>
<type>path</type>
<direction>N</direction>
<from>Garden</type>
<to>Woods</type>
</door>
</doors>
<variables>
<!-- variables set by actions -->
<variable name="cupboard_open">0</variable>
</variables>
<objects>
<!-- definitions for objects -->
<object>
<name>Trees01</name>
<displayName>Trees</displayName>
<actions>
<!-- any actions not defined will show
the default failure message -->
<action>
<command>EXAMINE</command>
<message>The trees are tall and thick. There aren't any low branches, so it'd be difficult to climb them.</message>
</action>
</actions>
</object>
<object>
<name>Cupboards</name>
<displayName>Cupboards</displayName>
<actions>
<action>
<!-- requirements make
the command only work when they are met -->
<requirements>
<!-- equivilent of "if(cupboard_open == 1)" -->
<require operation="equal" value="1">cupboard_open</require>
</requirements>
<command>EXAMINE</command>
<!-- fail message is
the message displayed when
the requirements aren't met -->
<failMessage>The cupboard is closed.</failMessage>
<message>The cupboard contains some batteires.</message>
</action>
<action>
<requirements>
<require operation="equal" value="0">cupboard_open</require>
</requirements>
<command>OPEN</command>
<failMessage>The cupboard is already open.</failMessage>
<message>You open
the cupboard. It contains some batteries.</message>
<!-- assigns is a list of operations performed on variables when
the action succeeds -->
<assigns>
<assign operation="set" value="1">cupboard_open</assign>
</assigns>
</action>
<action>
<requirements>
<require operation="equal" value="1">cupboard_open</require>
</requirements>
<command>CLOSE</command>
<failMessage>The cupboard is already closed.</failMessage>
<message>You closed
the cupboard./message>
<assigns>
<assign operation="set" value="0">cupboard_open</assign>
</assigns>
</action>
</actions>
</object>
<object>
<name>Batteries</name>
<displayName>Batteries</displayName>
<!-- by setting inventory to non-zero, we can put it
in our bag -->
<inventory>1</inventory>
<actions>
<action>
<requirements>
<require operation="equal" value="1">cupboard_open</require>
</requirements>
<command>GET</command>
<!-- failMessage isn't required here, it'll just show
the usual "You can't see any <blank>." message -->
<message>You picked up
the batteries.</message>
</action>
</actions>
</object>
</objects>
</level>
Obviously there'd need to be more to it than this. Interaction with people and enemies as well as death and completion are necessary additions. Since
the XML is quite difficult to work with, I'd probably create some sort of world editor.
I'd like to know if this method has any downfalls, and if there's a "better" or more standard way of doing it.
