Storytron uses a different approach from the ones introduced before but shares some similarities with IDtension in the sense of using sentences with placeholders for creating the story. Basically the user creates her/his input by selecting different options (a single word or a group of words) and creating a more complex sentence in the end which is then processed by the system. Each actor is able to react to this depending on certain rules authors have to create beforehand. Criterions for the decisions of the actor are for example the choosing of a role, a reaction depending on that role and the filling-in of words and groups of words into the sentence which has a predefined structure and placeholders at certain points. These placeholders are variables for all content present in the story world and have different types (e.g. actors, places, items…).
Each decision of the system depends on conditions. So have authors to write conditions which role has to be chosen, which reactions is performed and which values are used for the variables that make up a sentence structure. The figure below shows a simple generic sentence for the action “drink” and the drop down buttons indicate that the subject, a quantifier and a prop can be chosen from a list.
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For each of these variables a condition has to be written that determines which values of the list are allowed to be entered in the current situation and then which of these values is the preferred one. The next figure shows a complex equation that computes such a preference value. Storytron uses an own language for these computations that is visualised in a tree-like view. The condition itself is quite simple and only implicitly present in the interface, because always the option with the highest previously computed value is chosen. However, as you can see below the complexity of the equation can be high, depending on the wanted result, because Storytron offers a wide range of operators.
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Basically the conditions found in Storytron have the following structure (in the IF-THEN-ELSE sense) for three choices (more or less are possible):
IF ( ( Option_A_preference_value > Option_B_preference_value )
AND ( Option_A_preference_value > Option_C_preference_value ) ) THEN
ACTION:
Choose_Option_A
ELSE
IF ( ( Option_B_preference_value > Option_A_preference_value )
AND ( Option_B_preference_value > Option_C_preference_value ) ) THEN
ACTION:
Choose_Option_B
ELSE
IF ( ( Option_C_preference_value > Option_A_preference_value )
AND ( Option_C_preference_value > Option_B_preference_value ) ) THEN
ACTION:
Choose_Option_C
Keep in mind that these conditions are only implicitly present and the focus of Storytron is writing the computation equations of the preference values.
Effects are defined in a similar way to the other tools. A variable is chosen that should be changed by the chosen action and then a value is assigned or a more complex computation process begins. The example below shows the setting of the variable Weak_Strong to the value 0.5.
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