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dragengine:modules:dragonscript:behaviortrees

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dragengine:modules:dragonscript:behaviortrees [2025/05/21 14:57] – dragonlorddragengine:modules:dragonscript:behaviortrees [2025/06/12 17:01] (current) – [File Format (*.debt)] dragonlord
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 The main use for this rule is to force waiting until a rule conditions fails. The main use for this rule is to force waiting until a rule conditions fails.
  
 +Since this rules returns ''BTResult.running'' it must have an ''id'' to make it persistable. A typical example is this:
 +<code xml>
 +<running id='.running'/>
 +</code>
 +
 +===== Yield =====
 +
 +Returns ''BTResult.running'' the first time the rule is run and ''BTResult.success'' otherwise.
 +
 +This rule causes the behavior tree to yield processing for one frame update to continue with the next rule the next time it is run. This rule prevents endless choice loops. Choice loops happen if all rules in a looping choice are not applying. The last rule has to be a rule returning ''BTResult.running'' to stop retesting all rules endlessly. After some time though this last rule has to return ''BTResult.success'' or the behavior tree is stuck forever in this rule. A typical solution is to use a short [[behavior_behaviortreetimer|ECBehaviorBehaviorTreeTimer]] to achieve this pause. This rule allows to yield processing for one frame in a simple way without needing to deal with timers.
 +
 +This rule can also be used to add single frame delays in a behavior tree, for example to ensure actors are not running actions too fast.
 +
 +Since this rules can return ''BTResult.running'' it must have an ''id'' to make it persistable. A typical example is this:
 +<code xml>
 +<yield id='.yield'/>
 +</code>
  
 ====== File Format (*.debt) ====== ====== File Format (*.debt) ======
  
-The behavior tree file format is recognized by the LoadBehaviorTree script class. The file is an XML file with a simple structure to define a behavior tree using XML.+The behavior tree file format is recognized by the LoadBehaviorTree script class. The file is an XML file with a simple structure to define a behavior tree using XML. See [[https://lordofdragons.github.io/dragengine/artifacts/xmlschema/dragengine/latest/behaviorTree.xsd|XML Schema]] for use with editors like VSCode.
  
 <uml> <uml>
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 } }
 behaviorTree --> yield behaviorTree --> yield
 +
 +object "subtree" as subtree {
 +  <#transparent,#transparent>|parameter|  <color:gray>string|
 +  |condition|  <color:gray>string|
 +  |conditionMode|  <color:gray>enum|
 +}
 +behaviorTree --> subtree
  
 @enduml @enduml
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 ^Attribute^Description^Occurance^Default^ ^Attribute^Description^Occurance^Default^
 |name|Name of action to run.|Required|-| |name|Name of action to run.|Required|-|
 +|id|Rule identifier. Required for actions potentially returning ''BTResult.running'' to support persistance. If identifier starts with ''.'' the parent rule identifier is prepended.|Optional|-|
 |doNotFail|If action fails return ''BTResult.success''. Useful to running optional actions without failing the parent rule.|Optional|''false''| |doNotFail|If action fails return ''BTResult.success''. Useful to running optional actions without failing the parent rule.|Optional|''false''|
  
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 ^Attribute^Description^Occurance^Default^ ^Attribute^Description^Occurance^Default^
 |loop|Loop sequence.|Optional|''false''| |loop|Loop sequence.|Optional|''false''|
 +|id|Rule identifier. Used to support persistance. If identifier starts with ''.'' the parent rule identifier is prepended.|Optional|-|
 |doNotFail|If sequence fails return ''BTResult.success''. Useful to optional sequences running as many rules in a sequence as possible without failing the parent rule.|Optional|''false''| |doNotFail|If sequence fails return ''BTResult.success''. Useful to optional sequences running as many rules in a sequence as possible without failing the parent rule.|Optional|''false''|
  
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 ^Attribute^Description^Occurance^Default^ ^Attribute^Description^Occurance^Default^
 |loop|Loop choice.|Optional|''false''| |loop|Loop choice.|Optional|''false''|
 +|id|Rule identifier. Used to support persistance. If identifier starts with ''.'' the parent rule identifier is prepended.|Optional|-|
 |doNotFail|If choice fails return ''BTResult.success''. Useful for optional choices there failing the choice should not fail the parent rule.|Optional|''false''| |doNotFail|If choice fails return ''BTResult.success''. Useful for optional choices there failing the choice should not fail the parent rule.|Optional|''false''|
  
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 Adds a running rule. Adds a running rule.
 +
 +^Attribute^Description^Occurance^Default^
 +|id|Rule identifier. Required to support persistance. If identifier starts with ''.'' the parent rule identifier is prepended.|Optional|-|
  
 ^Tag^Description^Occurance^Default^ ^Tag^Description^Occurance^Default^
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 ===== yield ===== ===== yield =====
  
-Adds a yield rule. This rule returns BTResult.running the first time it is run then it returns BTResult.true . This causes the behavior tree to yield processing for one frame update to continue with the next rule the next time it is run. This rule avoids endless choice loops in case all choice options are not applying. If no choice applies the behavior tree pauses and resumes with the next choice action during the next frame update. This rule avoids the need to use short timers to prevent choice loops as well as easily adding single frame delays if needed.+Adds a yield rule. 
 + 
 +^Attribute^Description^Occurance^Default^ 
 +|id|Rule identifier. Required to support persistance. If identifier starts with ''.'' the parent rule identifier is prepended.|Optional|-|
  
 ^Tag^Description^Occurance^Default^ ^Tag^Description^Occurance^Default^
dragengine/modules/dragonscript/behaviortrees.1747839460.txt.gz · Last modified: 2025/05/21 14:57 by dragonlord

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