Difference between revisions of "HPL3/Scripting/Scripting Guide/Sequences"

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== Introduction ==
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Many of the events that happen inside map script files are triggered sequences. For example: A sound plays, then the player's FoV changes, then a light starts flashing, etc.
 
Many of the events that happen inside map script files are triggered sequences. For example: A sound plays, then the player's FoV changes, then a light starts flashing, etc.
  
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     SequenceStates_Resume("Sequence_Alert");
 
     SequenceStates_Resume("Sequence_Alert");
 
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</syntaxhighlight>As you can see, <code>Sequence_DoStepAndPause()</code> in there actually pauses the whole sequence until some external event - in this case the callback from the voice playing code - calls <code>SequenceStates_Resume()</code> and asks it to continue.
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As you can see, <code>Sequence_DoStepAndPause()</code> in there actually pauses the whole sequence until some external event - in this case the callback from the voice playing code - calls <code>SequenceStates_Resume()</code> and asks it to continue.
  
 
To start the sequence, you just call the sequence function once with an empty argument when you want it to trigger:<syntaxhighlight lang="c++">
 
To start the sequence, you just call the sequence function once with an empty argument when you want it to trigger:<syntaxhighlight lang="c++">

Latest revision as of 12:23, 14 August 2020

  1. The Basics - Introduction
  2. What is scripting in HPL3?
  3. Setting up CodeLite - Scripting Tool
  4. Scripting Workflow and Structure
  5. Hello World
  6. Calling Functions and Function Callbacks
  7. Helper Files
  8. The OnAction method
  9. The Update method
  10. Timers
  11. Sequences
  12. Local and Global Variables
  13. Enums
  14. Conclusion

Many of the events that happen inside map script files are triggered sequences. For example: A sound plays, then the player's FoV changes, then a light starts flashing, etc.

We control all of those through a set of wrappers we call Sequences, which hide a bunch of timers away and make things easier to read.

They are very useful when we need to handle a big amount of timers that should occur one after another - or in other words - a sequence.

Workflow

For each sequence you need a map property to store the state - a cSequenceStatesData property: 

cSequenceStatesData mSequenceAlert;
Then you create a sequence function. This will be repeatedly called until the whole sequence is over. It looks something like this:
cSequenceStatesData mSequenceAlert;
void Sequence_Alert(const tString& in asName)
{
    Sequence_Begin("Sequence_Alert", mSequenceAlert);
    
    if(Sequence_DoStepAndWait(1.0f))  // Do this step and then wait for 1 second
    {
        MakeALoudNoise();
    }
    else if (Sequence_DoStepAndWait(2.5f)) // Do this and then wait for 2.5 seconds
    {
        FlashABrightLight();
    }
    else if (Sequence_DoStepAndPause()) // Do this and then pause until told otherwise
    {
        SaySomethingAndCallBack("OnSayingSomethingComplete");
    }
    else if (Sequence_DoStepAndWait(10.0f)) // Do this and then wait for 10s
    {
        CrushPlayerLikeAnAnt();
    }
    else if (Sequence_DoStepAndContinue()) // Do this and go on to the next step (in this case there isn't one)
    {
        ApologiseToPlayer();
    }
    
    Sequence_End();
}

void OnSayingSomethingComplete()
{
    // Saying something is now complete - poke the sequence to continue processing
    SequenceStates_Resume("Sequence_Alert");
}

As you can see, Sequence_DoStepAndPause() in there actually pauses the whole sequence until some external event - in this case the callback from the voice playing code - calls SequenceStates_Resume() and asks it to continue.

To start the sequence, you just call the sequence function once with an empty argument when you want it to trigger:

Sequence_Alert("");

No need to call it every frame or anything! Once started, timers will automatically make sure that the sequence steps get followed when they need to be.

Icon tip.png Tip: Since sequences are totally independent of each other, you could run multiple sequences in parallel.

See Also

← Timers
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