Difference between revisions of "Touch start"

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m (Replaced old <LSL> block with <source lang="lsl2">)
(Added caveat about multi-prim objects with multiple touch_start() handlers. Cleaned up a bit of formatting.)
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|p1_type=integer
 
|p1_type=integer
 
|p1_name=num_detected
 
|p1_name=num_detected
|p1_desc=Number of agents detected touching during the last clockcycle
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|p1_desc=Number of agents detected touching during the last clock cycle
 
|event_desc=Triggered by the start of agent clicking on task
 
|event_desc=Triggered by the start of agent clicking on task
 
|constants
 
|constants
 
|spec
 
|spec
 
|caveats=* If a prim [[face]] has [[Navigating Shared Media|Shared Media]] enabled and the avatar's viewer supports this feature, LSL scripts will not detect touches on that face. Touches from older clients will be detected.
 
|caveats=* If a prim [[face]] has [[Navigating Shared Media|Shared Media]] enabled and the avatar's viewer supports this feature, LSL scripts will not detect touches on that face. Touches from older clients will be detected.
|examples=You can use numbers 0 through (num_detected-1) with the various llDetected... functions to get detected agent keys etc. For most purposes, it is adequate to bother only with the first detected toucher e.g. llDetectedKey(0). It is rare (but not impossible) for num_detected to be other than 1.
+
* If you have a multi-prim object and the root has a [[touch_start]] handler AND one or more child prims has a [[touch_start]] handler, the root prim's handler will be called when it (the root) or a child without a handler is touched. If you touch a child prim that has a [[touch_start]] handler, it will receive the event and the root prim will not.
 +
|examples=You can use numbers 0 through (<code>num_detected</code>-1) with the various <code>llDetected</code>... functions to get detected agent keys etc. For most purposes, it is adequate to bother only with the first detected toucher e.g. [[llDetectedKey]](0). It is rare (but not impossible) for <code>num_detected</code> to be other than 1.
 
<source lang="lsl2">
 
<source lang="lsl2">
 
default
 
default
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|also_articles
 
|also_articles
 
|also_footer
 
|also_footer
|notes=*If using a touch to change states be careful about the touch_ event order. '''The best advice is NOT to do state changes from within touch_start.''' Add a touch_end event and do the state change there. Changing state from within touch_start can cause the next occurrence of THIS touch_start code to be missed.   
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|notes=*If using a touch to change states be careful about the touch event order. '''The best advice is not to do state changes from within touch_start.''' Add a [[touch_end]] handler and do the state change there. Changing state from within [[touch_start]] can cause the next occurrence of THIS [[touch_start]] code to be missed.   
  
*On clicking a prim with touch events we trigger touch_start (on first contact), touch (during) and touch_end (as released).  
+
*On clicking a prim with touch event handlers, the following handlers are triggered: [[touch_start]] (on first contact), [[touch]] (during) and [[touch_end]] (as released).  
 
|mode
 
|mode
 
|deprecated
 
|deprecated

Revision as of 10:23, 1 January 2016

Description

Event: touch_start( integer num_detected ){ ; }

Triggered by the start of agent clicking on task

• integer num_detected Number of agents detected touching during the last clock cycle

Caveats

  • If a prim face has Shared Media enabled and the avatar's viewer supports this feature, LSL scripts will not detect touches on that face. Touches from older clients will be detected.
  • If you have a multi-prim object and the root has a touch_start handler AND one or more child prims has a touch_start handler, the root prim's handler will be called when it (the root) or a child without a handler is touched. If you touch a child prim that has a touch_start handler, it will receive the event and the root prim will not.
All Issues ~ Search JIRA for related Bugs

Examples

You can use numbers 0 through (num_detected-1) with the various llDetected... functions to get detected agent keys etc. For most purposes, it is adequate to bother only with the first detected toucher e.g. llDetectedKey(0). It is rare (but not impossible) for num_detected to be other than 1.

default
{ 
    touch_start(integer num_detected)
    {
        key    avatarKey  = llDetectedKey(0);
        string avatarName = llDetectedName(0);
 
        llInstantMessage(avatarKey, "Hello " + avatarName );
    }
}

Notes

  • If using a touch to change states be careful about the touch event order. The best advice is not to do state changes from within touch_start. Add a touch_end handler and do the state change there. Changing state from within touch_start can cause the next occurrence of THIS touch_start code to be missed.
  • On clicking a prim with touch event handlers, the following handlers are triggered: touch_start (on first contact), touch (during) and touch_end (as released).

Deep Notes

Signature

event void touch_start( integer num_detected );