Getting Your Current Global Coordinates in LSL (Linden Scripting Language)
This guide explains how to retrieve your avatar's global coordinates within a Linden Scripting Language (LSL) script for Second Life. We'll cover the core function, potential issues, and ways to handle them.
The Core Function: llGetPos()
The simplest way to get your avatar's global coordinates is using the built-in LSL function llGetPos(). This function returns a vector containing the X, Y, and Z coordinates of the object (in this case, your avatar) it's called on.
default
{
state_entry()
{
vector3 myPos = llGetPos();
llSay(0, "My current coordinates are: " + (string)myPos);
}
}
This script retrieves the coordinates and prints them to your local chat. The output will be in the format X Y Z, representing the global coordinates.
Understanding the Coordinate System
Second Life uses a three-dimensional Cartesian coordinate system.
- X-axis: Generally runs East-West. Positive values are East, negative values are West.
- Y-axis: Generally runs North-South. Positive values are North, negative values are South.
- Z-axis: Represents altitude. Positive values are above the sim's ground level, negative values are below.
Potential Issues and Solutions
While llGetPos() is straightforward, you might encounter situations where the returned coordinates aren't entirely accurate or behave as expected:
1. Teleportation and Region Crossing:
When teleporting or crossing region boundaries, there might be a slight delay before llGetPos() reflects the updated coordinates. To mitigate this, you could implement a short timer or check for coordinate changes over time.
default
{
vector3 lastPos;
state_entry()
{
lastPos = llGetPos();
llSetTimerEvent(0.1); // Check every 0.1 seconds
}
timer()
{
vector3 currentPos = llGetPos();
if (llVecDist(currentPos, lastPos) > 0.1) // Significant change detected
{
llSay(0, "Coordinates updated: " + (string)currentPos);
lastPos = currentPos;
}
}
}
This improved script checks for significant coordinate changes before updating the displayed position.
2. Object's Position vs. Avatar's Position:
Remember that llGetPos() gets the object's position, not necessarily the avatar's precise location within the object (if you attach the script to an object). If attached to something on your avatar, the coordinates will reflect that object's position, not your exact center.
To get the avatar's precise location, attach the script directly to your avatar.
3. Accuracy Limitations:
The accuracy of llGetPos() is limited by the Second Life simulator's precision. Don't expect perfect, down-to-the-millimeter accuracy.
4. Region-Specific Coordinates:
Coordinates are global, but the simulator uses different regions. You will get the same global coordinates even if your avatar is in different sims.
Further Considerations
For more advanced applications, you might want to combine llGetPos() with other functions:
llGetRegionName(): Get the name of the current region.llGetAgentInfo(): Retrieves various information about an avatar, including its position, although it's less direct thanllGetPos().
By understanding these points and utilizing the provided examples, you can effectively retrieve and utilize your avatar's global coordinates within your LSL scripts. Remember always to test your scripts thoroughly to ensure they function as expected under various conditions.
