determining location of a "touch" ?

I was just curious if it is possible to determine where an object was "touched" when a person clicks it? I was thinking for example of a 8x8 checkerboard type thing where you would be able to click on the board and have the board respond based on which square you touched. The obvious solution is to have individual squares be prims but then you are talking about 64 prims vs 1 prim with a checkerboard texture and I was wondering if there was a way of doing this.

Use the llDetectedTouch functions. See the SL wiki at http://wiki.secondlife.com/wiki/LlDetectedTouchST.

lol, n/m someone beat me to it

hmm, this example:

//Sets a grid of x by y, in this case 144 squares and returns that number on touch.
 
float x=12.0;
float y=12.0;
integer Pos;
 
default{
 
    touch_start(integer total_number){
        if (llDetectedTouchFace(0) == -1)
            llOwnerSay("old client");
        else{
            vector pos = llDetectedTouchST(0);
            Pos = ((llFloor((pos.x*10)*x)/10)*(integer)y)+llCeil(pos.y*y);
            llOwnerSay((string)Pos);
        }
    }
}

seems to be reversed for how you would look at the x and y of a texture, i can't seem to figure out how to make it the same within the script without rotating the prim and/or texture

ooh very good... i missed the llDetectedTouch stuff when I was looking... I really thought the answer was going to be that you can't do it. I'm glad I asked. Thanks!

In your defense, it is a pretty new feature. =)

Which does raise the point that you should be aware that it doesn't work for people using older viewers. It would be nice to know how many people still haven't upgraded...

using the crosshair example from that page looks cool. i'm trying to apply that to llRezObject, can't seem to figure out the math i need to apply to make it rez the object at the touched point

nevermind, i needed llDetectedTouchPos, but i was trying to use llDetectedTouchST so that i could make the rezzed object centered on the square, llDetectedTouchPos rezzes exactly where you touch it

..yes, and it STILL needs update in wiki
as do
http://www.lslwiki.net/lslwiki/wakka.php?wakka=functions:
llDetectedTouchBinormal (1.21)
llDetectedTouchFace (1.21)
llDetectedTouchNormal (1.21)
llDetectedTouchST (1.21)
llDetectedTouchUV (1.21)

-someone with wiki editing rights (and insight) is needed to udtate the wiki..!

BR

It's a wiki, everyone has editing rights

so from reading the SL Wiki on detectedtouchuv. it returns the uv of the texture? no matter how it's rotated or repeated, say i have a dot in the top right corner, anytime i touch it, it will always return the same uv?

UV returns it relative to the Texture, ie repeats and such WILL affect the result. ST is relative to the Face of the prim. Pos is relative to the Region.

If I recall from the brief testing I did of llDetectedTouchUV(), it returns values in the range (0,0)..(1,1) only for ONE of the repeats of the texture. However, it's a pretty simple matter to do a floating point style modulo operation to get the position on the texture for any other repeat. Something like:

vector normalizeUVCoords(vector uvCoords)
{
   uvCoords.x = uvCoords.x-llFloor(uvCoords.x);
   uvCoords.y = uvCoords.y-llFloor(uvCoords.y);
   return uvCoords;
}