LlScaleByFactor

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Summary

Function: integer llScaleByFactor( float scaling_factor );

Attempts to resize the entire object by scaling_factor, maintaining the size-position ratios of the prims.

Resizing is subject to prim scale limits and linkability limits. This function can not resize the object if the linkset is physical, a pathfinding character, in a keyframed motion, or if resizing would cause the parcel to overflow.
Returns a boolean (an integer) TRUE if it succeeds, FALSE if it fails.

• float scaling_factor The multiplier to be used with the prim sizes and their local positions.

Caveats

  • Due to floating point precision issues (often, sqrt(x*x) != x), avoid rescaling by the values returned by llGetMinScaleFactor and llGetMaxScaleFactor. To guarantee successful rescaling, use values slightly within the limits returned by those functions.
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Examples

//  Touching this script causes the object to double or halve in size.

integer growing;

default
{
    state_entry()
    {
        llSay(PUBLIC_CHANNEL, "Touch to toggle scale.");
    }

    touch_start(integer num_detected)
    {
        growing = !growing;

        float min_factor = llGetMinScaleFactor();
        float max_factor = llGetMaxScaleFactor();

        llSay(PUBLIC_CHANNEL, "min_scale_factor = " + (string)min_factor
                            + "\nmax_scale_factor = " + (string)max_factor);

        integer success;

        if (growing) success = llScaleByFactor(2.0);
        else         success = llScaleByFactor(0.5);

        if (!success) llSay(PUBLIC_CHANNEL, "Scaling failed!");
    }
}

See Also

Deep Notes

This function is roughly equivalent to the following:

float VectorAbsStatistics(integer flag, vector a){
    return llListStatistics(flag, [llFabs(a.x), llFabs(a.y), llFabs(a.z)]);
}

integer ScaleByFactor(float scale) {
    vector root = llGetScale() * scale;

    if (VectorAbsStatistics(LIST_STAT_MAX, root) > 64
        || VectorAbsStatistics(LIST_STAT_MIN, root) < 0.01
        || scale <= 0)
    {
        return ERR_MALFORMED_PARAMS;
    }

    integer prims = llGetNumberOfPrims();
    list set = [PRIM_LINK_TARGET, prims > 1, PRIM_SIZE, root];

    if (prims > 1) {
        list get = [];
        integer count = prims;
        do {
            get += [PRIM_LINK_TARGET, count, PRIM_SIZE, PRIM_POS_LOCAL];
        } while(--count);
        get = llGetPrimitiveParams(get);
        count = 0;
        do {
            vector size = llList2Vector(get, ++count) * scale;
            vector pos  = llList2Vector(get, ++count) * scale;

            if (VectorAbsStatistics(LIST_STAT_MAX, size) > 64
                || VectorAbsStatistics(LIST_STAT_MIN, size) < 0.01
                || VectorAbsStatistics(LIST_STAT_MAX, pos) > 54 )
            {
                return ERR_MALFORMED_PARAMS;
            }

            set += [PRIM_LINK_TARGET, prims,
                        PRIM_POS_LOCAL, pos,
                        PRIM_SIZE, size];
        } while(--prims > 1);
    }
    llSetPrimitiveParams(set);
    return TRUE;
}

History

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Signature

function integer llScaleByFactor( float scaling_factor );