Z&A Light Ribbon.lsl

//////////////////////////////////////////////////////////////////////
// Z&A Light Ribbon
// By Antony Fairport
//
// Z&A Light Ribbon - Quick and simple glowstick/ribbon
//
// Revision history:
// ------------------------------------------------------------
//
// 2016-06-25
// Initial revision.

//////////////////////////////////////////////////////////////////////
// Make the ribbon
MakeRibbon( vector vStartColour, vector vEndColour )
{
    // Get the size of the stick, so we can adjust the particle.
    vector vStickSize = llGetScale();

    llParticleSystem( [
        PSYS_PART_FLAGS,       PSYS_PART_RIBBON_MASK       |
                               PSYS_PART_INTERP_COLOR_MASK |
                               PSYS_PART_EMISSIVE_MASK,
        PSYS_PART_MAX_AGE,     0.75,
        PSYS_SRC_TEXTURE,      TEXTURE_BLANK,
        PSYS_PART_START_SCALE, < vStickSize.z, 0.02, 0.0 >,
        PSYS_PART_START_ALPHA, 0.5,
        PSYS_PART_END_ALPHA,   0.0,
        PSYS_PART_START_GLOW,  0.2,
        PSYS_PART_END_GLOW,    0.05,
        PSYS_PART_START_COLOR, vStartColour,
        PSYS_PART_END_COLOR,   vEndColour
    ] );
}

//////////////////////////////////////////////////////////////////////
// Refresh the ribbon, loading colours from object desc.
RefreshRibbon()
{
    // Get the description as a list.
    list lColours = llParseString2List( llGetObjectDesc(), [ "~" ], [] );

    // The start and end colours.
    vector vStart = <  1.0, 0.0, 0.0 >;
    vector vEnd   = < 0.01, 0.0, 0.0 >;

    // If we seem to have got enough stuff from the description...
    if ( llGetListLength( lColours ) > 1 )
    {
        // ...assume we're getting colours.
        vStart = (vector) llList2String( lColours, 0 );
        vEnd   = (vector) llList2String( lColours, 1 );
    }

    // Texture the stick itself.
    llSetLinkPrimitiveParamsFast( LINK_THIS, [
        PRIM_GLOW,       ALL_SIDES, 0.2,
        PRIM_FULLBRIGHT, ALL_SIDES, TRUE,
        PRIM_COLOR,      ALL_SIDES, vStart, 1.0
    ] );

    // Make the ribbon.
    MakeRibbon( vStart, vEnd );
}

//////////////////////////////////////////////////////////////////////
// Default state.
default
{
    //////////////////////////////////////////////////////////////////
    // State entry.
    state_entry()
    {
        // Restrict memory. We don't need much.
        llSetMemoryLimit( 12 * 1024 );

        // Get the ribbon off.
        RefreshRibbon();
    }

    //////////////////////////////////////////////////////////////////
    // When rezzed...
    on_rez( integer _ )
    {
        RefreshRibbon();
    }

    //////////////////////////////////////////////////////////////////
    // Handle being atached.
    attach( key id )
    {
        if ( id )
        {
            RefreshRibbon();
        }
    }

    //////////////////////////////////////////////////////////////////
    // Handle changes.
    changed( integer change )
    {
        // If the owner has changed...
        if ( change & CHANGED_OWNER )
        {
            // ...reset the script.
            llResetScript();
        }
        // If the size of the stick changed...
        else if ( change & CHANGED_SCALE )
        {
            // ...refresh the particles.
            RefreshRibbon();
        }
    }
}