User:Dora Gustafson/sundirection and time of day

From Second Life Wiki
Jump to: navigation, search

Show Sun Direction and compare to Time of Day

Conclusion when compared to the Windlight default day cycle:

  • When the SunDirection vector is confined to the X-Z plane(Ecliptic) the result matches fairly well what is seen.
  • The moon direction is not always opposite the sun direction.
  • When the east point in Windlight is moved the SunDirection vector doesn't move with it.
  • The often used method of using the Z component to separate day from night is very rough. Sunset and sunrise are both (equivalent)hours from where the sign of Z changes.
// sun pointer script by Dora Gustafson, Studio Dora 2012
// Will point the prim's FWD in the SunDirection
// Will show the SunDirection vector and the equivalent real day hour
// vertical ecliptic matches the default day cycle sun in windlight
 
float sd_Rate=10.0;
integer vertical=TRUE; // vertical ecliptic
 
rotation Vec2Rot( vector FWD )
{
    FWD = llVecNorm( FWD );
    vector UP = < 0.0, 1.0, 0.0 >;
    vector LEFT = llVecNorm(UP%FWD);
    if (vertical) FWD = llVecNorm(LEFT%UP);
    else UP = llVecNorm(FWD%LEFT);
    return llAxes2Rot(FWD, LEFT, UP);
}
 
default
{
    state_entry()
    {
        llSetTimerEvent(sd_Rate);
    }
    timer()
    {
        llSetRot( Vec2Rot( llGetSunDirection()));
        float secs = 6.0*llGetTimeOfDay(); // multiply by 6 to show the equivalent real day hour
        integer minutes = ((integer)secs/60)%60;
        integer hours = (integer)secs/3600;
        llSetText("Sundirection: "+(string)llGetSunDirection()+"\nSim Time: "+(string)hours+"H "+(string)minutes+"M", <1.0,1.0,1.0>, 1.0);
    }
}