# Difference between revisions of "User:Dora Gustafson/llAxes2Rot right and wrong"

From Second Life Wiki

Line 93: | Line 93: | ||

* Red: "Bastard" routine, Not unit and not orthogonal. | * Red: "Bastard" routine, Not unit and not orthogonal. | ||

* Yellow: "Norm" routine, unit vectors but not orthogonal. | * Yellow: "Norm" routine, unit vectors but not orthogonal. | ||

− | * Green: "True" routine, true direction. | + | * Green: "True" routine, true direction, the demands are met. |

− | * Blue: "Hor" routine, direction in the horizontal plane only. | + | * Blue: "Hor" routine, direction in the horizontal plane only, the demands are met. |

## Revision as of 07:17, 5 August 2009

To see if it really matters this demands on unit vectors and orthogonality, I made a test script to satisfy my own curiosity: <lsl> key model; integer tog=0; vector lookat;

rotation Vec2RotBastard( vector V ) {

vector UP = < 0.0, 0.0, 1.0 >; vector LEFT = llVecNorm(UP%V); return llAxes2Rot(V, LEFT, UP); // demand for orthogonal, unit vectors is not fulfilled in general: // V is a unit vector in special cases only // UP and V are orthogonal in special cases only

}

rotation Vec2RotNorm( vector V ) {

V = llVecNorm( V ); vector UP = < 0.0, 0.0, 1.0 >; vector LEFT = llVecNorm(UP%V); return llAxes2Rot(V, LEFT, UP); // demand for orthogonal vectors is not fulfilled in general: // UP and V are orthogonal in special cases only

}

rotation Vec2RotTrue( vector V ) {

V = llVecNorm( V ); vector UP = < 0.0, 0.0, 1.0 >; vector LEFT = llVecNorm(UP%V); UP = llVecNorm(V%LEFT); // you want to keep the direction of V return llAxes2Rot(V, LEFT, UP);

}

rotation Vec2RotHor( vector V ) {

V = llVecNorm( V ); vector UP = < 0.0, 0.0, 1.0 >; vector LEFT = llVecNorm(UP%V); V = llVecNorm(LEFT%UP); // you want V confined to the horizontal plane return llAxes2Rot(V, LEFT, UP);

}

default {

touch_end(integer n) { llSetTimerEvent( 4.0 ); model = llDetectedKey(0); }

timer() { lookat = llList2Vector( llGetObjectDetails( model, [OBJECT_POS]), 0 ); if ( lookat != ZERO_VECTOR ) { if ( !tog ) { llSetColor ( <1.0, 0.2, 0.0>, ALL_SIDES ); llSetRot( Vec2RotBastard( lookat - llGetPos())); } else if ( tog == 1 ) { llSetColor ( <1.0, 1.0, 0.0>, ALL_SIDES ); llSetRot( Vec2RotNorm( lookat - llGetPos())); } else if ( tog == 2 ) { llSetColor ( <0.4, 1.0, 0.0>, ALL_SIDES ); llSetRot( Vec2RotTrue( lookat - llGetPos())); } else if ( tog == 3 ) { llSetColor ( <0.0, 0.6, 1.0>, ALL_SIDES ); llSetRot( Vec2RotHor( lookat - llGetPos())); } tog = ++tog % 4; } else { llSetColor ( <0.0, 0.0, 0.0>, ALL_SIDES ); llSetTimerEvent( 0.0 ); } }

}
</lsl>
How to use:
rezz a prim say x,y,z = 5.0, 0.2, 0.2 meters, put he script in and touch the prim.
It will point you for 4 sec with each routine in turn.
Move around and fly up to see where the prim will point.

Each routine will color the prim its own color:

- Red: "Bastard" routine, Not unit and not orthogonal.
- Yellow: "Norm" routine, unit vectors but not orthogonal.
- Green: "True" routine, true direction, the demands are met.
- Blue: "Hor" routine, direction in the horizontal plane only, the demands are met.