Editor.TetrahedronBuilder

//=============================================================================
// TetrahedronBuilder: Builds an octahedron (not tetrahedron) - experimental.
//=============================================================================
class TetrahedronBuilder
    extends BrushBuilder;

var() float Radius;
var() int SphereExtrapolation;
var() name GroupName;

function Extrapolate( int a, int b, int c, int Count, float Radius )
{
    local int ab,bc,ca;
    if( Count>1 )
    {
        ab=Vertexv( Radius*Normal(GetVertex(a)+GetVertex(b)) );
        bc=Vertexv( Radius*Normal(GetVertex(b)+GetVertex(c)) );
        ca=Vertexv( Radius*Normal(GetVertex(c)+GetVertex(a)) );
        Extrapolate(a,ab,ca,Count-1,Radius);
        Extrapolate(b,bc,ab,Count-1,Radius);
        Extrapolate(c,ca,bc,Count-1,Radius);
        Extrapolate(ab,bc,ca,Count-1,Radius);
        //wastes shared vertices
    }
    else Poly3i(+1,a,b,c);
}

function BuildTetrahedron( float R, int SphereExtrapolation )
{
    vertex3f( R,0,0);
    vertex3f(-R,0,0);
    vertex3f(0, R,0);
    vertex3f(0,-R,0);
    vertex3f(0,0, R);
    vertex3f(0,0,-R);

    Extrapolate(2,1,4,SphereExtrapolation,Radius);
    Extrapolate(1,3,4,SphereExtrapolation,Radius);
    Extrapolate(3,0,4,SphereExtrapolation,Radius);
    Extrapolate(0,2,4,SphereExtrapolation,Radius);
    Extrapolate(1,2,5,SphereExtrapolation,Radius);
    Extrapolate(3,1,5,SphereExtrapolation,Radius);
    Extrapolate(0,3,5,SphereExtrapolation,Radius);
    Extrapolate(2,0,5,SphereExtrapolation,Radius);
}

event bool Build()
{
    if( Radius<=0 || SphereExtrapolation<=0 )
        return BadParameters();

    BeginBrush( false, GroupName );
    BuildTetrahedron( Radius, SphereExtrapolation );
    return EndBrush();
}

defaultproperties
{
     Radius=256.000000
     SphereExtrapolation=1
     GroupName="Tetrahedron"
     BitmapFilename="BBSphere"
     ToolTip="Tetrahedron (Sphere)"
}