begin
    ccX:= (PosX*m1) + (PosY*m5) + (PosZ*m9)  + m13;
    ccY:= (PosX*m2) + (PosY*m6) + (PosZ*m10) + m14;
    ccW:= (PosX*m4) + (PosY*m8) + (PosZ*m12) + m16;
 
    if (ccW › 0.1) then
    begin
 
        NDCx:= ccX / ccW;
        NDCy:= ccY / ccW;
 
        screenX:=  ((windowWidth  * 0.5) * NDCx) + (NDCx + (windowWidth  * 0.5));
        screenY:= -((windowHeight * 0.5) * NDCy) + (NDCy + (windowHeight * 0.5));
 
        sqrtif:=(sqr(PosXm-PosX))+(sqr(PosYm-PosY))+(sqr(PosZm-PosZ));
        if (sqrtif › 0) then vd:=sqrt(sqrtif) / 100;
 
        if (   (screenX ‹ windowWidth) and (screenY ‹ windowHeight) and (screenX › 0) and (screenY › 0) ) then
        begin
            _onEvent(onScreenX, screenX);
            _onEvent(onScreenY, screenY);
            _onEvent(onMeter,  vd);
            _onEvent(onVis);
        end;
    end;
 
end;