gluUnProject 3D- ( ). "" . gluUnProject , .
, "" , ( (1,0,0), (0,1,0), (0,0,1)). , . , ( ):

, "" , - . , . . .
,
, , , . , 800x800 , rubiks . , , , .
, gluUnProject ( , ):
p1 : (600, 600) -> (1, -0.5, 0)
p2 : (630, 605) -> (1.3, -0.505, 0)
: p2 - p1 = v = (0,3, -0,05, 0). , " ", , ( 0,3 x) ( rubiks ). "", x, y, z , :
v1 = (0.3, 0, 0)
v2 = (0, -0.05, 0)
v3 = (0, 0, 0)
, v1 = (0,3, 0, 0). . ( (0, 0, 1)). , (0, 1, 0) ( ) ( , , (0.02, 1.2, 0.8) β (0, 1, 0) , ). 0,3 ( , a).
, , ? , . :
p1 : (600, 600) -> (-1, 0.5, 0)
p2 : (630, 605) -> (-1.3, 0.505, 0)
. ? ! , p2 - p1 = v = (-0,3, 0,05, 0). (-0,3, 0, 0). , , .
- , ( ), x z ( ), .