Game Development Reference
In-Depth Information
Furthermore, the waypoint arrow must be rendered with z-buffering disabled and
after all the other 3D objects in the world have been rendered. This ensures that
the arrow is always visible, even if there is a 3D object that should technically be
in front of it.
Listing 10.1
Waypoint Arrow
class
WaypointArrow
// Stores the current facing of the arrow
Vector3
facing
// 2D position of the arrow on screen
Vector2
screenPosition
// Current waypoint the arrow points at
Vector3
waypoint
// World transform matrix used to render the ar-
row
Matrix
worldTransform
// Computes world transform matrix from given
position/rotation
function
ComputeMatrix(
Vector3
worldPosition
,
Quaternion
rotation
)
// Scale, rotate, translate (but we don't
have a scale this time)
worldTransform
= CreateFromQuaternion(
rota-
tion
) *
CreateTranslation(
worldPosi-
tion
)
end
// Gets world position of the 3D arrow based on
screenPosition
function
ComputeWorldPosition()
// In order to do the unprojection, we need a
3D vector.
// The z component is the percent between the
