Game Development Reference
In-Depth Information
float y = FastMath.sin(time ) * 5f;
position.set(x, y, z);
4. Then, we should set
localTranslation
of the sun. Since we want it to ap-
pear to be very far away, we add the camera's location. This way it will always
appear to be the same distance from the camera:
spatial.setLocalTranslation((cam.getLocation().add(position)));
5. We also want the sun to always face the camera. This is easily done by calling the
following code:
spatial.lookAt(cam.getLocation(), Vector3f.UNIT_Y);
6. If the
directionalLight
field is set, we should also set its direction. We get
the direction by inverting
position
, as shown in the following code:
directionalLight.setDirection(position.negate());
7. Finally, we increase the
time
value by a factor of
tpf
(depending on how fast
we want the sun to move). Since two PI in radians make up a circle, we start over
once
time
exceeds that value, using the following code:
time += tpf * timeFactor;
time = time % FastMath.TWO_PI;
8. Going back to the
application
class, we add the control to the
Geometry
sun and
Geometry
to the scene graph:
sun.addControl(sunControl);
rootNode.attachChild(sun);
The previous implementation can be enough for many games but it can be taken much
further. Let's explore how to make the sun color dynamic based on its height above the
horizon and how to also have a dynamic sky color by performing the following steps:
1. First of all, let's introduce two static
ColorRGBA
fields in the
SunControl
class called
dayColor
and
eveningColor
. We also add another
Color-
RGBA
field called
sunColor
.
2. In the
controlUpdate
method, we take the
y
value of the sun and divide it so
that we get a value between
-1
and
1
, and store this as the height.
