Sky color

[ataulien]

Ports some of the Sky-Logic from the old REGoth repository. This PR adds a component to the GameWorld, which calculates the sky color depending on the daytime using the Gothic 2 sky colors.

To test this, one can modify GameClock from this:

constexpr float CLOCK_SPEED_FACTOR  = SECONDS_IN_A_DAY/6000;

to

constexpr float CLOCK_SPEED_FACTOR  = SECONDS_IN_A_DAY/60;

for 60 second days.

[WIP]: Color is not applied to any meshes now, only the clear color is modified.
Using an indoor-world like OLDMINE.ZEN works for testing, but you need to peek through the wall with your camera to see the effect.

Also #35 should be merged first.

[mworchel]

Doesn't work for me. The sky stays blue in G1 and G2, no matter the world. It seems you forgot to commit the part where the Sky component is added to a scene object.

[ataulien]

Hmm, I remember amending that to the commit. I can't check what went wrong currently though. If you want, you can simply add the Sky component to the game world. Nothing else is required.

[mworchel]

When manually adding the component to the game world, the sky color does seem to change according to the time. Did you figure out what went wrong?

[mworchel]

Works.