* Engine will now use it to render terrain
* Added directional light source
* Added dynamic shadows
* Moved visibility computation to CEngine
* Removed uniform buffers
Currently the engine can draw debug spheres to show crash sphere
positions. This extends this to draw arbitrary spheres and cuboids,
transformed arbitrarily. With these in place it's now very quick and
easy to create a debug visualisation - for example, it's a one-line code
change to render the bounding box or sphere of every EngineObject.
This commit improves rendering performance by doing a better job of
checking whether an object is visible via its bounding sphere or not.
The engine maintains a bounding box for each EngineBaseObject that's
exactly large enough to fit every vertex. From this, it computes a
bounding sphere, and only draws objects if the sphere is within the view
frustum. Previously, the bounding sphere was always centered on the
EngineBaseObject's origin, even for models where the bounding box center
is significantly offset from the origin. Now, the bounding sphere is
always the tightest sphere which fits the bounding box.
SystemTimeStamp used to be an opaque class, as it was provided by
`system_{linux/other/windows}.h`. Because of this, code dealt in
SystemTimeStamp pointers, and getting the current timestamp required a
memory allocation. Now SystemTimeStamp is just a
`std::chrono::time_point`, we can make the code cleaner and faster by
just directly keeping SystemTimeStamp instead of pointers around.
Also did some changes to make sure the "F1 to open SatCom" appears immediately (not after 0.1s),
and that mission timer won't start ticking in the first simulation frame (mainly for code battle initial pause)
Text rendering is now done in window coordinates corresponding to window
pixels to avoid floating-point rounding errors that show up as rendering
artifacts