Atmosphere changes for high-angle shots

[dbookstaber]

When shooting at high angles the bullet will travel through atmosphere with varying density. We can use standard models of how density changes with elevation to incorporate this variable into each step of the trajectory calculation.

[dbookstaber]

Actually this might already be implemented via the atmo.get_density_factor_and_mach_for_altitude() line in _trajectory().

[dbookstaber]

Yep, it is implemented that way. But we still need to validate this. (#9 is related/relevant.)

Possible tests:

• Lag-time at given time t should be smaller on high-angle shot than flat-fire trajectory.
• Velocity at the same time t should be higher for a high-angle shot than flat trajectory.

[dbookstaber]

We did confirm it while working on #11 (comment)

[gambon2010]

It could also be interesting to estimate wind speeds when shooting at high angles, in theory the higher the bullet goes, the higher the wind speed will be. For example by using the 'Wind profile power law', but I'm not sure how this could be implemented.